fix getsup (HH)

[luatex.git] / source / libs / luajit / LuaJIT-src / src / vm_x64.dasc

|// Low-level VM code for x64 CPUs in LJ_GC64 mode.
|// Bytecode interpreter, fast functions and helper functions.
|// Copyright (C) 2005-2016 Mike Pall. See Copyright Notice in luajit.h
|
|.arch x64
|.section code_op, code_sub
|
|.actionlist build_actionlist
|.globals GLOB_
|.globalnames globnames
|.externnames extnames
|
|//-----------------------------------------------------------------------
|
|.if WIN
|.define X64WIN, 1                      // Windows/x64 calling conventions.
|.endif
|
|// Fixed register assignments for the interpreter.
|// This is very fragile and has many dependencies. Caveat emptor.
|.define BASE,          rdx             // Not C callee-save, refetched anyway.
|.if X64WIN
|.define KBASE,         rdi             // Must be C callee-save.
|.define PC,            rsi             // Must be C callee-save.
|.define DISPATCH,      rbx             // Must be C callee-save.
|.define KBASEd,        edi
|.define PCd,           esi
|.define DISPATCHd,     ebx
|.else
|.define KBASE,         r15             // Must be C callee-save.
|.define PC,            rbx             // Must be C callee-save.
|.define DISPATCH,      r14             // Must be C callee-save.
|.define KBASEd,        r15d
|.define PCd,           ebx
|.define DISPATCHd,     r14d
|.endif
|
|.define RA,            rcx
|.define RAd,           ecx
|.define RAH,           ch
|.define RAL,           cl
|.define RB,            rbp             // Must be rbp (C callee-save).
|.define RBd,           ebp
|.define RC,            rax             // Must be rax.
|.define RCd,           eax
|.define RCW,           ax
|.define RCH,           ah
|.define RCL,           al
|.define OP,            RBd
|.define RD,            RC
|.define RDd,           RCd
|.define RDW,           RCW
|.define RDL,           RCL
|.define TMPR,          r10
|.define TMPRd,         r10d
|.define ITYPE,         r11
|.define ITYPEd,        r11d
|
|.if X64WIN
|.define CARG1,         rcx             // x64/WIN64 C call arguments.
|.define CARG2,         rdx
|.define CARG3,         r8
|.define CARG4,         r9
|.define CARG1d,        ecx
|.define CARG2d,        edx
|.define CARG3d,        r8d
|.define CARG4d,        r9d
|.else
|.define CARG1,         rdi             // x64/POSIX C call arguments.
|.define CARG2,         rsi
|.define CARG3,         rdx
|.define CARG4,         rcx
|.define CARG5,         r8
|.define CARG6,         r9
|.define CARG1d,        edi
|.define CARG2d,        esi
|.define CARG3d,        edx
|.define CARG4d,        ecx
|.define CARG5d,        r8d
|.define CARG6d,        r9d
|.endif
|
|// Type definitions. Some of these are only used for documentation.
|.type L,               lua_State
|.type GL,              global_State
|.type TVALUE,          TValue
|.type GCOBJ,           GCobj
|.type STR,             GCstr
|.type TAB,             GCtab
|.type LFUNC,           GCfuncL
|.type CFUNC,           GCfuncC
|.type PROTO,           GCproto
|.type UPVAL,           GCupval
|.type NODE,            Node
|.type NARGS,           int
|.type TRACE,           GCtrace
|.type SBUF,            SBuf
|
|// Stack layout while in interpreter. Must match with lj_frame.h.
|//-----------------------------------------------------------------------
|.if X64WIN             // x64/Windows stack layout
|
|.define CFRAME_SPACE,  aword*5                 // Delta for rsp (see <--).
|.macro saveregs_
|  push rdi; push rsi; push rbx
|  sub rsp, CFRAME_SPACE
|.endmacro
|.macro saveregs
|  push rbp; saveregs_
|.endmacro
|.macro restoreregs
|  add rsp, CFRAME_SPACE
|  pop rbx; pop rsi; pop rdi; pop rbp
|.endmacro
|
|.define SAVE_CFRAME,   aword [rsp+aword*13]
|.define SAVE_PC,       aword [rsp+aword*12]
|.define SAVE_L,        aword [rsp+aword*11]
|.define SAVE_ERRF,     dword [rsp+dword*21]
|.define SAVE_NRES,     dword [rsp+dword*20]
|//----- 16 byte aligned, ^^^ 32 byte register save area, owned by interpreter
|.define SAVE_RET,      aword [rsp+aword*9]     //<-- rsp entering interpreter.
|.define SAVE_R4,       aword [rsp+aword*8]
|.define SAVE_R3,       aword [rsp+aword*7]
|.define SAVE_R2,       aword [rsp+aword*6]
|.define SAVE_R1,       aword [rsp+aword*5]     //<-- rsp after register saves.
|.define ARG5,          aword [rsp+aword*4]
|.define CSAVE_4,       aword [rsp+aword*3]
|.define CSAVE_3,       aword [rsp+aword*2]
|.define CSAVE_2,       aword [rsp+aword*1]
|.define CSAVE_1,       aword [rsp]             //<-- rsp while in interpreter.
|//----- 16 byte aligned, ^^^ 32 byte register save area, owned by callee
|
|.define ARG5d,         dword [rsp+dword*8]
|.define TMP1,          ARG5                    // TMP1 overlaps ARG5
|.define TMP1d,         ARG5d
|.define TMP1hi,        dword [rsp+dword*9]
|.define MULTRES,       TMP1d                   // MULTRES overlaps TMP1d.
|
|//-----------------------------------------------------------------------
|.else                  // x64/POSIX stack layout
|
|.define CFRAME_SPACE,  aword*5                 // Delta for rsp (see <--).
|.macro saveregs_
|  push rbx; push r15; push r14
|.if NO_UNWIND
|  push r13; push r12
|.endif
|  sub rsp, CFRAME_SPACE
|.endmacro
|.macro saveregs
|  push rbp; saveregs_
|.endmacro
|.macro restoreregs
|  add rsp, CFRAME_SPACE
|.if NO_UNWIND
|  pop r12; pop r13
|.endif
|  pop r14; pop r15; pop rbx; pop rbp
|.endmacro
|
|//----- 16 byte aligned,
|.if NO_UNWIND
|.define SAVE_RET,      aword [rsp+aword*11]    //<-- rsp entering interpreter.
|.define SAVE_R4,       aword [rsp+aword*10]
|.define SAVE_R3,       aword [rsp+aword*9]
|.define SAVE_R2,       aword [rsp+aword*8]
|.define SAVE_R1,       aword [rsp+aword*7]
|.define SAVE_RU2,      aword [rsp+aword*6]
|.define SAVE_RU1,      aword [rsp+aword*5]     //<-- rsp after register saves.
|.else
|.define SAVE_RET,      aword [rsp+aword*9]     //<-- rsp entering interpreter.
|.define SAVE_R4,       aword [rsp+aword*8]
|.define SAVE_R3,       aword [rsp+aword*7]
|.define SAVE_R2,       aword [rsp+aword*6]
|.define SAVE_R1,       aword [rsp+aword*5]     //<-- rsp after register saves.
|.endif
|.define SAVE_CFRAME,   aword [rsp+aword*4]
|.define SAVE_PC,       aword [rsp+aword*3]
|.define SAVE_L,        aword [rsp+aword*2]
|.define SAVE_ERRF,     dword [rsp+dword*3]
|.define SAVE_NRES,     dword [rsp+dword*2]
|.define TMP1,          aword [rsp]             //<-- rsp while in interpreter.
|//----- 16 byte aligned
|
|.define TMP1d,         dword [rsp]
|.define TMP1hi,        dword [rsp+dword*1]
|.define MULTRES,       TMP1d                   // MULTRES overlaps TMP1d.
|
|.endif
|
|//-----------------------------------------------------------------------
|
|// Instruction headers.
|.macro ins_A; .endmacro
|.macro ins_AD; .endmacro
|.macro ins_AJ; .endmacro
|.macro ins_ABC; movzx RBd, RCH; movzx RCd, RCL; .endmacro
|.macro ins_AB_; movzx RBd, RCH; .endmacro
|.macro ins_A_C; movzx RCd, RCL; .endmacro
|.macro ins_AND; not RD; .endmacro
|
|// Instruction decode+dispatch. Carefully tuned (nope, lodsd is not faster).
|.macro ins_NEXT
|  mov RCd, [PC]
|  movzx RAd, RCH
|  movzx OP, RCL
|  add PC, 4
|  shr RCd, 16
|  jmp aword [DISPATCH+OP*8]
|.endmacro
|
|// Instruction footer.
|.if 1
|  // Replicated dispatch. Less unpredictable branches, but higher I-Cache use.
|  .define ins_next, ins_NEXT
|  .define ins_next_, ins_NEXT
|.else
|  // Common dispatch. Lower I-Cache use, only one (very) unpredictable branch.
|  // Affects only certain kinds of benchmarks (and only with -j off).
|  // Around 10%-30% slower on Core2, a lot more slower on P4.
|  .macro ins_next
|    jmp ->ins_next
|  .endmacro
|  .macro ins_next_
|  ->ins_next:
|    ins_NEXT
|  .endmacro
|.endif
|
|// Call decode and dispatch.
|.macro ins_callt
|  // BASE = new base, RB = LFUNC, RD = nargs+1, [BASE-8] = PC
|  mov PC, LFUNC:RB->pc
|  mov RAd, [PC]
|  movzx OP, RAL
|  movzx RAd, RAH
|  add PC, 4
|  jmp aword [DISPATCH+OP*8]
|.endmacro
|
|.macro ins_call
|  // BASE = new base, RB = LFUNC, RD = nargs+1
|  mov [BASE-8], PC
|  ins_callt
|.endmacro
|
|//-----------------------------------------------------------------------
|
|// Macros to clear or set tags.
|.macro cleartp, reg; shl reg, 17; shr reg, 17; .endmacro
|.macro settp, reg, tp
|  mov64 ITYPE, ((int64_t)tp<<47)
|  or reg, ITYPE
|.endmacro
|.macro settp, dst, reg, tp
|  mov64 dst, ((int64_t)tp<<47)
|  or dst, reg
|.endmacro
|.macro setint, reg
|  settp reg, LJ_TISNUM
|.endmacro
|.macro setint, dst, reg
|  settp dst, reg, LJ_TISNUM
|.endmacro
|
|// Macros to test operand types.
|.macro checktp_nc, reg, tp, target
|  mov ITYPE, reg
|  sar ITYPE, 47
|  cmp ITYPEd, tp
|  jne target
|.endmacro
|.macro checktp, reg, tp, target
|  mov ITYPE, reg
|  cleartp reg
|  sar ITYPE, 47
|  cmp ITYPEd, tp
|  jne target
|.endmacro
|.macro checktptp, src, tp, target
|  mov ITYPE, src
|  sar ITYPE, 47
|  cmp ITYPEd, tp
|  jne target
|.endmacro
|.macro checkstr, reg, target; checktp reg, LJ_TSTR, target; .endmacro
|.macro checktab, reg, target; checktp reg, LJ_TTAB, target; .endmacro
|.macro checkfunc, reg, target; checktp reg, LJ_TFUNC, target; .endmacro
|
|.macro checknumx, reg, target, jump
|  mov ITYPE, reg
|  sar ITYPE, 47
|  cmp ITYPEd, LJ_TISNUM
|  jump target
|.endmacro
|.macro checkint, reg, target; checknumx reg, target, jne; .endmacro
|.macro checkinttp, src, target; checknumx src, target, jne; .endmacro
|.macro checknum, reg, target; checknumx reg, target, jae; .endmacro
|.macro checknumtp, src, target; checknumx src, target, jae; .endmacro
|.macro checknumber, src, target; checknumx src, target, ja; .endmacro
|
|.macro mov_false, reg; mov64 reg, (int64_t)~((uint64_t)1<<47); .endmacro
|.macro mov_true, reg; mov64 reg, (int64_t)~((uint64_t)2<<47); .endmacro
|
|// These operands must be used with movzx.
|.define PC_OP, byte [PC-4]
|.define PC_RA, byte [PC-3]
|.define PC_RB, byte [PC-1]
|.define PC_RC, byte [PC-2]
|.define PC_RD, word [PC-2]
|
|.macro branchPC, reg
|  lea PC, [PC+reg*4-BCBIAS_J*4]
|.endmacro
|
|// Assumes DISPATCH is relative to GL.
#define DISPATCH_GL(field)      (GG_DISP2G + (int)offsetof(global_State, field))
#define DISPATCH_J(field)       (GG_DISP2J + (int)offsetof(jit_State, field))
|
#define PC2PROTO(field)  ((int)offsetof(GCproto, field)-(int)sizeof(GCproto))
|
|// Decrement hashed hotcount and trigger trace recorder if zero.
|.macro hotloop, reg
|  mov reg, PCd
|  shr reg, 1
|  and reg, HOTCOUNT_PCMASK
|  sub word [DISPATCH+reg+GG_DISP2HOT], HOTCOUNT_LOOP
|  jb ->vm_hotloop
|.endmacro
|
|.macro hotcall, reg
|  mov reg, PCd
|  shr reg, 1
|  and reg, HOTCOUNT_PCMASK
|  sub word [DISPATCH+reg+GG_DISP2HOT], HOTCOUNT_CALL
|  jb ->vm_hotcall
|.endmacro
|
|// Set current VM state.
|.macro set_vmstate, st
|  mov dword [DISPATCH+DISPATCH_GL(vmstate)], ~LJ_VMST_..st
|.endmacro
|
|.macro fpop1; fstp st1; .endmacro
|
|// Synthesize SSE FP constants.
|.macro sseconst_abs, reg, tmp          // Synthesize abs mask.
|  mov64 tmp, U64x(7fffffff,ffffffff); movd reg, tmp
|.endmacro
|
|.macro sseconst_hi, reg, tmp, val      // Synthesize hi-32 bit const.
|  mov64 tmp, U64x(val,00000000); movd reg, tmp
|.endmacro
|
|.macro sseconst_sign, reg, tmp         // Synthesize sign mask.
|  sseconst_hi reg, tmp, 80000000
|.endmacro
|.macro sseconst_1, reg, tmp            // Synthesize 1.0.
|  sseconst_hi reg, tmp, 3ff00000
|.endmacro
|.macro sseconst_m1, reg, tmp           // Synthesize -1.0.
|  sseconst_hi reg, tmp, bff00000
|.endmacro
|.macro sseconst_2p52, reg, tmp         // Synthesize 2^52.
|  sseconst_hi reg, tmp, 43300000
|.endmacro
|.macro sseconst_tobit, reg, tmp        // Synthesize 2^52 + 2^51.
|  sseconst_hi reg, tmp, 43380000
|.endmacro
|
|// Move table write barrier back. Overwrites reg.
|.macro barrierback, tab, reg
|  and byte tab->marked, (uint8_t)~LJ_GC_BLACK  // black2gray(tab)
|  mov reg, [DISPATCH+DISPATCH_GL(gc.grayagain)]
|  mov [DISPATCH+DISPATCH_GL(gc.grayagain)], tab
|  mov tab->gclist, reg
|.endmacro
|
|//-----------------------------------------------------------------------

/* Generate subroutines used by opcodes and other parts of the VM. */
/* The .code_sub section should be last to help static branch prediction. */
static void build_subroutines(BuildCtx *ctx)
{
  |.code_sub
  |
  |//-----------------------------------------------------------------------
  |//-- Return handling ----------------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |->vm_returnp:
  |  test PCd, FRAME_P
  |  jz ->cont_dispatch
  |
  |  // Return from pcall or xpcall fast func.
  |  and PC, -8
  |  sub BASE, PC                       // Restore caller base.
  |  lea RA, [RA+PC-8]                  // Rebase RA and prepend one result.
  |  mov PC, [BASE-8]                   // Fetch PC of previous frame.
  |  // Prepending may overwrite the pcall frame, so do it at the end.
  |  mov_true ITYPE
  |  mov aword [BASE+RA], ITYPE         // Prepend true to results.
  |
  |->vm_returnc:
  |  add RDd, 1                         // RD = nresults+1
  |  jz ->vm_unwind_yield
  |  mov MULTRES, RDd
  |  test PC, FRAME_TYPE
  |  jz ->BC_RET_Z                      // Handle regular return to Lua.
  |
  |->vm_return:
  |  // BASE = base, RA = resultofs, RD = nresults+1 (= MULTRES), PC = return
  |  xor PC, FRAME_C
  |  test PCd, FRAME_TYPE
  |  jnz ->vm_returnp
  |
  |  // Return to C.
  |  set_vmstate C
  |  and PC, -8
  |  sub PC, BASE
  |  neg PC                             // Previous base = BASE - delta.
  |
  |  sub RDd, 1
  |  jz >2
  |1:  // Move results down.
  |  mov RB, [BASE+RA]
  |  mov [BASE-16], RB
  |  add BASE, 8
  |  sub RDd, 1
  |  jnz <1
  |2:
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, PC
  |3:
  |  mov RDd, MULTRES
  |  mov RAd, SAVE_NRES                 // RA = wanted nresults+1
  |4:
  |  cmp RAd, RDd
  |  jne >6                             // More/less results wanted?
  |5:
  |  sub BASE, 16
  |  mov L:RB->top, BASE
  |
  |->vm_leave_cp:
  |  mov RA, SAVE_CFRAME                // Restore previous C frame.
  |  mov L:RB->cframe, RA
  |  xor eax, eax                       // Ok return status for vm_pcall.
  |
  |->vm_leave_unw:
  |  restoreregs
  |  ret
  |
  |6:
  |  jb >7                              // Less results wanted?
  |  // More results wanted. Check stack size and fill up results with nil.
  |  cmp BASE, L:RB->maxstack
  |  ja >8
  |  mov aword [BASE-16], LJ_TNIL
  |  add BASE, 8
  |  add RDd, 1
  |  jmp <4
  |
  |7:  // Less results wanted.
  |  test RAd, RAd
  |  jz <5                              // But check for LUA_MULTRET+1.
  |  sub RA, RD                         // Negative result!
  |  lea BASE, [BASE+RA*8]              // Correct top.
  |  jmp <5
  |
  |8:  // Corner case: need to grow stack for filling up results.
  |  // This can happen if:
  |  // - A C function grows the stack (a lot).
  |  // - The GC shrinks the stack in between.
  |  // - A return back from a lua_call() with (high) nresults adjustment.
  |  mov L:RB->top, BASE                // Save current top held in BASE (yes).
  |  mov MULTRES, RDd                   // Need to fill only remainder with nil.
  |  mov CARG2d, RAd
  |  mov CARG1, L:RB
  |  call extern lj_state_growstack     // (lua_State *L, int n)
  |  mov BASE, L:RB->top                // Need the (realloced) L->top in BASE.
  |  jmp <3
  |
  |->vm_unwind_yield:
  |  mov al, LUA_YIELD
  |  jmp ->vm_unwind_c_eh
  |
  |->vm_unwind_c:                       // Unwind C stack, return from vm_pcall.
  |  // (void *cframe, int errcode)
  |  mov eax, CARG2d                    // Error return status for vm_pcall.
  |  mov rsp, CARG1
  |->vm_unwind_c_eh:                    // Landing pad for external unwinder.
  |  mov L:RB, SAVE_L
  |  mov GL:RB, L:RB->glref
  |  mov dword GL:RB->vmstate, ~LJ_VMST_C
  |  jmp ->vm_leave_unw
  |
  |->vm_unwind_rethrow:
  |.if not X64WIN
  |  mov CARG1, SAVE_L
  |  mov CARG2d, eax
  |  restoreregs
  |  jmp extern lj_err_throw            // (lua_State *L, int errcode)
  |.endif
  |
  |->vm_unwind_ff:                      // Unwind C stack, return from ff pcall.
  |  // (void *cframe)
  |  and CARG1, CFRAME_RAWMASK
  |  mov rsp, CARG1
  |->vm_unwind_ff_eh:                   // Landing pad for external unwinder.
  |  mov L:RB, SAVE_L
  |  mov RDd, 1+1                       // Really 1+2 results, incr. later.
  |  mov BASE, L:RB->base
  |  mov DISPATCH, L:RB->glref          // Setup pointer to dispatch table.
  |  add DISPATCH, GG_G2DISP
  |  mov PC, [BASE-8]                   // Fetch PC of previous frame.
  |  mov_false RA
  |  mov RB, [BASE]
  |  mov [BASE-16], RA                  // Prepend false to error message.
  |  mov [BASE-8], RB
  |  mov RA, -16                        // Results start at BASE+RA = BASE-16.
  |  set_vmstate INTERP
  |  jmp ->vm_returnc                   // Increments RD/MULTRES and returns.
  |
  |//-----------------------------------------------------------------------
  |//-- Grow stack for calls -----------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |->vm_growstack_c:                    // Grow stack for C function.
  |  mov CARG2d, LUA_MINSTACK
  |  jmp >2
  |
  |->vm_growstack_v:                    // Grow stack for vararg Lua function.
  |  sub RD, 16                         // LJ_FR2
  |  jmp >1
  |
  |->vm_growstack_f:                    // Grow stack for fixarg Lua function.
  |  // BASE = new base, RD = nargs+1, RB = L, PC = first PC
  |  lea RD, [BASE+NARGS:RD*8-8]
  |1:
  |  movzx RAd, byte [PC-4+PC2PROTO(framesize)]
  |  add PC, 4                          // Must point after first instruction.
  |  mov L:RB->base, BASE
  |  mov L:RB->top, RD
  |  mov SAVE_PC, PC
  |  mov CARG2, RA
  |2:
  |  // RB = L, L->base = new base, L->top = top
  |  mov CARG1, L:RB
  |  call extern lj_state_growstack     // (lua_State *L, int n)
  |  mov BASE, L:RB->base
  |  mov RD, L:RB->top
  |  mov LFUNC:RB, [BASE-16]
  |  cleartp LFUNC:RB
  |  sub RD, BASE
  |  shr RDd, 3
  |  add NARGS:RDd, 1
  |  // BASE = new base, RB = LFUNC, RD = nargs+1
  |  ins_callt                          // Just retry the call.
  |
  |//-----------------------------------------------------------------------
  |//-- Entry points into the assembler VM ---------------------------------
  |//-----------------------------------------------------------------------
  |
  |->vm_resume:                         // Setup C frame and resume thread.
  |  // (lua_State *L, TValue *base, int nres1 = 0, ptrdiff_t ef = 0)
  |  saveregs
  |  mov L:RB, CARG1                    // Caveat: CARG1 may be RA.
  |  mov SAVE_L, CARG1
  |  mov RA, CARG2
  |  mov PCd, FRAME_CP
  |  xor RDd, RDd
  |  lea KBASE, [esp+CFRAME_RESUME]
  |  mov DISPATCH, L:RB->glref          // Setup pointer to dispatch table.
  |  add DISPATCH, GG_G2DISP
  |  mov SAVE_PC, RD                    // Any value outside of bytecode is ok.
  |  mov SAVE_CFRAME, RD
  |  mov SAVE_NRES, RDd
  |  mov SAVE_ERRF, RDd
  |  mov L:RB->cframe, KBASE
  |  cmp byte L:RB->status, RDL
  |  je >2                              // Initial resume (like a call).
  |
  |  // Resume after yield (like a return).
  |  mov [DISPATCH+DISPATCH_GL(cur_L)], L:RB
  |  set_vmstate INTERP
  |  mov byte L:RB->status, RDL
  |  mov BASE, L:RB->base
  |  mov RD, L:RB->top
  |  sub RD, RA
  |  shr RDd, 3
  |  add RDd, 1                         // RD = nresults+1
  |  sub RA, BASE                       // RA = resultofs
  |  mov PC, [BASE-8]
  |  mov MULTRES, RDd
  |  test PCd, FRAME_TYPE
  |  jz ->BC_RET_Z
  |  jmp ->vm_return
  |
  |->vm_pcall:                          // Setup protected C frame and enter VM.
  |  // (lua_State *L, TValue *base, int nres1, ptrdiff_t ef)
  |  saveregs
  |  mov PCd, FRAME_CP
  |  mov SAVE_ERRF, CARG4d
  |  jmp >1
  |
  |->vm_call:                           // Setup C frame and enter VM.
  |  // (lua_State *L, TValue *base, int nres1)
  |  saveregs
  |  mov PCd, FRAME_C
  |
  |1:  // Entry point for vm_pcall above (PC = ftype).
  |  mov SAVE_NRES, CARG3d
  |  mov L:RB, CARG1                    // Caveat: CARG1 may be RA.
  |  mov SAVE_L, CARG1
  |  mov RA, CARG2
  |
  |  mov DISPATCH, L:RB->glref          // Setup pointer to dispatch table.
  |  mov KBASE, L:RB->cframe            // Add our C frame to cframe chain.
  |  mov SAVE_CFRAME, KBASE
  |  mov SAVE_PC, L:RB                  // Any value outside of bytecode is ok.
  |  add DISPATCH, GG_G2DISP
  |  mov L:RB->cframe, rsp
  |
  |2:  // Entry point for vm_resume/vm_cpcall (RA = base, RB = L, PC = ftype).
  |  mov [DISPATCH+DISPATCH_GL(cur_L)], L:RB
  |  set_vmstate INTERP
  |  mov BASE, L:RB->base               // BASE = old base (used in vmeta_call).
  |  add PC, RA
  |  sub PC, BASE                       // PC = frame delta + frame type
  |
  |  mov RD, L:RB->top
  |  sub RD, RA
  |  shr NARGS:RDd, 3
  |  add NARGS:RDd, 1                   // RD = nargs+1
  |
  |->vm_call_dispatch:
  |  mov LFUNC:RB, [RA-16]
  |  checkfunc LFUNC:RB, ->vmeta_call   // Ensure KBASE defined and != BASE.
  |
  |->vm_call_dispatch_f:
  |  mov BASE, RA
  |  ins_call
  |  // BASE = new base, RB = func, RD = nargs+1, PC = caller PC
  |
  |->vm_cpcall:                         // Setup protected C frame, call C.
  |  // (lua_State *L, lua_CFunction func, void *ud, lua_CPFunction cp)
  |  saveregs
  |  mov L:RB, CARG1                    // Caveat: CARG1 may be RA.
  |  mov SAVE_L, CARG1
  |  mov SAVE_PC, L:RB                  // Any value outside of bytecode is ok.
  |
  |  mov KBASE, L:RB->stack             // Compute -savestack(L, L->top).
  |  sub KBASE, L:RB->top
  |   mov DISPATCH, L:RB->glref         // Setup pointer to dispatch table.
  |  mov SAVE_ERRF, 0                   // No error function.
  |  mov SAVE_NRES, KBASEd              // Neg. delta means cframe w/o frame.
  |   add DISPATCH, GG_G2DISP
  |  // Handler may change cframe_nres(L->cframe) or cframe_errfunc(L->cframe).
  |
  |  mov KBASE, L:RB->cframe            // Add our C frame to cframe chain.
  |  mov SAVE_CFRAME, KBASE
  |  mov L:RB->cframe, rsp
  |  mov [DISPATCH+DISPATCH_GL(cur_L)], L:RB
  |
  |  call CARG4                 // (lua_State *L, lua_CFunction func, void *ud)
  |  // TValue * (new base) or NULL returned in eax (RC).
  |  test RC, RC
  |  jz ->vm_leave_cp                   // No base? Just remove C frame.
  |  mov RA, RC
  |  mov PCd, FRAME_CP
  |  jmp <2                             // Else continue with the call.
  |
  |//-----------------------------------------------------------------------
  |//-- Metamethod handling ------------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |//-- Continuation dispatch ----------------------------------------------
  |
  |->cont_dispatch:
  |  // BASE = meta base, RA = resultofs, RD = nresults+1 (also in MULTRES)
  |  add RA, BASE
  |  and PC, -8
  |  mov RB, BASE
  |  sub BASE, PC                       // Restore caller BASE.
  |  mov aword [RA+RD*8-8], LJ_TNIL     // Ensure one valid arg.
  |  mov RC, RA                         // ... in [RC]
  |  mov PC, [RB-24]                    // Restore PC from [cont|PC].
  |  mov RA, qword [RB-32]              // May be negative on WIN64 with debug.
  |.if FFI
  |  cmp RA, 1
  |  jbe >1
  |.endif
  |  mov LFUNC:KBASE, [BASE-16]
  |  cleartp LFUNC:KBASE
  |  mov KBASE, LFUNC:KBASE->pc
  |  mov KBASE, [KBASE+PC2PROTO(k)]
  |  // BASE = base, RC = result, RB = meta base
  |  jmp RA                             // Jump to continuation.
  |
  |.if FFI
  |1:
  |  je ->cont_ffi_callback             // cont = 1: return from FFI callback.
  |  // cont = 0: Tail call from C function.
  |  sub RB, BASE
  |  shr RBd, 3
  |  lea RDd, [RBd-3]
  |  jmp ->vm_call_tail
  |.endif
  |
  |->cont_cat:                          // BASE = base, RC = result, RB = mbase
  |  movzx RAd, PC_RB
  |  sub RB, 32
  |  lea RA, [BASE+RA*8]
  |  sub RA, RB
  |  je ->cont_ra
  |  neg RA
  |  shr RAd, 3
  |.if X64WIN
  |  mov CARG3d, RAd
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE
  |  mov RC, [RC]
  |  mov [RB], RC
  |  mov CARG2, RB
  |.else
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE
  |  mov CARG3d, RAd
  |  mov RA, [RC]
  |  mov [RB], RA
  |  mov CARG2, RB
  |.endif
  |  jmp ->BC_CAT_Z
  |
  |//-- Table indexing metamethods -----------------------------------------
  |
  |->vmeta_tgets:
  |  settp STR:RC, LJ_TSTR              // STR:RC = GCstr *
  |  mov TMP1, STR:RC
  |  lea RC, TMP1
  |  cmp PC_OP, BC_GGET
  |  jne >1
  |  settp TAB:RA, TAB:RB, LJ_TTAB      // TAB:RB = GCtab *
  |  lea RB, [DISPATCH+DISPATCH_GL(tmptv)]  // Store fn->l.env in g->tmptv.
  |  mov [RB], TAB:RA
  |  jmp >2
  |
  |->vmeta_tgetb:
  |  movzx RCd, PC_RC
  |.if DUALNUM
  |  setint RC
  |  mov TMP1, RC
  |.else
  |  cvtsi2sd xmm0, RCd
  |  movsd TMP1, xmm0
  |.endif
  |  lea RC, TMP1
  |  jmp >1
  |
  |->vmeta_tgetv:
  |  movzx RCd, PC_RC                   // Reload TValue *k from RC.
  |  lea RC, [BASE+RC*8]
  |1:
  |  movzx RBd, PC_RB                   // Reload TValue *t from RB.
  |  lea RB, [BASE+RB*8]
  |2:
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE            // Caveat: CARG2/CARG3 may be BASE.
  |  mov CARG2, RB
  |  mov CARG3, RC
  |  mov L:RB, L:CARG1
  |  mov SAVE_PC, PC
  |  call extern lj_meta_tget           // (lua_State *L, TValue *o, TValue *k)
  |  // TValue * (finished) or NULL (metamethod) returned in eax (RC).
  |  mov BASE, L:RB->base
  |  test RC, RC
  |  jz >3
  |->cont_ra:                           // BASE = base, RC = result
  |  movzx RAd, PC_RA
  |  mov RB, [RC]
  |  mov [BASE+RA*8], RB
  |  ins_next
  |
  |3:  // Call __index metamethod.
  |  // BASE = base, L->top = new base, stack = cont/func/t/k
  |  mov RA, L:RB->top
  |  mov [RA-24], PC                    // [cont|PC]
  |  lea PC, [RA+FRAME_CONT]
  |  sub PC, BASE
  |  mov LFUNC:RB, [RA-16]              // Guaranteed to be a function here.
  |  mov NARGS:RDd, 2+1                 // 2 args for func(t, k).
  |  cleartp LFUNC:RB
  |  jmp ->vm_call_dispatch_f
  |
  |->vmeta_tgetr:
  |  mov CARG1, TAB:RB
  |  mov RB, BASE                       // Save BASE.
  |  mov CARG2d, RCd                    // Caveat: CARG2 == BASE
  |  call extern lj_tab_getinth         // (GCtab *t, int32_t key)
  |  // cTValue * or NULL returned in eax (RC).
  |  movzx RAd, PC_RA
  |  mov BASE, RB                       // Restore BASE.
  |  test RC, RC
  |  jnz ->BC_TGETR_Z
  |  mov ITYPE, LJ_TNIL
  |  jmp ->BC_TGETR2_Z
  |
  |//-----------------------------------------------------------------------
  |
  |->vmeta_tsets:
  |  settp STR:RC, LJ_TSTR              // STR:RC = GCstr *
  |  mov TMP1, STR:RC
  |  lea RC, TMP1
  |  cmp PC_OP, BC_GSET
  |  jne >1
  |  settp TAB:RA, TAB:RB, LJ_TTAB      // TAB:RB = GCtab *
  |  lea RB, [DISPATCH+DISPATCH_GL(tmptv)]  // Store fn->l.env in g->tmptv.
  |  mov [RB], TAB:RA
  |  jmp >2
  |
  |->vmeta_tsetb:
  |  movzx RCd, PC_RC
  |.if DUALNUM
  |  setint RC
  |  mov TMP1, RC
  |.else
  |  cvtsi2sd xmm0, RCd
  |  movsd TMP1, xmm0
  |.endif
  |  lea RC, TMP1
  |  jmp >1
  |
  |->vmeta_tsetv:
  |  movzx RCd, PC_RC                   // Reload TValue *k from RC.
  |  lea RC, [BASE+RC*8]
  |1:
  |  movzx RBd, PC_RB                   // Reload TValue *t from RB.
  |  lea RB, [BASE+RB*8]
  |2:
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE            // Caveat: CARG2/CARG3 may be BASE.
  |  mov CARG2, RB
  |  mov CARG3, RC
  |  mov L:RB, L:CARG1
  |  mov SAVE_PC, PC
  |  call extern lj_meta_tset           // (lua_State *L, TValue *o, TValue *k)
  |  // TValue * (finished) or NULL (metamethod) returned in eax (RC).
  |  mov BASE, L:RB->base
  |  test RC, RC
  |  jz >3
  |  // NOBARRIER: lj_meta_tset ensures the table is not black.
  |  movzx RAd, PC_RA
  |  mov RB, [BASE+RA*8]
  |  mov [RC], RB
  |->cont_nop:                          // BASE = base, (RC = result)
  |  ins_next
  |
  |3:  // Call __newindex metamethod.
  |  // BASE = base, L->top = new base, stack = cont/func/t/k/(v)
  |  mov RA, L:RB->top
  |  mov [RA-24], PC                    // [cont|PC]
  |  movzx RCd, PC_RA
  |  // Copy value to third argument.
  |  mov RB, [BASE+RC*8]
  |  mov [RA+16], RB
  |  lea PC, [RA+FRAME_CONT]
  |  sub PC, BASE
  |  mov LFUNC:RB, [RA-16]              // Guaranteed to be a function here.
  |  mov NARGS:RDd, 3+1                 // 3 args for func(t, k, v).
  |  cleartp LFUNC:RB
  |  jmp ->vm_call_dispatch_f
  |
  |->vmeta_tsetr:
  |.if X64WIN
  |  mov L:CARG1, SAVE_L
  |  mov CARG3d, RCd
  |  mov L:CARG1->base, BASE
  |  xchg CARG2, TAB:RB                 // Caveat: CARG2 == BASE.
  |.else
  |  mov L:CARG1, SAVE_L
  |  mov CARG2, TAB:RB
  |  mov L:CARG1->base, BASE
  |  mov RB, BASE                       // Save BASE.
  |  mov CARG3d, RCd                    // Caveat: CARG3 == BASE.
  |.endif
  |  mov SAVE_PC, PC
  |  call extern lj_tab_setinth  // (lua_State *L, GCtab *t, int32_t key)
  |  // TValue * returned in eax (RC).
  |  movzx RAd, PC_RA
  |  mov BASE, RB                       // Restore BASE.
  |  jmp ->BC_TSETR_Z
  |
  |//-- Comparison metamethods ---------------------------------------------
  |
  |->vmeta_comp:
  |  movzx RDd, PC_RD
  |  movzx RAd, PC_RA
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Caveat: CARG2/CARG3 == BASE.
  |.if X64WIN
  |  lea CARG3, [BASE+RD*8]
  |  lea CARG2, [BASE+RA*8]
  |.else
  |  lea CARG2, [BASE+RA*8]
  |  lea CARG3, [BASE+RD*8]
  |.endif
  |  mov CARG1, L:RB                    // Caveat: CARG1/CARG4 == RA.
  |  movzx CARG4d, PC_OP
  |  mov SAVE_PC, PC
  |  call extern lj_meta_comp   // (lua_State *L, TValue *o1, *o2, int op)
  |  // 0/1 or TValue * (metamethod) returned in eax (RC).
  |3:
  |  mov BASE, L:RB->base
  |  cmp RC, 1
  |  ja ->vmeta_binop
  |4:
  |  lea PC, [PC+4]
  |  jb >6
  |5:
  |  movzx RDd, PC_RD
  |  branchPC RD
  |6:
  |  ins_next
  |
  |->cont_condt:                        // BASE = base, RC = result
  |  add PC, 4
  |  mov ITYPE, [RC]
  |  sar ITYPE, 47
  |  cmp ITYPEd, LJ_TISTRUECOND         // Branch if result is true.
  |  jb <5
  |  jmp <6
  |
  |->cont_condf:                        // BASE = base, RC = result
  |  mov ITYPE, [RC]
  |  sar ITYPE, 47
  |  cmp ITYPEd, LJ_TISTRUECOND         // Branch if result is false.
  |  jmp <4
  |
  |->vmeta_equal:
  |  cleartp TAB:RD
  |  sub PC, 4
  |.if X64WIN
  |  mov CARG3, RD
  |  mov CARG4d, RBd
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Caveat: CARG2 == BASE.
  |  mov CARG2, RA
  |  mov CARG1, L:RB                    // Caveat: CARG1 == RA.
  |.else
  |  mov CARG2, RA
  |  mov CARG4d, RBd                    // Caveat: CARG4 == RA.
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Caveat: CARG3 == BASE.
  |  mov CARG3, RD
  |  mov CARG1, L:RB
  |.endif
  |  mov SAVE_PC, PC
  |  call extern lj_meta_equal  // (lua_State *L, GCobj *o1, *o2, int ne)
  |  // 0/1 or TValue * (metamethod) returned in eax (RC).
  |  jmp <3
  |
  |->vmeta_equal_cd:
  |.if FFI
  |  sub PC, 4
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG1, L:RB
  |  mov CARG2d, dword [PC-4]
  |  mov SAVE_PC, PC
  |  call extern lj_meta_equal_cd       // (lua_State *L, BCIns ins)
  |  // 0/1 or TValue * (metamethod) returned in eax (RC).
  |  jmp <3
  |.endif
  |
  |->vmeta_istype:
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Caveat: CARG2/CARG3 may be BASE.
  |  mov CARG2d, RAd
  |  mov CARG3d, RDd
  |  mov L:CARG1, L:RB
  |  mov SAVE_PC, PC
  |  call extern lj_meta_istype  // (lua_State *L, BCReg ra, BCReg tp)
  |  mov BASE, L:RB->base
  |  jmp <6
  |
  |//-- Arithmetic metamethods ---------------------------------------------
  |
  |->vmeta_arith_vno:
  |.if DUALNUM
  |  movzx RBd, PC_RB
  |  movzx RCd, PC_RC
  |.endif
  |->vmeta_arith_vn:
  |  lea RC, [KBASE+RC*8]
  |  jmp >1
  |
  |->vmeta_arith_nvo:
  |.if DUALNUM
  |  movzx RBd, PC_RB
  |  movzx RCd, PC_RC
  |.endif
  |->vmeta_arith_nv:
  |  lea TMPR, [KBASE+RC*8]
  |  lea RC, [BASE+RB*8]
  |  mov RB, TMPR
  |  jmp >2
  |
  |->vmeta_unm:
  |  lea RC, [BASE+RD*8]
  |  mov RB, RC
  |  jmp >2
  |
  |->vmeta_arith_vvo:
  |.if DUALNUM
  |  movzx RBd, PC_RB
  |  movzx RCd, PC_RC
  |.endif
  |->vmeta_arith_vv:
  |  lea RC, [BASE+RC*8]
  |1:
  |  lea RB, [BASE+RB*8]
  |2:
  |  lea RA, [BASE+RA*8]
  |.if X64WIN
  |  mov CARG3, RB
  |  mov CARG4, RC
  |  movzx RCd, PC_OP
  |  mov ARG5d, RCd
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Caveat: CARG2 == BASE.
  |  mov CARG2, RA
  |  mov CARG1, L:RB                    // Caveat: CARG1 == RA.
  |.else
  |  movzx CARG5d, PC_OP
  |  mov CARG2, RA
  |  mov CARG4, RC                      // Caveat: CARG4 == RA.
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE            // Caveat: CARG3 == BASE.
  |  mov CARG3, RB
  |  mov L:RB, L:CARG1
  |.endif
  |  mov SAVE_PC, PC
  |  call extern lj_meta_arith  // (lua_State *L, TValue *ra,*rb,*rc, BCReg op)
  |  // NULL (finished) or TValue * (metamethod) returned in eax (RC).
  |  mov BASE, L:RB->base
  |  test RC, RC
  |  jz ->cont_nop
  |
  |  // Call metamethod for binary op.
  |->vmeta_binop:
  |  // BASE = base, RC = new base, stack = cont/func/o1/o2
  |  mov RA, RC
  |  sub RC, BASE
  |  mov [RA-24], PC                    // [cont|PC]
  |  lea PC, [RC+FRAME_CONT]
  |  mov NARGS:RDd, 2+1                 // 2 args for func(o1, o2).
  |  jmp ->vm_call_dispatch
  |
  |->vmeta_len:
  |  movzx RDd, PC_RD
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  lea CARG2, [BASE+RD*8]             // Caveat: CARG2 == BASE
  |  mov L:CARG1, L:RB
  |  mov SAVE_PC, PC
  |  call extern lj_meta_len            // (lua_State *L, TValue *o)
  |  // NULL (retry) or TValue * (metamethod) returned in eax (RC).
  |  mov BASE, L:RB->base
#if LJ_52
  |  test RC, RC
  |  jne ->vmeta_binop                  // Binop call for compatibility.
  |  movzx RDd, PC_RD
  |  mov TAB:CARG1, [BASE+RD*8]
  |  cleartp TAB:CARG1
  |  jmp ->BC_LEN_Z
#else
  |  jmp ->vmeta_binop                  // Binop call for compatibility.
#endif
  |
  |//-- Call metamethod ----------------------------------------------------
  |
  |->vmeta_call_ra:
  |  lea RA, [BASE+RA*8+16]
  |->vmeta_call:                        // Resolve and call __call metamethod.
  |  // BASE = old base, RA = new base, RC = nargs+1, PC = return
  |  mov TMP1d, NARGS:RDd               // Save RA, RC for us.
  |  mov RB, RA
  |.if X64WIN
  |  mov L:TMPR, SAVE_L
  |  mov L:TMPR->base, BASE             // Caveat: CARG2 is BASE.
  |  lea CARG2, [RA-16]
  |  lea CARG3, [RA+NARGS:RD*8-8]
  |  mov CARG1, L:TMPR                  // Caveat: CARG1 is RA.
  |.else
  |  mov L:CARG1, SAVE_L
  |  mov L:CARG1->base, BASE            // Caveat: CARG3 is BASE.
  |  lea CARG2, [RA-16]
  |  lea CARG3, [RA+NARGS:RD*8-8]
  |.endif
  |  mov SAVE_PC, PC
  |  call extern lj_meta_call   // (lua_State *L, TValue *func, TValue *top)
  |  mov RA, RB
  |  mov L:RB, SAVE_L
  |  mov BASE, L:RB->base
  |  mov NARGS:RDd, TMP1d
  |  mov LFUNC:RB, [RA-16]
  |  cleartp LFUNC:RB
  |  add NARGS:RDd, 1
  |  // This is fragile. L->base must not move, KBASE must always be defined.
  |  cmp KBASE, BASE                    // Continue with CALLT if flag set.
  |  je ->BC_CALLT_Z
  |  mov BASE, RA
  |  ins_call                           // Otherwise call resolved metamethod.
  |
  |//-- Argument coercion for 'for' statement ------------------------------
  |
  |->vmeta_for:
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG2, RA                      // Caveat: CARG2 == BASE
  |  mov L:CARG1, L:RB                  // Caveat: CARG1 == RA
  |  mov SAVE_PC, PC
  |  call extern lj_meta_for    // (lua_State *L, TValue *base)
  |  mov BASE, L:RB->base
  |  mov RCd, [PC-4]
  |  movzx RAd, RCH
  |  movzx OP, RCL
  |  shr RCd, 16
  |  jmp aword [DISPATCH+OP*8+GG_DISP2STATIC]   // Retry FORI or JFORI.
  |
  |//-----------------------------------------------------------------------
  |//-- Fast functions -----------------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |.macro .ffunc, name
  |->ff_ .. name:
  |.endmacro
  |
  |.macro .ffunc_1, name
  |->ff_ .. name:
  |  cmp NARGS:RDd, 1+1;  jb ->fff_fallback
  |.endmacro
  |
  |.macro .ffunc_2, name
  |->ff_ .. name:
  |  cmp NARGS:RDd, 2+1;  jb ->fff_fallback
  |.endmacro
  |
  |.macro .ffunc_n, name, op
  |  .ffunc_1 name
  |  checknumtp [BASE], ->fff_fallback
  |  op xmm0, qword [BASE]
  |.endmacro
  |
  |.macro .ffunc_n, name
  |  .ffunc_n name, movsd
  |.endmacro
  |
  |.macro .ffunc_nn, name
  |  .ffunc_2 name
  |  checknumtp [BASE], ->fff_fallback
  |  checknumtp [BASE+8], ->fff_fallback
  |  movsd xmm0, qword [BASE]
  |  movsd xmm1, qword [BASE+8]
  |.endmacro
  |
  |// Inlined GC threshold check. Caveat: uses label 1.
  |.macro ffgccheck
  |  mov RB, [DISPATCH+DISPATCH_GL(gc.total)]
  |  cmp RB, [DISPATCH+DISPATCH_GL(gc.threshold)]
  |  jb >1
  |  call ->fff_gcstep
  |1:
  |.endmacro
  |
  |//-- Base library: checks -----------------------------------------------
  |
  |.ffunc_1 assert
  |  mov ITYPE, [BASE]
  |  mov RB, ITYPE
  |  sar ITYPE, 47
  |  cmp ITYPEd, LJ_TISTRUECOND; jae ->fff_fallback
  |  mov PC, [BASE-8]
  |  mov MULTRES, RDd
  |  mov RB, [BASE]
  |  mov [BASE-16], RB
  |  sub RDd, 2
  |  jz >2
  |  mov RA, BASE
  |1:
  |  add RA, 8
  |  mov RB, [RA]
  |  mov [RA-16], RB
  |  sub RDd, 1
  |  jnz <1
  |2:
  |  mov RDd, MULTRES
  |  jmp ->fff_res_
  |
  |.ffunc_1 type
  |  mov RC, [BASE]
  |  sar RC, 47
  |  mov RBd, LJ_TISNUM
  |  cmp RCd, RBd
  |  cmovb RCd, RBd
  |  not RCd
  |2:
  |  mov CFUNC:RB, [BASE-16]
  |  cleartp CFUNC:RB
  |  mov STR:RC, [CFUNC:RB+RC*8+((char *)(&((GCfuncC *)0)->upvalue))]
  |  mov PC, [BASE-8]
  |  settp STR:RC, LJ_TSTR
  |  mov [BASE-16], STR:RC
  |  jmp ->fff_res1
  |
  |//-- Base library: getters and setters ---------------------------------
  |
  |.ffunc_1 getmetatable
  |  mov TAB:RB, [BASE]
  |  mov PC, [BASE-8]
  |  checktab TAB:RB, >6
  |1:  // Field metatable must be at same offset for GCtab and GCudata!
  |  mov TAB:RB, TAB:RB->metatable
  |2:
  |  test TAB:RB, TAB:RB
  |  mov aword [BASE-16], LJ_TNIL
  |  jz ->fff_res1
  |  settp TAB:RC, TAB:RB, LJ_TTAB
  |  mov [BASE-16], TAB:RC              // Store metatable as default result.
  |  mov STR:RC, [DISPATCH+DISPATCH_GL(gcroot)+8*(GCROOT_MMNAME+MM_metatable)]
  |  mov RAd, TAB:RB->hmask
  |  and RAd, STR:RC->hash
  |  settp STR:RC, LJ_TSTR
  |  imul RAd, #NODE
  |  add NODE:RA, TAB:RB->node
  |3:  // Rearranged logic, because we expect _not_ to find the key.
  |  cmp NODE:RA->key, STR:RC
  |  je >5
  |4:
  |  mov NODE:RA, NODE:RA->next
  |  test NODE:RA, NODE:RA
  |  jnz <3
  |  jmp ->fff_res1                     // Not found, keep default result.
  |5:
  |  mov RB, NODE:RA->val
  |  cmp RB, LJ_TNIL; je ->fff_res1     // Ditto for nil value.
  |  mov [BASE-16], RB                  // Return value of mt.__metatable.
  |  jmp ->fff_res1
  |
  |6:
  |  cmp ITYPEd, LJ_TUDATA; je <1
  |  cmp ITYPEd, LJ_TISNUM; ja >7
  |  mov ITYPEd, LJ_TISNUM
  |7:
  |  not ITYPEd
  |  mov TAB:RB, [DISPATCH+ITYPE*8+DISPATCH_GL(gcroot[GCROOT_BASEMT])]
  |  jmp <2
  |
  |.ffunc_2 setmetatable
  |  mov TAB:RB, [BASE]
  |  mov TAB:TMPR, TAB:RB
  |  checktab TAB:RB, ->fff_fallback
  |  // Fast path: no mt for table yet and not clearing the mt.
  |  cmp aword TAB:RB->metatable, 0; jne ->fff_fallback
  |  mov TAB:RA, [BASE+8]
  |  checktab TAB:RA, ->fff_fallback
  |  mov TAB:RB->metatable, TAB:RA
  |  mov PC, [BASE-8]
  |  mov [BASE-16], TAB:TMPR                    // Return original table.
  |  test byte TAB:RB->marked, LJ_GC_BLACK      // isblack(table)
  |  jz >1
  |  // Possible write barrier. Table is black, but skip iswhite(mt) check.
  |  barrierback TAB:RB, RC
  |1:
  |  jmp ->fff_res1
  |
  |.ffunc_2 rawget
  |.if X64WIN
  |  mov TAB:RA, [BASE]
  |  checktab TAB:RA, ->fff_fallback
  |  mov RB, BASE                       // Save BASE.
  |  lea CARG3, [BASE+8]
  |  mov CARG2, TAB:RA                  // Caveat: CARG2 == BASE.
  |  mov CARG1, SAVE_L
  |.else
  |  mov TAB:CARG2, [BASE]
  |  checktab TAB:CARG2, ->fff_fallback
  |  mov RB, BASE                       // Save BASE.
  |  lea CARG3, [BASE+8]                // Caveat: CARG3 == BASE.
  |  mov CARG1, SAVE_L
  |.endif
  |  call extern lj_tab_get     // (lua_State *L, GCtab *t, cTValue *key)
  |  // cTValue * returned in eax (RD).
  |  mov BASE, RB                       // Restore BASE.
  |  // Copy table slot.
  |  mov RB, [RD]
  |  mov PC, [BASE-8]
  |  mov [BASE-16], RB
  |  jmp ->fff_res1
  |
  |//-- Base library: conversions ------------------------------------------
  |
  |.ffunc tonumber
  |  // Only handles the number case inline (without a base argument).
  |  cmp NARGS:RDd, 1+1;  jne ->fff_fallback    // Exactly one argument.
  |  mov RB, [BASE]
  |  checknumber RB, ->fff_fallback
  |  mov PC, [BASE-8]
  |  mov [BASE-16], RB
  |  jmp ->fff_res1
  |
  |.ffunc_1 tostring
  |  // Only handles the string or number case inline.
  |  mov PC, [BASE-8]
  |  mov STR:RB, [BASE]
  |  checktp_nc STR:RB, LJ_TSTR, >3
  |  // A __tostring method in the string base metatable is ignored.
  |2:
  |  mov [BASE-16], STR:RB
  |  jmp ->fff_res1
  |3:  // Handle numbers inline, unless a number base metatable is present.
  |  cmp ITYPEd, LJ_TISNUM;  ja ->fff_fallback_1
  |  cmp aword [DISPATCH+DISPATCH_GL(gcroot[GCROOT_BASEMT_NUM])], 0
  |  jne ->fff_fallback
  |  ffgccheck                          // Caveat: uses label 1.
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Add frame since C call can throw.
  |  mov SAVE_PC, PC                    // Redundant (but a defined value).
  |.if not X64WIN
  |  mov CARG2, BASE                    // Otherwise: CARG2 == BASE
  |.endif
  |  mov L:CARG1, L:RB
  |.if DUALNUM
  |  call extern lj_strfmt_number       // (lua_State *L, cTValue *o)
  |.else
  |  call extern lj_strfmt_num          // (lua_State *L, lua_Number *np)
  |.endif
  |  // GCstr returned in eax (RD).
  |  mov BASE, L:RB->base
  |  settp STR:RB, RD, LJ_TSTR
  |  jmp <2
  |
  |//-- Base library: iterators -------------------------------------------
  |
  |.ffunc_1 next
  |  je >2                              // Missing 2nd arg?
  |1:
  |.if X64WIN
  |  mov RA, [BASE]
  |  checktab RA, ->fff_fallback
  |.else
  |  mov CARG2, [BASE]
  |  checktab CARG2, ->fff_fallback
  |.endif
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE               // Add frame since C call can throw.
  |  mov L:RB->top, BASE                // Dummy frame length is ok.
  |  mov PC, [BASE-8]
  |.if X64WIN
  |  lea CARG3, [BASE+8]
  |  mov CARG2, RA                      // Caveat: CARG2 == BASE.
  |  mov CARG1, L:RB
  |.else
  |  lea CARG3, [BASE+8]                // Caveat: CARG3 == BASE.
  |  mov CARG1, L:RB
  |.endif
  |  mov SAVE_PC, PC                    // Needed for ITERN fallback.
  |  call extern lj_tab_next    // (lua_State *L, GCtab *t, TValue *key)
  |  // Flag returned in eax (RD).
  |  mov BASE, L:RB->base
  |  test RDd, RDd;  jz >3              // End of traversal?
  |  // Copy key and value to results.
  |  mov RB, [BASE+8]
  |  mov RD, [BASE+16]
  |  mov [BASE-16], RB
  |  mov [BASE-8], RD
  |->fff_res2:
  |  mov RDd, 1+2
  |  jmp ->fff_res
  |2:  // Set missing 2nd arg to nil.
  |  mov aword [BASE+8], LJ_TNIL
  |  jmp <1
  |3:  // End of traversal: return nil.
  |  mov aword [BASE-16], LJ_TNIL
  |  jmp ->fff_res1
  |
  |.ffunc_1 pairs
  |  mov TAB:RB, [BASE]
  |  mov TMPR, TAB:RB
  |  checktab TAB:RB, ->fff_fallback
#if LJ_52
  |  cmp aword TAB:RB->metatable, 0; jne ->fff_fallback
#endif
  |  mov CFUNC:RD, [BASE-16]
  |  cleartp CFUNC:RD
  |  mov CFUNC:RD, CFUNC:RD->upvalue[0]
  |  settp CFUNC:RD, LJ_TFUNC
  |  mov PC, [BASE-8]
  |  mov [BASE-16], CFUNC:RD
  |  mov [BASE-8], TMPR
  |  mov aword [BASE], LJ_TNIL
  |  mov RDd, 1+3
  |  jmp ->fff_res
  |
  |.ffunc_2 ipairs_aux
  |  mov TAB:RB, [BASE]
  |  checktab TAB:RB, ->fff_fallback
  |.if DUALNUM
  |  mov RA, [BASE+8]
  |  checkint RA, ->fff_fallback
  |.else
  |  checknumtp [BASE+8], ->fff_fallback
  |  movsd xmm0, qword [BASE+8]
  |.endif
  |  mov PC, [BASE-8]
  |.if DUALNUM
  |  add RAd, 1
  |  setint ITYPE, RA
  |  mov [BASE-16], ITYPE
  |.else
  |  sseconst_1 xmm1, TMPR
  |  addsd xmm0, xmm1
  |  cvttsd2si RAd, xmm0
  |  movsd qword [BASE-16], xmm0
  |.endif
  |  cmp RAd, TAB:RB->asize;  jae >2    // Not in array part?
  |  mov RD, TAB:RB->array
  |  lea RD, [RD+RA*8]
  |1:
  |  cmp aword [RD], LJ_TNIL;  je ->fff_res0
  |  // Copy array slot.
  |  mov RB, [RD]
  |  mov [BASE-8], RB
  |  jmp ->fff_res2
  |2:  // Check for empty hash part first. Otherwise call C function.
  |  cmp dword TAB:RB->hmask, 0; je ->fff_res0
  |.if X64WIN
  |  mov TMPR, BASE
  |  mov CARG2d, RAd
  |  mov CARG1, TAB:RB
  |  mov RB, TMPR
  |.else
  |  mov CARG1, TAB:RB
  |  mov RB, BASE                       // Save BASE.
  |  mov CARG2d, RAd                    // Caveat: CARG2 == BASE
  |.endif
  |  call extern lj_tab_getinth         // (GCtab *t, int32_t key)
  |  // cTValue * or NULL returned in eax (RD).
  |  mov BASE, RB
  |  test RD, RD
  |  jnz <1
  |->fff_res0:
  |  mov RDd, 1+0
  |  jmp ->fff_res
  |
  |.ffunc_1 ipairs
  |  mov TAB:RB, [BASE]
  |  mov TMPR, TAB:RB
  |  checktab TAB:RB, ->fff_fallback
#if LJ_52
  |  cmp aword TAB:RB->metatable, 0; jne ->fff_fallback
#endif
  |  mov CFUNC:RD, [BASE-16]
  |  cleartp CFUNC:RD
  |  mov CFUNC:RD, CFUNC:RD->upvalue[0]
  |  settp CFUNC:RD, LJ_TFUNC
  |  mov PC, [BASE-8]
  |  mov [BASE-16], CFUNC:RD
  |  mov [BASE-8], TMPR
  |.if DUALNUM
  |  mov64 RD, ((int64_t)LJ_TISNUM<<47)
  |  mov [BASE], RD
  |.else
  |  mov qword [BASE], 0
  |.endif
  |  mov RDd, 1+3
  |  jmp ->fff_res
  |
  |//-- Base library: catch errors ----------------------------------------
  |
  |.ffunc_1 pcall
  |  lea RA, [BASE+16]
  |  sub NARGS:RDd, 1
  |  mov PCd, 16+FRAME_PCALL
  |1:
  |  movzx RBd, byte [DISPATCH+DISPATCH_GL(hookmask)]
  |  shr RB, HOOK_ACTIVE_SHIFT
  |  and RB, 1
  |  add PC, RB                         // Remember active hook before pcall.
  |  // Note: this does a (harmless) copy of the function to the PC slot, too.
  |  mov KBASE, RD
  |2:
  |  mov RB, [RA+KBASE*8-24]
  |  mov [RA+KBASE*8-16], RB
  |  sub KBASE, 1
  |  ja <2
  |  jmp ->vm_call_dispatch
  |
  |.ffunc_2 xpcall
  |  mov LFUNC:RA, [BASE+8]
  |  checktp_nc LFUNC:RA, LJ_TFUNC, ->fff_fallback
  |  mov LFUNC:RB, [BASE]               // Swap function and traceback.
  |  mov [BASE], LFUNC:RA
  |  mov [BASE+8], LFUNC:RB
  |  lea RA, [BASE+24]
  |  sub NARGS:RDd, 2
  |  mov PCd, 24+FRAME_PCALL
  |  jmp <1
  |
  |//-- Coroutine library --------------------------------------------------
  |
  |.macro coroutine_resume_wrap, resume
  |.if resume
  |.ffunc_1 coroutine_resume
  |  mov L:RB, [BASE]
  |  cleartp L:RB
  |.else
  |.ffunc coroutine_wrap_aux
  |  mov CFUNC:RB, [BASE-16]
  |  cleartp CFUNC:RB
  |  mov L:RB, CFUNC:RB->upvalue[0].gcr
  |  cleartp L:RB
  |.endif
  |  mov PC, [BASE-8]
  |  mov SAVE_PC, PC
  |  mov TMP1, L:RB
  |.if resume
  |  checktptp [BASE], LJ_TTHREAD, ->fff_fallback
  |.endif
  |  cmp aword L:RB->cframe, 0; jne ->fff_fallback
  |  cmp byte L:RB->status, LUA_YIELD;  ja ->fff_fallback
  |  mov RA, L:RB->top
  |  je >1                              // Status != LUA_YIELD (i.e. 0)?
  |  cmp RA, L:RB->base                 // Check for presence of initial func.
  |  je ->fff_fallback
  |  mov PC, [RA-8]                     // Move initial function up.
  |  mov [RA], PC
  |  add RA, 8
  |1:
  |.if resume
  |  lea PC, [RA+NARGS:RD*8-16]         // Check stack space (-1-thread).
  |.else
  |  lea PC, [RA+NARGS:RD*8-8]          // Check stack space (-1).
  |.endif
  |  cmp PC, L:RB->maxstack; ja ->fff_fallback
  |  mov L:RB->top, PC
  |
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |.if resume
  |  add BASE, 8                        // Keep resumed thread in stack for GC.
  |.endif
  |  mov L:RB->top, BASE
  |.if resume
  |  lea RB, [BASE+NARGS:RD*8-24]       // RB = end of source for stack move.
  |.else
  |  lea RB, [BASE+NARGS:RD*8-16]       // RB = end of source for stack move.
  |.endif
  |  sub RB, PC                 // Relative to PC.
  |
  |  cmp PC, RA
  |  je >3
  |2:  // Move args to coroutine.
  |  mov RC, [PC+RB]
  |  mov [PC-8], RC
  |  sub PC, 8
  |  cmp PC, RA
  |  jne <2
  |3:
  |  mov CARG2, RA
  |  mov CARG1, TMP1
  |  call ->vm_resume                   // (lua_State *L, TValue *base, 0, 0)
  |
  |  mov L:RB, SAVE_L
  |  mov L:PC, TMP1
  |  mov BASE, L:RB->base
  |  mov [DISPATCH+DISPATCH_GL(cur_L)], L:RB
  |  set_vmstate INTERP
  |
  |  cmp eax, LUA_YIELD
  |  ja >8
  |4:
  |  mov RA, L:PC->base
  |  mov KBASE, L:PC->top
  |  mov L:PC->top, RA                  // Clear coroutine stack.
  |  mov PC, KBASE
  |  sub PC, RA
  |  je >6                              // No results?
  |  lea RD, [BASE+PC]
  |  shr PCd, 3
  |  cmp RD, L:RB->maxstack
  |  ja >9                              // Need to grow stack?
  |
  |  mov RB, BASE
  |  sub RB, RA
  |5:  // Move results from coroutine.
  |  mov RD, [RA]
  |  mov [RA+RB], RD
  |  add RA, 8
  |  cmp RA, KBASE
  |  jne <5
  |6:
  |.if resume
  |  lea RDd, [PCd+2]                   // nresults+1 = 1 + true + results.
  |  mov_true ITYPE                     // Prepend true to results.
  |  mov [BASE-8], ITYPE
  |.else
  |  lea RDd, [PCd+1]                   // nresults+1 = 1 + results.
  |.endif
  |7:
  |  mov PC, SAVE_PC
  |  mov MULTRES, RDd
  |.if resume
  |  mov RA, -8
  |.else
  |  xor RAd, RAd
  |.endif
  |  test PCd, FRAME_TYPE
  |  jz ->BC_RET_Z
  |  jmp ->vm_return
  |
  |8:  // Coroutine returned with error (at co->top-1).
  |.if resume
  |  mov_false ITYPE                    // Prepend false to results.
  |  mov [BASE-8], ITYPE
  |  mov RA, L:PC->top
  |  sub RA, 8
  |  mov L:PC->top, RA                  // Clear error from coroutine stack.
  |  // Copy error message.
  |  mov RD, [RA]
  |  mov [BASE], RD
  |  mov RDd, 1+2                       // nresults+1 = 1 + false + error.
  |  jmp <7
  |.else
  |  mov CARG2, L:PC
  |  mov CARG1, L:RB
  |  call extern lj_ffh_coroutine_wrap_err  // (lua_State *L, lua_State *co)
  |  // Error function does not return.
  |.endif
  |
  |9:  // Handle stack expansion on return from yield.
  |  mov L:RA, TMP1
  |  mov L:RA->top, KBASE               // Undo coroutine stack clearing.
  |  mov CARG2, PC
  |  mov CARG1, L:RB
  |  call extern lj_state_growstack     // (lua_State *L, int n)
  |  mov L:PC, TMP1
  |  mov BASE, L:RB->base
  |  jmp <4                             // Retry the stack move.
  |.endmacro
  |
  |  coroutine_resume_wrap 1            // coroutine.resume
  |  coroutine_resume_wrap 0            // coroutine.wrap
  |
  |.ffunc coroutine_yield
  |  mov L:RB, SAVE_L
  |  test aword L:RB->cframe, CFRAME_RESUME
  |  jz ->fff_fallback
  |  mov L:RB->base, BASE
  |  lea RD, [BASE+NARGS:RD*8-8]
  |  mov L:RB->top, RD
  |  xor RDd, RDd
  |  mov aword L:RB->cframe, RD
  |  mov al, LUA_YIELD
  |  mov byte L:RB->status, al
  |  jmp ->vm_leave_unw
  |
  |//-- Math library -------------------------------------------------------
  |
  |  .ffunc_1 math_abs
  |  mov RB, [BASE]
  |.if DUALNUM
  |  checkint RB, >3
  |  cmp RBd, 0; jns ->fff_resi
  |  neg RBd; js >2
  |->fff_resbit:
  |->fff_resi:
  |  setint RB
  |->fff_resRB:
  |  mov PC, [BASE-8]
  |  mov [BASE-16], RB
  |  jmp ->fff_res1
  |2:
  |  mov64 RB, U64x(41e00000,00000000)  // 2^31.
  |  jmp ->fff_resRB
  |3:
  |  ja ->fff_fallback
  |.else
  |  checknum RB, ->fff_fallback
  |.endif
  |  shl RB, 1
  |  shr RB, 1
  |  mov PC, [BASE-8]
  |  mov [BASE-16], RB
  |  jmp ->fff_res1
  |
  |.ffunc_n math_sqrt, sqrtsd
  |->fff_resxmm0:
  |  mov PC, [BASE-8]
  |  movsd qword [BASE-16], xmm0
  |  // fallthrough
  |
  |->fff_res1:
  |  mov RDd, 1+1
  |->fff_res:
  |  mov MULTRES, RDd
  |->fff_res_:
  |  test PCd, FRAME_TYPE
  |  jnz >7
  |5:
  |  cmp PC_RB, RDL                     // More results expected?
  |  ja >6
  |  // Adjust BASE. KBASE is assumed to be set for the calling frame.
  |  movzx RAd, PC_RA
  |  neg RA
  |  lea BASE, [BASE+RA*8-16]           // base = base - (RA+2)*8
  |  ins_next
  |
  |6:  // Fill up results with nil.
  |  mov aword [BASE+RD*8-24], LJ_TNIL
  |  add RD, 1
  |  jmp <5
  |
  |7:  // Non-standard return case.
  |  mov RA, -16                        // Results start at BASE+RA = BASE-16.
  |  jmp ->vm_return
  |
  |.macro math_round, func
  |  .ffunc math_ .. func
  |.if DUALNUM
  |  mov RB, [BASE]
  |  checknumx RB, ->fff_resRB, je
  |  ja ->fff_fallback
  |.else
  |  checknumtp [BASE], ->fff_fallback
  |.endif
  |  movsd xmm0, qword [BASE]
  |  call ->vm_ .. func .. _sse
  |.if DUALNUM
  |  cvttsd2si RBd, xmm0
  |  cmp RBd, 0x80000000
  |  jne ->fff_resi
  |  cvtsi2sd xmm1, RBd
  |  ucomisd xmm0, xmm1
  |  jp ->fff_resxmm0
  |  je ->fff_resi
  |.endif
  |  jmp ->fff_resxmm0
  |.endmacro
  |
  |  math_round floor
  |  math_round ceil
  |
  |.ffunc math_log
  |  cmp NARGS:RDd, 1+1; jne ->fff_fallback     // Exactly one argument.
  |  checknumtp [BASE], ->fff_fallback
  |  movsd xmm0, qword [BASE]
  |  mov RB, BASE
  |  call extern log
  |  mov BASE, RB
  |  jmp ->fff_resxmm0
  |
  |.macro math_extern, func
  |  .ffunc_n math_ .. func
  |  mov RB, BASE
  |  call extern func
  |  mov BASE, RB
  |  jmp ->fff_resxmm0
  |.endmacro
  |
  |.macro math_extern2, func
  |  .ffunc_nn math_ .. func
  |  mov RB, BASE
  |  call extern func
  |  mov BASE, RB
  |  jmp ->fff_resxmm0
  |.endmacro
  |
  |  math_extern log10
  |  math_extern exp
  |  math_extern sin
  |  math_extern cos
  |  math_extern tan
  |  math_extern asin
  |  math_extern acos
  |  math_extern atan
  |  math_extern sinh
  |  math_extern cosh
  |  math_extern tanh
  |  math_extern2 pow
  |  math_extern2 atan2
  |  math_extern2 fmod
  |
  |.ffunc_2 math_ldexp
  |  checknumtp [BASE], ->fff_fallback
  |  checknumtp [BASE+8], ->fff_fallback
  |  fld qword [BASE+8]
  |  fld qword [BASE]
  |  fscale
  |  fpop1
  |  mov PC, [BASE-8]
  |  fstp qword [BASE-16]
  |  jmp ->fff_res1
  |
  |.ffunc_n math_frexp
  |.if X64WIN
  |  lea CARG2, TMP1
  |.else
  |  lea CARG1, TMP1
  |.endif
  |  mov RB, BASE
  |  call extern frexp
  |  mov BASE, RB
  |  mov RBd, TMP1d
  |  mov PC, [BASE-8]
  |  movsd qword [BASE-16], xmm0
  |.if DUALNUM
  |  setint RB
  |  mov [BASE-8], RB
  |.else
  |  cvtsi2sd xmm1, RBd
  |  movsd qword [BASE-8], xmm1
  |.endif
  |  mov RDd, 1+2
  |  jmp ->fff_res
  |
  |.ffunc_n math_modf
  |.if X64WIN
  |  lea CARG2, [BASE-16]
  |.else
  |  lea CARG1, [BASE-16]
  |.endif
  |  mov PC, [BASE-8]
  |  mov RB, BASE
  |  call extern modf
  |  mov BASE, RB
  |  mov PC, [BASE-8]
  |  movsd qword [BASE-8], xmm0
  |  mov RDd, 1+2
  |  jmp ->fff_res
  |
  |.macro math_minmax, name, cmovop, sseop
  |  .ffunc name
  |  mov RAd, 2
  |.if DUALNUM
  |  mov RB, [BASE]
  |  checkint RB, >4
  |1:  // Handle integers.
  |  cmp RAd, RDd; jae ->fff_resRB
  |  mov TMPR, [BASE+RA*8-8]
  |  checkint TMPR, >3
  |  cmp RBd, TMPRd
  |  cmovop RB, TMPR
  |  add RAd, 1
  |  jmp <1
  |3:
  |  ja ->fff_fallback
  |  // Convert intermediate result to number and continue below.
  |  cvtsi2sd xmm0, RBd
  |  jmp >6
  |4:
  |  ja ->fff_fallback
  |.else
  |  checknumtp [BASE], ->fff_fallback
  |.endif
  |
  |  movsd xmm0, qword [BASE]
  |5:  // Handle numbers or integers.
  |  cmp RAd, RDd; jae ->fff_resxmm0
  |.if DUALNUM
  |  mov RB, [BASE+RA*8-8]
  |  checknumx RB, >6, jb
  |  ja ->fff_fallback
  |  cvtsi2sd xmm1, RBd
  |  jmp >7
  |.else
  |  checknumtp [BASE+RA*8-8], ->fff_fallback
  |.endif
  |6:
  |  movsd xmm1, qword [BASE+RA*8-8]
  |7:
  |  sseop xmm0, xmm1
  |  add RAd, 1
  |  jmp <5
  |.endmacro
  |
  |  math_minmax math_min, cmovg, minsd
  |  math_minmax math_max, cmovl, maxsd
  |
  |//-- String library -----------------------------------------------------
  |
  |.ffunc string_byte                   // Only handle the 1-arg case here.
  |  cmp NARGS:RDd, 1+1;  jne ->fff_fallback
  |  mov STR:RB, [BASE]
  |  checkstr STR:RB, ->fff_fallback
  |  mov PC, [BASE-8]
  |  cmp dword STR:RB->len, 1
  |  jb ->fff_res0                      // Return no results for empty string.
  |  movzx RBd, byte STR:RB[1]
  |.if DUALNUM
  |  jmp ->fff_resi
  |.else
  |  cvtsi2sd xmm0, RBd; jmp ->fff_resxmm0
  |.endif
  |
  |.ffunc string_char                   // Only handle the 1-arg case here.
  |  ffgccheck
  |  cmp NARGS:RDd, 1+1;  jne ->fff_fallback    // *Exactly* 1 arg.
  |.if DUALNUM
  |  mov RB, [BASE]
  |  checkint RB, ->fff_fallback
  |.else
  |  checknumtp [BASE], ->fff_fallback
  |  cvttsd2si RBd, qword [BASE]
  |.endif
  |  cmp RBd, 255;  ja ->fff_fallback
  |  mov TMP1d, RBd
  |  mov TMPRd, 1
  |  lea RD, TMP1                       // Points to stack. Little-endian.
  |->fff_newstr:
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG3d, TMPRd                  // Zero-extended to size_t.
  |  mov CARG2, RD
  |  mov CARG1, L:RB
  |  mov SAVE_PC, PC
  |  call extern lj_str_new             // (lua_State *L, char *str, size_t l)
  |->fff_resstr:
  |  // GCstr * returned in eax (RD).
  |  mov BASE, L:RB->base
  |  mov PC, [BASE-8]
  |  settp STR:RD, LJ_TSTR
  |  mov [BASE-16], STR:RD
  |  jmp ->fff_res1
  |
  |.ffunc string_sub
  |  ffgccheck
  |  mov TMPRd, -1
  |  cmp NARGS:RDd, 1+2;  jb ->fff_fallback
  |  jna >1
  |.if DUALNUM
  |  mov TMPR, [BASE+16]
  |  checkint TMPR, ->fff_fallback
  |.else
  |  checknumtp [BASE+16], ->fff_fallback
  |  cvttsd2si TMPRd, qword [BASE+16]
  |.endif
  |1:
  |  mov STR:RB, [BASE]
  |  checkstr STR:RB, ->fff_fallback
  |.if DUALNUM
  |  mov ITYPE, [BASE+8]
  |  mov RAd, ITYPEd                    // Must clear hiword for lea below.
  |  sar ITYPE, 47
  |  cmp ITYPEd, LJ_TISNUM
  |  jne ->fff_fallback
  |.else
  |  checknumtp [BASE+8], ->fff_fallback
  |  cvttsd2si RAd, qword [BASE+8]
  |.endif
  |  mov RCd, STR:RB->len
  |  cmp RCd, TMPRd                     // len < end? (unsigned compare)
  |  jb >5
  |2:
  |  test RAd, RAd                      // start <= 0?
  |  jle >7
  |3:
  |  sub TMPRd, RAd                     // start > end?
  |  jl ->fff_emptystr
  |  lea RD, [STR:RB+RAd+#STR-1]
  |  add TMPRd, 1
  |4:
  |  jmp ->fff_newstr
  |
  |5:  // Negative end or overflow.
  |  jl >6
  |  lea TMPRd, [TMPRd+RCd+1]           // end = end+(len+1)
  |  jmp <2
  |6:  // Overflow.
  |  mov TMPRd, RCd                     // end = len
  |  jmp <2
  |
  |7:  // Negative start or underflow.
  |  je >8
  |  add RAd, RCd                       // start = start+(len+1)
  |  add RAd, 1
  |  jg <3                              // start > 0?
  |8:  // Underflow.
  |  mov RAd, 1                         // start = 1
  |  jmp <3
  |
  |->fff_emptystr:  // Range underflow.
  |  xor TMPRd, TMPRd                   // Zero length. Any ptr in RD is ok.
  |  jmp <4
  |
  |.macro ffstring_op, name
  |  .ffunc_1 string_ .. name
  |  ffgccheck
  |.if X64WIN
  |  mov STR:TMPR, [BASE]
  |  checkstr STR:TMPR, ->fff_fallback
  |.else
  |  mov STR:CARG2, [BASE]
  |  checkstr STR:CARG2, ->fff_fallback
  |.endif
  |  mov L:RB, SAVE_L
  |   lea SBUF:CARG1, [DISPATCH+DISPATCH_GL(tmpbuf)]
  |  mov L:RB->base, BASE
  |.if X64WIN
  |  mov STR:CARG2, STR:TMPR            // Caveat: CARG2 == BASE
  |.endif
  |   mov RC, SBUF:CARG1->b
  |   mov SBUF:CARG1->L, L:RB
  |   mov SBUF:CARG1->p, RC
  |  mov SAVE_PC, PC
  |  call extern lj_buf_putstr_ .. name
  |  mov CARG1, rax
  |  call extern lj_buf_tostr
  |  jmp ->fff_resstr
  |.endmacro
  |
  |ffstring_op reverse
  |ffstring_op lower
  |ffstring_op upper
  |
  |//-- Bit library --------------------------------------------------------
  |
  |.macro .ffunc_bit, name, kind, fdef
  |  fdef name
  |.if kind == 2
  |  sseconst_tobit xmm1, RB
  |.endif
  |.if DUALNUM
  |  mov RB, [BASE]
  |  checkint RB, >1
  |.if kind > 0
  |  jmp >2
  |.else
  |  jmp ->fff_resbit
  |.endif
  |1:
  |  ja ->fff_fallback
  |  movd xmm0, RB
  |.else
  |  checknumtp [BASE], ->fff_fallback
  |  movsd xmm0, qword [BASE]
  |.endif
  |.if kind < 2
  |  sseconst_tobit xmm1, RB
  |.endif
  |  addsd xmm0, xmm1
  |  movd RBd, xmm0
  |2:
  |.endmacro
  |
  |.macro .ffunc_bit, name, kind
  |  .ffunc_bit name, kind, .ffunc_1
  |.endmacro
  |
  |.ffunc_bit bit_tobit, 0
  |  jmp ->fff_resbit
  |
  |.macro .ffunc_bit_op, name, ins
  |  .ffunc_bit name, 2
  |  mov TMPRd, NARGS:RDd               // Save for fallback.
  |  lea RD, [BASE+NARGS:RD*8-16]
  |1:
  |  cmp RD, BASE
  |  jbe ->fff_resbit
  |.if DUALNUM
  |  mov RA, [RD]
  |  checkint RA, >2
  |  ins RBd, RAd
  |  sub RD, 8
  |  jmp <1
  |2:
  |  ja ->fff_fallback_bit_op
  |  movd xmm0, RA
  |.else
  |  checknumtp [RD], ->fff_fallback_bit_op
  |  movsd xmm0, qword [RD]
  |.endif
  |  addsd xmm0, xmm1
  |  movd RAd, xmm0
  |  ins RBd, RAd
  |  sub RD, 8
  |  jmp <1
  |.endmacro
  |
  |.ffunc_bit_op bit_band, and
  |.ffunc_bit_op bit_bor, or
  |.ffunc_bit_op bit_bxor, xor
  |
  |.ffunc_bit bit_bswap, 1
  |  bswap RBd
  |  jmp ->fff_resbit
  |
  |.ffunc_bit bit_bnot, 1
  |  not RBd
  |.if DUALNUM
  |  jmp ->fff_resbit
  |.else
  |->fff_resbit:
  |  cvtsi2sd xmm0, RBd
  |  jmp ->fff_resxmm0
  |.endif
  |
  |->fff_fallback_bit_op:
  |  mov NARGS:RDd, TMPRd               // Restore for fallback
  |  jmp ->fff_fallback
  |
  |.macro .ffunc_bit_sh, name, ins
  |.if DUALNUM
  |  .ffunc_bit name, 1, .ffunc_2
  |  // Note: no inline conversion from number for 2nd argument!
  |  mov RA, [BASE+8]
  |  checkint RA, ->fff_fallback
  |.else
  |  .ffunc_nn name
  |  sseconst_tobit xmm2, RB
  |  addsd xmm0, xmm2
  |  addsd xmm1, xmm2
  |  movd RBd, xmm0
  |  movd RAd, xmm1
  |.endif
  |  ins RBd, cl                        // Assumes RA is ecx.
  |  jmp ->fff_resbit
  |.endmacro
  |
  |.ffunc_bit_sh bit_lshift, shl
  |.ffunc_bit_sh bit_rshift, shr
  |.ffunc_bit_sh bit_arshift, sar
  |.ffunc_bit_sh bit_rol, rol
  |.ffunc_bit_sh bit_ror, ror
  |
  |//-----------------------------------------------------------------------
  |
  |->fff_fallback_2:
  |  mov NARGS:RDd, 1+2                 // Other args are ignored, anyway.
  |  jmp ->fff_fallback
  |->fff_fallback_1:
  |  mov NARGS:RDd, 1+1                 // Other args are ignored, anyway.
  |->fff_fallback:                      // Call fast function fallback handler.
  |  // BASE = new base, RD = nargs+1
  |  mov L:RB, SAVE_L
  |  mov PC, [BASE-8]                   // Fallback may overwrite PC.
  |  mov SAVE_PC, PC                    // Redundant (but a defined value).
  |  mov L:RB->base, BASE
  |  lea RD, [BASE+NARGS:RD*8-8]
  |  lea RA, [RD+8*LUA_MINSTACK]        // Ensure enough space for handler.
  |  mov L:RB->top, RD
  |  mov CFUNC:RD, [BASE-16]
  |  cleartp CFUNC:RD
  |  cmp RA, L:RB->maxstack
  |  ja >5                              // Need to grow stack.
  |  mov CARG1, L:RB
  |  call aword CFUNC:RD->f             // (lua_State *L)
  |  mov BASE, L:RB->base
  |  // Either throws an error, or recovers and returns -1, 0 or nresults+1.
  |  test RDd, RDd; jg ->fff_res        // Returned nresults+1?
  |1:
  |  mov RA, L:RB->top
  |  sub RA, BASE
  |  shr RAd, 3
  |  test RDd, RDd
  |  lea NARGS:RDd, [RAd+1]
  |  mov LFUNC:RB, [BASE-16]
  |  jne ->vm_call_tail                 // Returned -1?
  |  cleartp LFUNC:RB
  |  ins_callt                          // Returned 0: retry fast path.
  |
  |// Reconstruct previous base for vmeta_call during tailcall.
  |->vm_call_tail:
  |  mov RA, BASE
  |  test PCd, FRAME_TYPE
  |  jnz >3
  |  movzx RBd, PC_RA
  |  neg RB
  |  lea BASE, [BASE+RB*8-16]           // base = base - (RB+2)*8
  |  jmp ->vm_call_dispatch             // Resolve again for tailcall.
  |3:
  |  mov RB, PC
  |  and RB, -8
  |  sub BASE, RB
  |  jmp ->vm_call_dispatch             // Resolve again for tailcall.
  |
  |5:  // Grow stack for fallback handler.
  |  mov CARG2d, LUA_MINSTACK
  |  mov CARG1, L:RB
  |  call extern lj_state_growstack     // (lua_State *L, int n)
  |  mov BASE, L:RB->base
  |  xor RDd, RDd                       // Simulate a return 0.
  |  jmp <1                             // Dumb retry (goes through ff first).
  |
  |->fff_gcstep:                        // Call GC step function.
  |  // BASE = new base, RD = nargs+1
  |  pop RB                             // Must keep stack at same level.
  |  mov TMP1, RB                       // Save return address
  |  mov L:RB, SAVE_L
  |  mov SAVE_PC, PC                    // Redundant (but a defined value).
  |  mov L:RB->base, BASE
  |  lea RD, [BASE+NARGS:RD*8-8]
  |  mov CARG1, L:RB
  |  mov L:RB->top, RD
  |  call extern lj_gc_step             // (lua_State *L)
  |  mov BASE, L:RB->base
  |  mov RD, L:RB->top
  |  sub RD, BASE
  |  shr RDd, 3
  |  add NARGS:RDd, 1
  |  mov RB, TMP1
  |  push RB                            // Restore return address.
  |  ret
  |
  |//-----------------------------------------------------------------------
  |//-- Special dispatch targets -------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |->vm_record:                         // Dispatch target for recording phase.
  |.if JIT
  |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
  |  test RDL, HOOK_VMEVENT             // No recording while in vmevent.
  |  jnz >5
  |  // Decrement the hookcount for consistency, but always do the call.
  |  test RDL, HOOK_ACTIVE
  |  jnz >1
  |  test RDL, LUA_MASKLINE|LUA_MASKCOUNT
  |  jz >1
  |  dec dword [DISPATCH+DISPATCH_GL(hookcount)]
  |  jmp >1
  |.endif
  |
  |->vm_rethook:                        // Dispatch target for return hooks.
  |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
  |  test RDL, HOOK_ACTIVE              // Hook already active?
  |  jnz >5
  |  jmp >1
  |
  |->vm_inshook:                        // Dispatch target for instr/line hooks.
  |  movzx RDd, byte [DISPATCH+DISPATCH_GL(hookmask)]
  |  test RDL, HOOK_ACTIVE              // Hook already active?
  |  jnz >5
  |
  |  test RDL, LUA_MASKLINE|LUA_MASKCOUNT
  |  jz >5
  |  dec dword [DISPATCH+DISPATCH_GL(hookcount)]
  |  jz >1
  |  test RDL, LUA_MASKLINE
  |  jz >5
  |1:
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG2, PC                      // Caveat: CARG2 == BASE
  |  mov CARG1, L:RB
  |  // SAVE_PC must hold the _previous_ PC. The callee updates it with PC.
  |  call extern lj_dispatch_ins        // (lua_State *L, const BCIns *pc)
  |3:
  |  mov BASE, L:RB->base
  |4:
  |  movzx RAd, PC_RA
  |5:
  |  movzx OP, PC_OP
  |  movzx RDd, PC_RD
  |  jmp aword [DISPATCH+OP*8+GG_DISP2STATIC]   // Re-dispatch to static ins.
  |
  |->cont_hook:                         // Continue from hook yield.
  |  add PC, 4
  |  mov RA, [RB-40]
  |  mov MULTRES, RAd                   // Restore MULTRES for *M ins.
  |  jmp <4
  |
  |->vm_hotloop:                        // Hot loop counter underflow.
  |.if JIT
  |  mov LFUNC:RB, [BASE-16]            // Same as curr_topL(L).
  |  cleartp LFUNC:RB
  |  mov RB, LFUNC:RB->pc
  |  movzx RDd, byte [RB+PC2PROTO(framesize)]
  |  lea RD, [BASE+RD*8]
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov L:RB->top, RD
  |  mov CARG2, PC
  |  lea CARG1, [DISPATCH+GG_DISP2J]
  |  mov aword [DISPATCH+DISPATCH_J(L)], L:RB
  |  mov SAVE_PC, PC
  |  call extern lj_trace_hot           // (jit_State *J, const BCIns *pc)
  |  jmp <3
  |.endif
  |
  |->vm_callhook:                       // Dispatch target for call hooks.
  |  mov SAVE_PC, PC
  |.if JIT
  |  jmp >1
  |.endif
  |
  |->vm_hotcall:                        // Hot call counter underflow.
  |.if JIT
  |  mov SAVE_PC, PC
  |  or PC, 1                           // Marker for hot call.
  |1:
  |.endif
  |  lea RD, [BASE+NARGS:RD*8-8]
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov L:RB->top, RD
  |  mov CARG2, PC
  |  mov CARG1, L:RB
  |  call extern lj_dispatch_call       // (lua_State *L, const BCIns *pc)
  |  // ASMFunction returned in eax/rax (RD).
  |  mov SAVE_PC, 0                     // Invalidate for subsequent line hook.
  |.if JIT
  |  and PC, -2
  |.endif
  |  mov BASE, L:RB->base
  |  mov RA, RD
  |  mov RD, L:RB->top
  |  sub RD, BASE
  |  mov RB, RA
  |  movzx RAd, PC_RA
  |  shr RDd, 3
  |  add NARGS:RDd, 1
  |  jmp RB
  |
  |->cont_stitch:                       // Trace stitching.
  |.if JIT
  |  // BASE = base, RC = result, RB = mbase
  |  mov ITYPEd, [RB-24]                // Save previous trace number.
  |  mov TMPRd, MULTRES
  |  movzx RAd, PC_RA
  |  lea RA, [BASE+RA*8]                // Call base.
  |  sub TMPRd, 1
  |  jz >2
  |1:  // Move results down.
  |  mov RB, [RC]
  |  mov [RA], RB
  |  add RC, 8
  |  add RA, 8
  |  sub TMPRd, 1
  |  jnz <1
  |2:
  |  movzx RCd, PC_RA
  |  movzx RBd, PC_RB
  |  add RC, RB
  |  lea RC, [BASE+RC*8-8]
  |3:
  |  cmp RC, RA
  |  ja >9                              // More results wanted?
  |
  |  mov RA, [DISPATCH+DISPATCH_J(trace)]
  |  mov TRACE:RD, [RA+ITYPE*8]
  |  test TRACE:RD, TRACE:RD
  |  jz ->cont_nop
  |  movzx RDd, word TRACE:RD->link
  |  cmp RDd, RBd
  |  je ->cont_nop                      // Blacklisted.
  |  test RDd, RDd
  |  jne =>BC_JLOOP                     // Jump to stitched trace.
  |
  |  // Stitch a new trace to the previous trace.
  |  mov [DISPATCH+DISPATCH_J(exitno)], RB
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG2, PC
  |  lea CARG1, [DISPATCH+GG_DISP2J]
  |  mov aword [DISPATCH+DISPATCH_J(L)], L:RB
  |  call extern lj_dispatch_stitch     // (jit_State *J, const BCIns *pc)
  |  mov BASE, L:RB->base
  |  jmp ->cont_nop
  |
  |9:  // Fill up results with nil.
  |  mov aword [RA], LJ_TNIL
  |  add RA, 8
  |  jmp <3
  |.endif
  |
  |->vm_profhook:                       // Dispatch target for profiler hook.
#if LJ_HASPROFILE
  |  mov L:RB, SAVE_L
  |  mov L:RB->base, BASE
  |  mov CARG2, PC                      // Caveat: CARG2 == BASE
  |  mov CARG1, L:RB
  |  call extern lj_dispatch_profile    // (lua_State *L, const BCIns *pc)
  |  mov BASE, L:RB->base
  |  // HOOK_PROFILE is off again, so re-dispatch to dynamic instruction.
  |  sub PC, 4
  |  jmp ->cont_nop
#endif
  |
  |//-----------------------------------------------------------------------
  |//-- Trace exit handler -------------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |// Called from an exit stub with the exit number on the stack.
  |// The 16 bit exit number is stored with two (sign-extended) push imm8.
  |->vm_exit_handler:
  |.if JIT
  |  push r13; push r12
  |  push r11; push r10; push r9; push r8
  |  push rdi; push rsi; push rbp; lea rbp, [rsp+88]; push rbp
  |  push rbx; push rdx; push rcx; push rax
  |  movzx RCd, byte [rbp-8]            // Reconstruct exit number.
  |  mov RCH, byte [rbp-16]
  |  mov [rbp-8], r15; mov [rbp-16], r14
  |  // Caveat: DISPATCH is rbx.
  |  mov DISPATCH, [ebp]
  |  mov RA, [DISPATCH+DISPATCH_GL(vmstate)]    // Get trace number.
  |  set_vmstate EXIT
  |  mov [DISPATCH+DISPATCH_J(exitno)], RC
  |  mov [DISPATCH+DISPATCH_J(parent)], RA
  |.if X64WIN
  |  sub rsp, 16*8+4*8                  // Room for SSE regs + save area.
  |.else
  |  sub rsp, 16*8                      // Room for SSE regs.
  |.endif
  |  add rbp, -128
  |  movsd qword [rbp-8],   xmm15; movsd qword [rbp-16],  xmm14
  |  movsd qword [rbp-24],  xmm13; movsd qword [rbp-32],  xmm12
  |  movsd qword [rbp-40],  xmm11; movsd qword [rbp-48],  xmm10
  |  movsd qword [rbp-56],  xmm9;  movsd qword [rbp-64],  xmm8
  |  movsd qword [rbp-72],  xmm7;  movsd qword [rbp-80],  xmm6
  |  movsd qword [rbp-88],  xmm5;  movsd qword [rbp-96],  xmm4
  |  movsd qword [rbp-104], xmm3;  movsd qword [rbp-112], xmm2
  |  movsd qword [rbp-120], xmm1;  movsd qword [rbp-128], xmm0
  |  // Caveat: RB is rbp.
  |  mov L:RB, [DISPATCH+DISPATCH_GL(cur_L)]
  |  mov BASE, [DISPATCH+DISPATCH_GL(jit_base)]
  |  mov aword [DISPATCH+DISPATCH_J(L)], L:RB
  |  mov L:RB->base, BASE
  |.if X64WIN
  |  lea CARG2, [rsp+4*8]
  |.else
  |  mov CARG2, rsp
  |.endif
  |  lea CARG1, [DISPATCH+GG_DISP2J]
  |  mov dword [DISPATCH+DISPATCH_GL(jit_base)], 0
  |  call extern lj_trace_exit          // (jit_State *J, ExitState *ex)
  |  // MULTRES or negated error code returned in eax (RD).
  |  mov RA, L:RB->cframe
  |  and RA, CFRAME_RAWMASK
  |  mov [RA+CFRAME_OFS_L], L:RB        // Set SAVE_L (on-trace resume/yield).
  |  mov BASE, L:RB->base
  |  mov PC, [RA+CFRAME_OFS_PC] // Get SAVE_PC.
  |  jmp >1
  |.endif
  |->vm_exit_interp:
  |  // RD = MULTRES or negated error code, BASE, PC and DISPATCH set.
  |.if JIT
  |  // Restore additional callee-save registers only used in compiled code.
  |.if X64WIN
  |  lea RA, [rsp+10*16+4*8]
  |1:
  |  movdqa xmm15, [RA-10*16]
  |  movdqa xmm14, [RA-9*16]
  |  movdqa xmm13, [RA-8*16]
  |  movdqa xmm12, [RA-7*16]
  |  movdqa xmm11, [RA-6*16]
  |  movdqa xmm10, [RA-5*16]
  |  movdqa xmm9, [RA-4*16]
  |  movdqa xmm8, [RA-3*16]
  |  movdqa xmm7, [RA-2*16]
  |  mov rsp, RA                        // Reposition stack to C frame.
  |  movdqa xmm6, [RA-1*16]
  |  mov r15, CSAVE_1
  |  mov r14, CSAVE_2
  |  mov r13, CSAVE_3
  |  mov r12, CSAVE_4
  |.else
  |  lea RA, [rsp+16]
  |1:
  |  mov r13, [RA-8]
  |  mov r12, [RA]
  |  mov rsp, RA                        // Reposition stack to C frame.
  |.endif
  |  test RDd, RDd; js >9               // Check for error from exit.
  |  mov L:RB, SAVE_L
  |  mov MULTRES, RDd
  |  mov LFUNC:KBASE, [BASE-16]
  |  cleartp LFUNC:KBASE
  |  mov KBASE, LFUNC:KBASE->pc
  |  mov KBASE, [KBASE+PC2PROTO(k)]
  |  mov L:RB->base, BASE
  |  mov dword [DISPATCH+DISPATCH_GL(jit_base)], 0
  |  set_vmstate INTERP
  |  // Modified copy of ins_next which handles function header dispatch, too.
  |  mov RCd, [PC]
  |  movzx RAd, RCH
  |  movzx OP, RCL
  |  add PC, 4
  |  shr RCd, 16
  |  cmp OP, BC_FUNCF                   // Function header?
  |  jb >3
  |  cmp OP, BC_FUNCC+2                 // Fast function?
  |  jae >4
  |2:
  |  mov RCd, MULTRES                   // RC/RD holds nres+1.
  |3:
  |  jmp aword [DISPATCH+OP*8]
  |
  |4:  // Check frame below fast function.
  |  mov RC, [BASE-8]
  |  test RCd, FRAME_TYPE
  |  jnz <2                             // Trace stitching continuation?
  |  // Otherwise set KBASE for Lua function below fast function.
  |  movzx RCd, byte [RC-3]
  |  neg RC
  |  mov LFUNC:KBASE, [BASE+RC*8-24]
  |  cleartp LFUNC:KBASE
  |  mov KBASE, LFUNC:KBASE->pc
  |  mov KBASE, [KBASE+PC2PROTO(k)]
  |  jmp <2
  |
  |9:  // Rethrow error from the right C frame.
  |  neg RD
  |  mov CARG1, L:RB
  |  mov CARG2, RD
  |  call extern lj_err_throw           // (lua_State *L, int errcode)
  |.endif
  |
  |//-----------------------------------------------------------------------
  |//-- Math helper functions ----------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |// FP value rounding. Called by math.floor/math.ceil fast functions
  |// and from JIT code. arg/ret is xmm0. xmm0-xmm3 and RD (eax) modified.
  |.macro vm_round, name, mode, cond
  |->name:
  |->name .. _sse:
  |  sseconst_abs xmm2, RD
  |  sseconst_2p52 xmm3, RD
  |  movaps xmm1, xmm0
  |  andpd xmm1, xmm2                   // |x|
  |  ucomisd xmm3, xmm1                 // No truncation if 2^52 <= |x|.
  |  jbe >1
  |  andnpd xmm2, xmm0                  // Isolate sign bit.
  |.if mode == 2                // trunc(x)?
  |  movaps xmm0, xmm1
  |  addsd xmm1, xmm3                   // (|x| + 2^52) - 2^52
  |  subsd xmm1, xmm3
  |  sseconst_1 xmm3, RD
  |  cmpsd xmm0, xmm1, 1                // |x| < result?
  |  andpd xmm0, xmm3
  |  subsd xmm1, xmm0                   // If yes, subtract -1.
  |  orpd xmm1, xmm2                    // Merge sign bit back in.
  |.else
  |  addsd xmm1, xmm3                   // (|x| + 2^52) - 2^52
  |  subsd xmm1, xmm3
  |  orpd xmm1, xmm2                    // Merge sign bit back in.
  |  .if mode == 1              // ceil(x)?
  |    sseconst_m1 xmm2, RD             // Must subtract -1 to preserve -0.
  |    cmpsd xmm0, xmm1, 6              // x > result?
  |  .else                      // floor(x)?
  |    sseconst_1 xmm2, RD
  |    cmpsd xmm0, xmm1, 1              // x < result?
  |  .endif
  |  andpd xmm0, xmm2
  |  subsd xmm1, xmm0                   // If yes, subtract +-1.
  |.endif
  |  movaps xmm0, xmm1
  |1:
  |  ret
  |.endmacro
  |
  |  vm_round vm_floor, 0, 1
  |  vm_round vm_ceil,  1, JIT
  |  vm_round vm_trunc, 2, JIT
  |
  |// FP modulo x%y. Called by BC_MOD* and vm_arith.
  |->vm_mod:
  |// Args in xmm0/xmm1, return value in xmm0.
  |// Caveat: xmm0-xmm5 and RC (eax) modified!
  |  movaps xmm5, xmm0
  |  divsd xmm0, xmm1
  |  sseconst_abs xmm2, RD
  |  sseconst_2p52 xmm3, RD
  |  movaps xmm4, xmm0
  |  andpd xmm4, xmm2                   // |x/y|
  |  ucomisd xmm3, xmm4                 // No truncation if 2^52 <= |x/y|.
  |  jbe >1
  |  andnpd xmm2, xmm0                  // Isolate sign bit.
  |  addsd xmm4, xmm3                   // (|x/y| + 2^52) - 2^52
  |  subsd xmm4, xmm3
  |  orpd xmm4, xmm2                    // Merge sign bit back in.
  |  sseconst_1 xmm2, RD
  |  cmpsd xmm0, xmm4, 1                // x/y < result?
  |  andpd xmm0, xmm2
  |  subsd xmm4, xmm0                   // If yes, subtract 1.0.
  |  movaps xmm0, xmm5
  |  mulsd xmm1, xmm4
  |  subsd xmm0, xmm1
  |  ret
  |1:
  |  mulsd xmm1, xmm0
  |  movaps xmm0, xmm5
  |  subsd xmm0, xmm1
  |  ret
  |
  |// Args in xmm0/eax. Ret in xmm0. xmm0-xmm1 and eax modified.
  |->vm_powi_sse:
  |  cmp eax, 1; jle >6                 // i<=1?
  |  // Now 1 < (unsigned)i <= 0x80000000.
  |1:  // Handle leading zeros.
  |  test eax, 1; jnz >2
  |  mulsd xmm0, xmm0
  |  shr eax, 1
  |  jmp <1
  |2:
  |  shr eax, 1; jz >5
  |  movaps xmm1, xmm0
  |3:  // Handle trailing bits.
  |  mulsd xmm0, xmm0
  |  shr eax, 1; jz >4
  |  jnc <3
  |  mulsd xmm1, xmm0
  |  jmp <3
  |4:
  |  mulsd xmm0, xmm1
  |5:
  |  ret
  |6:
  |  je <5                              // x^1 ==> x
  |  jb >7                              // x^0 ==> 1
  |  neg eax
  |  call <1
  |  sseconst_1 xmm1, RD
  |  divsd xmm1, xmm0
  |  movaps xmm0, xmm1
  |  ret
  |7:
  |  sseconst_1 xmm0, RD
  |  ret
  |
  |//-----------------------------------------------------------------------
  |//-- Miscellaneous functions --------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |// int lj_vm_cpuid(uint32_t f, uint32_t res[4])
  |->vm_cpuid:
  |  mov eax, CARG1d
  |  .if X64WIN; push rsi; mov rsi, CARG2; .endif
  |  push rbx
  |  cpuid
  |  mov [rsi], eax
  |  mov [rsi+4], ebx
  |  mov [rsi+8], ecx
  |  mov [rsi+12], edx
  |  pop rbx
  |  .if X64WIN; pop rsi; .endif
  |  ret
  |
  |//-----------------------------------------------------------------------
  |//-- Assertions ---------------------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |->assert_bad_for_arg_type:
#ifdef LUA_USE_ASSERT
  |  int3
#endif
  |  int3
  |
  |//-----------------------------------------------------------------------
  |//-- FFI helper functions -----------------------------------------------
  |//-----------------------------------------------------------------------
  |
  |// Handler for callback functions. Callback slot number in ah/al.
  |->vm_ffi_callback:
  |.if FFI
  |.type CTSTATE, CTState, PC
  |  saveregs_  // ebp/rbp already saved. ebp now holds global_State *.
  |  lea DISPATCH, [ebp+GG_G2DISP]
  |  mov CTSTATE, GL:ebp->ctype_state
  |  movzx eax, ax
  |  mov CTSTATE->cb.slot, eax
  |  mov CTSTATE->cb.gpr[0], CARG1
  |  mov CTSTATE->cb.gpr[1], CARG2
  |  mov CTSTATE->cb.gpr[2], CARG3
  |  mov CTSTATE->cb.gpr[3], CARG4
  |  movsd qword CTSTATE->cb.fpr[0], xmm0
  |  movsd qword CTSTATE->cb.fpr[1], xmm1
  |  movsd qword CTSTATE->cb.fpr[2], xmm2
  |  movsd qword CTSTATE->cb.fpr[3], xmm3
  |.if X64WIN
  |  lea rax, [rsp+CFRAME_SIZE+4*8]
  |.else
  |  lea rax, [rsp+CFRAME_SIZE]
  |  mov CTSTATE->cb.gpr[4], CARG5
  |  mov CTSTATE->cb.gpr[5], CARG6
  |  movsd qword CTSTATE->cb.fpr[4], xmm4
  |  movsd qword CTSTATE->cb.fpr[5], xmm5
  |  movsd qword CTSTATE->cb.fpr[6], xmm6
  |  movsd qword CTSTATE->cb.fpr[7], xmm7
  |.endif
  |  mov CTSTATE->cb.stack, rax
  |  mov CARG2, rsp
  |  mov SAVE_PC, CTSTATE               // Any value outside of bytecode is ok.
  |  mov CARG1, CTSTATE
  |  call extern lj_ccallback_enter     // (CTState *cts, void *cf)
  |  // lua_State * returned in eax (RD).
  |  set_vmstate INTERP
  |  mov BASE, L:RD->base
  |  mov RD, L:RD->top
  |  sub RD, BASE
  |  mov LFUNC:RB, [BASE-16]
  |  cleartp LFUNC:RB
  |  shr RD, 3
  |  add RD, 1
  |  ins_callt
  |.endif
  |
  |->cont_ffi_callback:                 // Return from FFI callback.
  |.if FFI
  |  mov L:RA, SAVE_L
  |  mov CTSTATE, [DISPATCH+DISPATCH_GL(ctype_state)]
  |  mov aword CTSTATE->L, L:RA
  |  mov L:RA->base, BASE
  |  mov L:RA->top, RB
  |  mov CARG1, CTSTATE
  |  mov CARG2, RC
  |  call extern lj_ccallback_leave     // (CTState *cts, TValue *o)
  |  mov rax, CTSTATE->cb.gpr[0]
  |  movsd xmm0, qword CTSTATE->cb.fpr[0]
  |  jmp ->vm_leave_unw
  |.endif
  |
  |->vm_ffi_call:                       // Call C function via FFI.
  |  // Caveat: needs special frame unwinding, see below.
  |.if FFI
  |  .type CCSTATE, CCallState, rbx
  |  push rbp; mov rbp, rsp; push rbx; mov CCSTATE, CARG1
  |
  |  // Readjust stack.
  |  mov eax, CCSTATE->spadj
  |  sub rsp, rax
  |
  |  // Copy stack slots.
  |  movzx ecx, byte CCSTATE->nsp
  |  sub ecx, 1
  |  js >2
  |1:
  |  mov rax, [CCSTATE+rcx*8+offsetof(CCallState, stack)]
  |  mov [rsp+rcx*8+CCALL_SPS_EXTRA*8], rax
  |  sub ecx, 1
  |  jns <1
  |2:
  |
  |  movzx eax, byte CCSTATE->nfpr
  |  mov CARG1, CCSTATE->gpr[0]
  |  mov CARG2, CCSTATE->gpr[1]
  |  mov CARG3, CCSTATE->gpr[2]
  |  mov CARG4, CCSTATE->gpr[3]
  |.if not X64WIN
  |  mov CARG5, CCSTATE->gpr[4]
  |  mov CARG6, CCSTATE->gpr[5]
  |.endif
  |  test eax, eax; jz >5
  |  movaps xmm0, CCSTATE->fpr[0]
  |  movaps xmm1, CCSTATE->fpr[1]
  |  movaps xmm2, CCSTATE->fpr[2]
  |  movaps xmm3, CCSTATE->fpr[3]
  |.if not X64WIN
  |  cmp eax, 4; jbe >5
  |  movaps xmm4, CCSTATE->fpr[4]
  |  movaps xmm5, CCSTATE->fpr[5]
  |  movaps xmm6, CCSTATE->fpr[6]
  |  movaps xmm7, CCSTATE->fpr[7]
  |.endif
  |5:
  |
  |  call aword CCSTATE->func
  |
  |  mov CCSTATE->gpr[0], rax
  |  movaps CCSTATE->fpr[0], xmm0
  |.if not X64WIN
  |  mov CCSTATE->gpr[1], rdx
  |  movaps CCSTATE->fpr[1], xmm1
  |.endif
  |
  |  mov rbx, [rbp-8]; leave; ret
  |.endif
  |// Note: vm_ffi_call must be the last function in this object file!
  |
  |//-----------------------------------------------------------------------
}

/* Generate the code for a single instruction. */
static void build_ins(BuildCtx *ctx, BCOp op, int defop)
{
  int vk = 0;
  |// Note: aligning all instructions does not pay off.
  |=>defop:

  switch (op) {

  /* -- Comparison ops ---------------------------------------------------- */

  /* Remember: all ops branch for a true comparison, fall through otherwise. */

  |.macro jmp_comp, lt, ge, le, gt, target
  ||switch (op) {
  ||case BC_ISLT:
  |   lt target
  ||break;
  ||case BC_ISGE:
  |   ge target
  ||break;
  ||case BC_ISLE:
  |   le target
  ||break;
  ||case BC_ISGT:
  |   gt target
  ||break;
  ||default: break;  /* Shut up GCC. */
  ||}
  |.endmacro

  case BC_ISLT: case BC_ISGE: case BC_ISLE: case BC_ISGT:
    |  // RA = src1, RD = src2, JMP with RD = target
    |  ins_AD
    |  mov ITYPE, [BASE+RA*8]
    |  mov RB, [BASE+RD*8]
    |  mov RA, ITYPE
    |  mov RD, RB
    |  sar ITYPE, 47
    |  sar RB, 47
    |.if DUALNUM
    |  cmp ITYPEd, LJ_TISNUM; jne >7
    |  cmp RBd, LJ_TISNUM; jne >8
    |  add PC, 4
    |  cmp RAd, RDd
    |  jmp_comp jge, jl, jg, jle, >9
    |6:
    |  movzx RDd, PC_RD
    |  branchPC RD
    |9:
    |  ins_next
    |
    |7:  // RA is not an integer.
    |  ja ->vmeta_comp
    |  // RA is a number.
    |  cmp RBd, LJ_TISNUM; jb >1; jne ->vmeta_comp
    |  // RA is a number, RD is an integer.
    |  cvtsi2sd xmm0, RDd
    |  jmp >2
    |
    |8:  // RA is an integer, RD is not an integer.
    |  ja ->vmeta_comp
    |  // RA is an integer, RD is a number.
    |  cvtsi2sd xmm1, RAd
    |  movd xmm0, RD
    |  jmp >3
    |.else
    |  cmp ITYPEd, LJ_TISNUM; jae ->vmeta_comp
    |  cmp RBd, LJ_TISNUM; jae ->vmeta_comp
    |.endif
    |1:
    |  movd xmm0, RD
    |2:
    |  movd xmm1, RA
    |3:
    |  add PC, 4
    |  ucomisd xmm0, xmm1
    |  // Unordered: all of ZF CF PF set, ordered: PF clear.
    |  // To preserve NaN semantics GE/GT branch on unordered, but LT/LE don't.
    |.if DUALNUM
    |  jmp_comp jbe, ja, jb, jae, <9
    |  jmp <6
    |.else
    |  jmp_comp jbe, ja, jb, jae, >1
    |  movzx RDd, PC_RD
    |  branchPC RD
    |1:
    |  ins_next
    |.endif
    break;

  case BC_ISEQV: case BC_ISNEV:
    vk = op == BC_ISEQV;
    |  ins_AD   // RA = src1, RD = src2, JMP with RD = target
    |  mov RB, [BASE+RD*8]
    |  mov ITYPE, [BASE+RA*8]
    |  add PC, 4
    |  mov RD, RB
    |  mov RA, ITYPE
    |  sar RB, 47
    |  sar ITYPE, 47
    |.if DUALNUM
    |  cmp RBd, LJ_TISNUM; jne >7
    |  cmp ITYPEd, LJ_TISNUM; jne >8
    |  cmp RDd, RAd
    if (vk) {
      |  jne >9
    } else {
      |  je >9
    }
    |  movzx RDd, PC_RD
    |  branchPC RD
    |9:
    |  ins_next
    |
    |7:  // RD is not an integer.
    |  ja >5
    |  // RD is a number.
    |  movd xmm1, RD
    |  cmp ITYPEd, LJ_TISNUM; jb >1; jne >5
    |  // RD is a number, RA is an integer.
    |  cvtsi2sd xmm0, RAd
    |  jmp >2
    |
    |8:  // RD is an integer, RA is not an integer.
    |  ja >5
    |  // RD is an integer, RA is a number.
    |  cvtsi2sd xmm1, RDd
    |  jmp >1
    |
    |.else
    |  cmp RBd, LJ_TISNUM; jae >5
    |  cmp ITYPEd, LJ_TISNUM; jae >5
    |  movd xmm1, RD
    |.endif
    |1:
    |  movd xmm0, RA
    |2:
    |  ucomisd xmm0, xmm1
    |4:
  iseqne_fp:
    if (vk) {
      |  jp >2                          // Unordered means not equal.
      |  jne >2
    } else {
      |  jp >2                          // Unordered means not equal.
      |  je >1
    }
  iseqne_end:
    if (vk) {
      |1:                               // EQ: Branch to the target.
      |  movzx RDd, PC_RD
      |  branchPC RD
      |2:                               // NE: Fallthrough to next instruction.
      |.if not FFI
      |3:
      |.endif
    } else {
      |.if not FFI
      |3:
      |.endif
      |2:                               // NE: Branch to the target.
      |  movzx RDd, PC_RD
      |  branchPC RD
      |1:                               // EQ: Fallthrough to next instruction.
    }
    if (LJ_DUALNUM && (op == BC_ISEQV || op == BC_ISNEV ||
                       op == BC_ISEQN || op == BC_ISNEN)) {
      |  jmp <9
    } else {
      |  ins_next
    }
    |
    if (op == BC_ISEQV || op == BC_ISNEV) {
      |5:  // Either or both types are not numbers.
      |.if FFI
      |  cmp RBd, LJ_TCDATA; je ->vmeta_equal_cd
      |  cmp ITYPEd, LJ_TCDATA; je ->vmeta_equal_cd
      |.endif
      |  cmp RA, RD
      |  je <1                          // Same GCobjs or pvalues?
      |  cmp RBd, ITYPEd
      |  jne <2                         // Not the same type?
      |  cmp RBd, LJ_TISTABUD
      |  ja <2                          // Different objects and not table/ud?
      |
      |  // Different tables or userdatas. Need to check __eq metamethod.
      |  // Field metatable must be at same offset for GCtab and GCudata!
      |  cleartp TAB:RA
      |  mov TAB:RB, TAB:RA->metatable
      |  test TAB:RB, TAB:RB
      |  jz <2                          // No metatable?
      |  test byte TAB:RB->nomm, 1<<MM_eq
      |  jnz <2                         // Or 'no __eq' flag set?
      if (vk) {
        |  xor RBd, RBd                 // ne = 0
      } else {
        |  mov RBd, 1                   // ne = 1
      }
      |  jmp ->vmeta_equal              // Handle __eq metamethod.
    } else {
      |.if FFI
      |3:
      |  cmp ITYPEd, LJ_TCDATA
      if (LJ_DUALNUM && vk) {
        |  jne <9
      } else {
        |  jne <2
      }
      |  jmp ->vmeta_equal_cd
      |.endif
    }
    break;
  case BC_ISEQS: case BC_ISNES:
    vk = op == BC_ISEQS;
    |  ins_AND  // RA = src, RD = str const, JMP with RD = target
    |  mov RB, [BASE+RA*8]
    |  add PC, 4
    |  checkstr RB, >3
    |  cmp RB, [KBASE+RD*8]
  iseqne_test:
    if (vk) {
      |  jne >2
    } else {
      |  je >1
    }
    goto iseqne_end;
  case BC_ISEQN: case BC_ISNEN:
    vk = op == BC_ISEQN;
    |  ins_AD   // RA = src, RD = num const, JMP with RD = target
    |  mov RB, [BASE+RA*8]
    |  add PC, 4
    |.if DUALNUM
    |  checkint RB, >7
    |  mov RD, [KBASE+RD*8]
    |  checkint RD, >8
    |  cmp RBd, RDd
    if (vk) {
      |  jne >9
    } else {
      |  je >9
    }
    |  movzx RDd, PC_RD
    |  branchPC RD
    |9:
    |  ins_next
    |
    |7:  // RA is not an integer.
    |  ja >3
    |  // RA is a number.
    |  mov RD, [KBASE+RD*8]
    |  checkint RD, >1
    |  // RA is a number, RD is an integer.
    |  cvtsi2sd xmm0, RDd
    |  jmp >2
    |
    |8:  // RA is an integer, RD is a number.
    |  cvtsi2sd xmm0, RBd
    |  movd xmm1, RD
    |  ucomisd xmm0, xmm1
    |  jmp >4
    |1:
    |  movd xmm0, RD
    |.else
    |  checknum RB, >3
    |1:
    |  movsd xmm0, qword [KBASE+RD*8]
    |.endif
    |2:
    |  ucomisd xmm0, qword [BASE+RA*8]
    |4:
    goto iseqne_fp;
  case BC_ISEQP: case BC_ISNEP:
    vk = op == BC_ISEQP;
    |  ins_AND  // RA = src, RD = primitive type (~), JMP with RD = target
    |  mov RB, [BASE+RA*8]
    |  sar RB, 47
    |  add PC, 4
    |  cmp RBd, RDd
    if (!LJ_HASFFI) goto iseqne_test;
    if (vk) {
      |  jne >3
      |  movzx RDd, PC_RD
      |  branchPC RD
      |2:
      |  ins_next
      |3:
      |  cmp RBd, LJ_TCDATA; jne <2
      |  jmp ->vmeta_equal_cd
    } else {
      |  je >2
      |  cmp RBd, LJ_TCDATA; je ->vmeta_equal_cd
      |  movzx RDd, PC_RD
      |  branchPC RD
      |2:
      |  ins_next
    }
    break;

  /* -- Unary test and copy ops ------------------------------------------- */

  case BC_ISTC: case BC_ISFC: case BC_IST: case BC_ISF:
    |  ins_AD   // RA = dst or unused, RD = src, JMP with RD = target
    |  mov ITYPE, [BASE+RD*8]
    |  add PC, 4
    if (op == BC_ISTC || op == BC_ISFC) {
      |  mov RB, ITYPE
    }
    |  sar ITYPE, 47
    |  cmp ITYPEd, LJ_TISTRUECOND
    if (op == BC_IST || op == BC_ISTC) {
      |  jae >1
    } else {
      |  jb >1
    }
    if (op == BC_ISTC || op == BC_ISFC) {
      |  mov [BASE+RA*8], RB
    }
    |  movzx RDd, PC_RD
    |  branchPC RD
    |1:                                 // Fallthrough to the next instruction.
    |  ins_next
    break;

  case BC_ISTYPE:
    |  ins_AD   // RA = src, RD = -type
    |  mov RB, [BASE+RA*8]
    |  sar RB, 47
    |  add RBd, RDd
    |  jne ->vmeta_istype
    |  ins_next
    break;
  case BC_ISNUM:
    |  ins_AD   // RA = src, RD = -(TISNUM-1)
    |  checknumtp [BASE+RA*8], ->vmeta_istype
    |  ins_next
    break;

  /* -- Unary ops --------------------------------------------------------- */

  case BC_MOV:
    |  ins_AD   // RA = dst, RD = src
    |  mov RB, [BASE+RD*8]
    |  mov [BASE+RA*8], RB
    |  ins_next_
    break;
  case BC_NOT:
    |  ins_AD   // RA = dst, RD = src
    |  mov RB, [BASE+RD*8]
    |  sar RB, 47
    |  mov RCd, 2
    |  cmp RB, LJ_TISTRUECOND
    |  sbb RCd, 0
    |  shl RC, 47
    |  not RC
    |  mov [BASE+RA*8], RC
    |  ins_next
    break;
  case BC_UNM:
    |  ins_AD   // RA = dst, RD = src
    |  mov RB, [BASE+RD*8]
    |.if DUALNUM
    |  checkint RB, >5
    |  neg RBd
    |  jo >4
    |  setint RB
    |9:
    |  mov [BASE+RA*8], RB
    |  ins_next
    |4:
    |  mov64 RB, U64x(41e00000,00000000)  // 2^31.
    |  jmp <9
    |5:
    |  ja ->vmeta_unm
    |.else
    |  checknum RB, ->vmeta_unm
    |.endif
    |  mov64 RD, U64x(80000000,00000000)
    |  xor RB, RD
    |.if DUALNUM
    |  jmp <9
    |.else
    |  mov [BASE+RA*8], RB
    |  ins_next
    |.endif
    break;
  case BC_LEN:
    |  ins_AD   // RA = dst, RD = src
    |  mov RD, [BASE+RD*8]
    |  checkstr RD, >2
    |.if DUALNUM
    |  mov RDd, dword STR:RD->len
    |1:
    |  setint RD
    |  mov [BASE+RA*8], RD
    |.else
    |  xorps xmm0, xmm0
    |  cvtsi2sd xmm0, dword STR:RD->len
    |1:
    |  movsd qword [BASE+RA*8], xmm0
    |.endif
    |  ins_next
    |2:
    |  cmp ITYPEd, LJ_TTAB; jne ->vmeta_len
    |  mov TAB:CARG1, TAB:RD
#if LJ_52
    |  mov TAB:RB, TAB:RD->metatable
    |  cmp TAB:RB, 0
    |  jnz >9
    |3:
#endif
    |->BC_LEN_Z:
    |  mov RB, BASE                     // Save BASE.
    |  call extern lj_tab_len           // (GCtab *t)
    |  // Length of table returned in eax (RD).
    |.if DUALNUM
    |  // Nothing to do.
    |.else
    |  cvtsi2sd xmm0, RDd
    |.endif
    |  mov BASE, RB                     // Restore BASE.
    |  movzx RAd, PC_RA
    |  jmp <1
#if LJ_52
    |9:  // Check for __len.
    |  test byte TAB:RB->nomm, 1<<MM_len
    |  jnz <3
    |  jmp ->vmeta_len                  // 'no __len' flag NOT set: check.
#endif
    break;

  /* -- Binary ops -------------------------------------------------------- */

    |.macro ins_arithpre, sseins, ssereg
    |  ins_ABC
    ||vk = ((int)op - BC_ADDVN) / (BC_ADDNV-BC_ADDVN);
    ||switch (vk) {
    ||case 0:
    |   checknumtp [BASE+RB*8], ->vmeta_arith_vn
    |   .if DUALNUM
    |     checknumtp [KBASE+RC*8], ->vmeta_arith_vn
    |   .endif
    |   movsd xmm0, qword [BASE+RB*8]
    |   sseins ssereg, qword [KBASE+RC*8]
    ||  break;
    ||case 1:
    |   checknumtp [BASE+RB*8], ->vmeta_arith_nv
    |   .if DUALNUM
    |     checknumtp [KBASE+RC*8], ->vmeta_arith_nv
    |   .endif
    |   movsd xmm0, qword [KBASE+RC*8]
    |   sseins ssereg, qword [BASE+RB*8]
    ||  break;
    ||default:
    |   checknumtp [BASE+RB*8], ->vmeta_arith_vv
    |   checknumtp [BASE+RC*8], ->vmeta_arith_vv
    |   movsd xmm0, qword [BASE+RB*8]
    |   sseins ssereg, qword [BASE+RC*8]
    ||  break;
    ||}
    |.endmacro
    |
    |.macro ins_arithdn, intins
    |  ins_ABC
    ||vk = ((int)op - BC_ADDVN) / (BC_ADDNV-BC_ADDVN);
    ||switch (vk) {
    ||case 0:
    |   mov RB, [BASE+RB*8]
    |   mov RC, [KBASE+RC*8]
    |   checkint RB, ->vmeta_arith_vno
    |   checkint RC, ->vmeta_arith_vno
    |   intins RBd, RCd; jo ->vmeta_arith_vno
    ||  break;
    ||case 1:
    |   mov RB, [BASE+RB*8]
    |   mov RC, [KBASE+RC*8]
    |   checkint RB, ->vmeta_arith_nvo
    |   checkint RC, ->vmeta_arith_nvo
    |   intins RCd, RBd; jo ->vmeta_arith_nvo
    ||  break;
    ||default:
    |   mov RB, [BASE+RB*8]
    |   mov RC, [BASE+RC*8]
    |   checkint RB, ->vmeta_arith_vvo
    |   checkint RC, ->vmeta_arith_vvo
    |   intins RBd, RCd; jo ->vmeta_arith_vvo
    ||  break;
    ||}
    ||if (vk == 1) {
    |   setint RC
    |   mov [BASE+RA*8], RC
    ||} else {
    |   setint RB
    |   mov [BASE+RA*8], RB
    ||}
    |  ins_next
    |.endmacro
    |
    |.macro ins_arithpost
    |  movsd qword [BASE+RA*8], xmm0
    |.endmacro
    |
    |.macro ins_arith, sseins
    |  ins_arithpre sseins, xmm0
    |  ins_arithpost
    |  ins_next
    |.endmacro
    |
    |.macro ins_arith, intins, sseins
    |.if DUALNUM
    |  ins_arithdn intins
    |.else
    |  ins_arith, sseins
    |.endif
    |.endmacro

    |  // RA = dst, RB = src1 or num const, RC = src2 or num const
  case BC_ADDVN: case BC_ADDNV: case BC_ADDVV:
    |  ins_arith add, addsd
    break;
  case BC_SUBVN: case BC_SUBNV: case BC_SUBVV:
    |  ins_arith sub, subsd
    break;
  case BC_MULVN: case BC_MULNV: case BC_MULVV:
    |  ins_arith imul, mulsd
    break;
  case BC_DIVVN: case BC_DIVNV: case BC_DIVVV:
    |  ins_arith divsd
    break;
  case BC_MODVN:
    |  ins_arithpre movsd, xmm1
    |->BC_MODVN_Z:
    |  call ->vm_mod
    |  ins_arithpost
    |  ins_next
    break;
  case BC_MODNV: case BC_MODVV:
    |  ins_arithpre movsd, xmm1
    |  jmp ->BC_MODVN_Z                 // Avoid 3 copies. It's slow anyway.
    break;
  case BC_POW:
    |  ins_arithpre movsd, xmm1
    |  mov RB, BASE
    |  call extern pow
    |  movzx RAd, PC_RA
    |  mov BASE, RB
    |  ins_arithpost
    |  ins_next
    break;

  case BC_CAT:
    |  ins_ABC  // RA = dst, RB = src_start, RC = src_end
    |  mov L:CARG1, SAVE_L
    |  mov L:CARG1->base, BASE
    |  lea CARG2, [BASE+RC*8]
    |  mov CARG3d, RCd
    |  sub CARG3d, RBd
    |->BC_CAT_Z:
    |  mov L:RB, L:CARG1
    |  mov SAVE_PC, PC
    |  call extern lj_meta_cat          // (lua_State *L, TValue *top, int left)
    |  // NULL (finished) or TValue * (metamethod) returned in eax (RC).
    |  mov BASE, L:RB->base
    |  test RC, RC
    |  jnz ->vmeta_binop
    |  movzx RBd, PC_RB                 // Copy result to Stk[RA] from Stk[RB].
    |  movzx RAd, PC_RA
    |  mov RC, [BASE+RB*8]
    |  mov [BASE+RA*8], RC
    |  ins_next
    break;

  /* -- Constant ops ------------------------------------------------------ */

  case BC_KSTR:
    |  ins_AND  // RA = dst, RD = str const (~)
    |  mov RD, [KBASE+RD*8]
    |  settp RD, LJ_TSTR
    |  mov [BASE+RA*8], RD
    |  ins_next
    break;
  case BC_KCDATA:
    |.if FFI
    |  ins_AND  // RA = dst, RD = cdata const (~)
    |  mov RD, [KBASE+RD*8]
    |  settp RD, LJ_TCDATA
    |  mov [BASE+RA*8], RD
    |  ins_next
    |.endif
    break;
  case BC_KSHORT:
    |  ins_AD   // RA = dst, RD = signed int16 literal
    |.if DUALNUM
    |  movsx RDd, RDW
    |  setint RD
    |  mov [BASE+RA*8], RD
    |.else
    |  movsx RDd, RDW                   // Sign-extend literal.
    |  cvtsi2sd xmm0, RDd
    |  movsd qword [BASE+RA*8], xmm0
    |.endif
    |  ins_next
    break;
  case BC_KNUM:
    |  ins_AD   // RA = dst, RD = num const
    |  movsd xmm0, qword [KBASE+RD*8]
    |  movsd qword [BASE+RA*8], xmm0
    |  ins_next
    break;
  case BC_KPRI:
    |  ins_AD   // RA = dst, RD = primitive type (~)
    |  shl RD, 47
    |  not RD
    |  mov [BASE+RA*8], RD
    |  ins_next
    break;
  case BC_KNIL:
    |  ins_AD   // RA = dst_start, RD = dst_end
    |  lea RA, [BASE+RA*8+8]
    |  lea RD, [BASE+RD*8]
    |  mov RB, LJ_TNIL
    |  mov [RA-8], RB                   // Sets minimum 2 slots.
    |1:
    |  mov [RA], RB
    |  add RA, 8
    |  cmp RA, RD
    |  jbe <1
    |  ins_next
    break;

  /* -- Upvalue and function ops ------------------------------------------ */

  case BC_UGET:
    |  ins_AD   // RA = dst, RD = upvalue #
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov UPVAL:RB, [LFUNC:RB+RD*8+offsetof(GCfuncL, uvptr)]
    |  mov RB, UPVAL:RB->v
    |  mov RD, [RB]
    |  mov [BASE+RA*8], RD
    |  ins_next
    break;
  case BC_USETV:
#define TV2MARKOFS \
 ((int32_t)offsetof(GCupval, marked)-(int32_t)offsetof(GCupval, tv))
    |  ins_AD   // RA = upvalue #, RD = src
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov UPVAL:RB, [LFUNC:RB+RA*8+offsetof(GCfuncL, uvptr)]
    |  cmp byte UPVAL:RB->closed, 0
    |  mov RB, UPVAL:RB->v
    |  mov RA, [BASE+RD*8]
    |  mov [RB], RA
    |  jz >1
    |  // Check barrier for closed upvalue.
    |  test byte [RB+TV2MARKOFS], LJ_GC_BLACK           // isblack(uv)
    |  jnz >2
    |1:
    |  ins_next
    |
    |2:  // Upvalue is black. Check if new value is collectable and white.
    |  mov RD, RA
    |  sar RD, 47
    |  sub RDd, LJ_TISGCV
    |  cmp RDd, LJ_TNUMX - LJ_TISGCV                    // tvisgcv(v)
    |  jbe <1
    |  cleartp GCOBJ:RA
    |  test byte GCOBJ:RA->gch.marked, LJ_GC_WHITES     // iswhite(v)
    |  jz <1
    |  // Crossed a write barrier. Move the barrier forward.
    |.if not X64WIN
    |  mov CARG2, RB
    |  mov RB, BASE                     // Save BASE.
    |.else
    |  xchg CARG2, RB                   // Save BASE (CARG2 == BASE).
    |.endif
    |  lea GL:CARG1, [DISPATCH+GG_DISP2G]
    |  call extern lj_gc_barrieruv      // (global_State *g, TValue *tv)
    |  mov BASE, RB                     // Restore BASE.
    |  jmp <1
    break;
#undef TV2MARKOFS
  case BC_USETS:
    |  ins_AND  // RA = upvalue #, RD = str const (~)
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov UPVAL:RB, [LFUNC:RB+RA*8+offsetof(GCfuncL, uvptr)]
    |  mov STR:RA, [KBASE+RD*8]
    |  mov RD, UPVAL:RB->v
    |  settp STR:ITYPE, STR:RA, LJ_TSTR
    |  mov [RD], STR:ITYPE
    |  test byte UPVAL:RB->marked, LJ_GC_BLACK          // isblack(uv)
    |  jnz >2
    |1:
    |  ins_next
    |
    |2:  // Check if string is white and ensure upvalue is closed.
    |  test byte GCOBJ:RA->gch.marked, LJ_GC_WHITES     // iswhite(str)
    |  jz <1
    |  cmp byte UPVAL:RB->closed, 0
    |  jz <1
    |  // Crossed a write barrier. Move the barrier forward.
    |  mov RB, BASE                     // Save BASE (CARG2 == BASE).
    |  mov CARG2, RD
    |  lea GL:CARG1, [DISPATCH+GG_DISP2G]
    |  call extern lj_gc_barrieruv      // (global_State *g, TValue *tv)
    |  mov BASE, RB                     // Restore BASE.
    |  jmp <1
    break;
  case BC_USETN:
    |  ins_AD   // RA = upvalue #, RD = num const
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  movsd xmm0, qword [KBASE+RD*8]
    |  mov UPVAL:RB, [LFUNC:RB+RA*8+offsetof(GCfuncL, uvptr)]
    |  mov RA, UPVAL:RB->v
    |  movsd qword [RA], xmm0
    |  ins_next
    break;
  case BC_USETP:
    |  ins_AD   // RA = upvalue #, RD = primitive type (~)
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov UPVAL:RB, [LFUNC:RB+RA*8+offsetof(GCfuncL, uvptr)]
    |  shl RD, 47
    |  not RD
    |  mov RA, UPVAL:RB->v
    |  mov [RA], RD
    |  ins_next
    break;
  case BC_UCLO:
    |  ins_AD   // RA = level, RD = target
    |  branchPC RD                      // Do this first to free RD.
    |  mov L:RB, SAVE_L
    |  cmp dword L:RB->openupval, 0
    |  je >1
    |  mov L:RB->base, BASE
    |  lea CARG2, [BASE+RA*8]           // Caveat: CARG2 == BASE
    |  mov L:CARG1, L:RB                // Caveat: CARG1 == RA
    |  call extern lj_func_closeuv      // (lua_State *L, TValue *level)
    |  mov BASE, L:RB->base
    |1:
    |  ins_next
    break;

  case BC_FNEW:
    |  ins_AND  // RA = dst, RD = proto const (~) (holding function prototype)
    |  mov L:RB, SAVE_L
    |  mov L:RB->base, BASE             // Caveat: CARG2/CARG3 may be BASE.
    |  mov CARG3, [BASE-16]
    |  cleartp CARG3
    |  mov CARG2, [KBASE+RD*8]          // Fetch GCproto *.
    |  mov CARG1, L:RB
    |  mov SAVE_PC, PC
    |  // (lua_State *L, GCproto *pt, GCfuncL *parent)
    |  call extern lj_func_newL_gc
    |  // GCfuncL * returned in eax (RC).
    |  mov BASE, L:RB->base
    |  movzx RAd, PC_RA
    |  settp LFUNC:RC, LJ_TFUNC
    |  mov [BASE+RA*8], LFUNC:RC
    |  ins_next
    break;

  /* -- Table ops --------------------------------------------------------- */

  case BC_TNEW:
    |  ins_AD   // RA = dst, RD = hbits|asize
    |  mov L:RB, SAVE_L
    |  mov L:RB->base, BASE
    |  mov RA, [DISPATCH+DISPATCH_GL(gc.total)]
    |  cmp RA, [DISPATCH+DISPATCH_GL(gc.threshold)]
    |  mov SAVE_PC, PC
    |  jae >5
    |1:
    |  mov CARG3d, RDd
    |  and RDd, 0x7ff
    |  shr CARG3d, 11
    |  cmp RDd, 0x7ff
    |  je >3
    |2:
    |  mov L:CARG1, L:RB
    |  mov CARG2d, RDd
    |  call extern lj_tab_new  // (lua_State *L, int32_t asize, uint32_t hbits)
    |  // Table * returned in eax (RC).
    |  mov BASE, L:RB->base
    |  movzx RAd, PC_RA
    |  settp TAB:RC, LJ_TTAB
    |  mov [BASE+RA*8], TAB:RC
    |  ins_next
    |3:  // Turn 0x7ff into 0x801.
    |  mov RDd, 0x801
    |  jmp <2
    |5:
    |  mov L:CARG1, L:RB
    |  call extern lj_gc_step_fixtop    // (lua_State *L)
    |  movzx RDd, PC_RD
    |  jmp <1
    break;
  case BC_TDUP:
    |  ins_AND  // RA = dst, RD = table const (~) (holding template table)
    |  mov L:RB, SAVE_L
    |  mov RA, [DISPATCH+DISPATCH_GL(gc.total)]
    |  mov SAVE_PC, PC
    |  cmp RA, [DISPATCH+DISPATCH_GL(gc.threshold)]
    |  mov L:RB->base, BASE
    |  jae >3
    |2:
    |  mov TAB:CARG2, [KBASE+RD*8]      // Caveat: CARG2 == BASE
    |  mov L:CARG1, L:RB                // Caveat: CARG1 == RA
    |  call extern lj_tab_dup           // (lua_State *L, Table *kt)
    |  // Table * returned in eax (RC).
    |  mov BASE, L:RB->base
    |  movzx RAd, PC_RA
    |  settp TAB:RC, LJ_TTAB
    |  mov [BASE+RA*8], TAB:RC
    |  ins_next
    |3:
    |  mov L:CARG1, L:RB
    |  call extern lj_gc_step_fixtop    // (lua_State *L)
    |  movzx RDd, PC_RD                 // Need to reload RD.
    |  not RD
    |  jmp <2
    break;

  case BC_GGET:
    |  ins_AND  // RA = dst, RD = str const (~)
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov TAB:RB, LFUNC:RB->env
    |  mov STR:RC, [KBASE+RD*8]
    |  jmp ->BC_TGETS_Z
    break;
  case BC_GSET:
    |  ins_AND  // RA = src, RD = str const (~)
    |  mov LFUNC:RB, [BASE-16]
    |  cleartp LFUNC:RB
    |  mov TAB:RB, LFUNC:RB->env
    |  mov STR:RC, [KBASE+RD*8]
    |  jmp ->BC_TSETS_Z
    break;

  case BC_TGETV:
    |  ins_ABC  // RA = dst, RB = table, RC = key
    |  mov TAB:RB, [BASE+RB*8]
    |  mov RC, [BASE+RC*8]
    |  checktab TAB:RB, ->vmeta_tgetv
    |
    |  // Integer key?
    |.if DUALNUM
    |  checkint RC, >5
    |.else
    |  // Convert number to int and back and compare.
    |  checknum RC, >5
    |  movd xmm0, RC
    |  cvttsd2si RCd, xmm0
    |  cvtsi2sd xmm1, RCd
    |  ucomisd xmm0, xmm1
    |  jne ->vmeta_tgetv                // Generic numeric key? Use fallback.
    |.endif
    |  cmp RCd, TAB:RB->asize           // Takes care of unordered, too.
    |  jae ->vmeta_tgetv                // Not in array part? Use fallback.
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  // Get array slot.
    |  mov ITYPE, [RC]
    |  cmp ITYPE, LJ_TNIL               // Avoid overwriting RB in fastpath.
    |  je >2
    |1:
    |  mov [BASE+RA*8], ITYPE
    |  ins_next
    |
    |2:  // Check for __index if table value is nil.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz <1
    |  test byte TAB:TMPR->nomm, 1<<MM_index
    |  jz ->vmeta_tgetv                 // 'no __index' flag NOT set: check.
    |  jmp <1
    |
    |5:  // String key?
    |  cmp ITYPEd, LJ_TSTR; jne ->vmeta_tgetv
    |  cleartp STR:RC
    |  jmp ->BC_TGETS_Z
    break;
  case BC_TGETS:
    |  ins_ABC  // RA = dst, RB = table, RC = str const (~)
    |  mov TAB:RB, [BASE+RB*8]
    |  not RC
    |  mov STR:RC, [KBASE+RC*8]
    |  checktab TAB:RB, ->vmeta_tgets
    |->BC_TGETS_Z:      // RB = GCtab *, RC = GCstr *
    |  mov TMPRd, TAB:RB->hmask
    |  and TMPRd, STR:RC->hash
    |  imul TMPRd, #NODE
    |  add NODE:TMPR, TAB:RB->node
    |  settp ITYPE, STR:RC, LJ_TSTR
    |1:
    |  cmp NODE:TMPR->key, ITYPE
    |  jne >4
    |  // Get node value.
    |  mov ITYPE, NODE:TMPR->val
    |  cmp ITYPE, LJ_TNIL
    |  je >5                            // Key found, but nil value?
    |2:
    |  mov [BASE+RA*8], ITYPE
    |  ins_next
    |
    |4:  // Follow hash chain.
    |  mov NODE:TMPR, NODE:TMPR->next
    |  test NODE:TMPR, NODE:TMPR
    |  jnz <1
    |  // End of hash chain: key not found, nil result.
    |  mov ITYPE, LJ_TNIL
    |
    |5:  // Check for __index if table value is nil.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz <2                            // No metatable: done.
    |  test byte TAB:TMPR->nomm, 1<<MM_index
    |  jnz <2                           // 'no __index' flag set: done.
    |  jmp ->vmeta_tgets                // Caveat: preserve STR:RC.
    break;
  case BC_TGETB:
    |  ins_ABC  // RA = dst, RB = table, RC = byte literal
    |  mov TAB:RB, [BASE+RB*8]
    |  checktab TAB:RB, ->vmeta_tgetb
    |  cmp RCd, TAB:RB->asize
    |  jae ->vmeta_tgetb
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  // Get array slot.
    |  mov ITYPE, [RC]
    |  cmp ITYPE, LJ_TNIL
    |  je >2
    |1:
    |  mov [BASE+RA*8], ITYPE
    |  ins_next
    |
    |2:  // Check for __index if table value is nil.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz <1
    |  test byte TAB:TMPR->nomm, 1<<MM_index
    |  jz ->vmeta_tgetb                 // 'no __index' flag NOT set: check.
    |  jmp <1
    break;
  case BC_TGETR:
    |  ins_ABC  // RA = dst, RB = table, RC = key
    |  mov TAB:RB, [BASE+RB*8]
    |  cleartp TAB:RB
    |.if DUALNUM
    |  mov RCd, dword [BASE+RC*8]
    |.else
    |  cvttsd2si RCd, qword [BASE+RC*8]
    |.endif
    |  cmp RCd, TAB:RB->asize
    |  jae ->vmeta_tgetr                // Not in array part? Use fallback.
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  // Get array slot.
    |->BC_TGETR_Z:
    |  mov ITYPE, [RC]
    |->BC_TGETR2_Z:
    |  mov [BASE+RA*8], ITYPE
    |  ins_next
    break;

  case BC_TSETV:
    |  ins_ABC  // RA = src, RB = table, RC = key
    |  mov TAB:RB, [BASE+RB*8]
    |  mov RC, [BASE+RC*8]
    |  checktab TAB:RB, ->vmeta_tsetv
    |
    |  // Integer key?
    |.if DUALNUM
    |  checkint RC, >5
    |.else
    |  // Convert number to int and back and compare.
    |  checknum RC, >5
    |  movd xmm0, RC
    |  cvttsd2si RCd, xmm0
    |  cvtsi2sd xmm1, RCd
    |  ucomisd xmm0, xmm1
    |  jne ->vmeta_tsetv                // Generic numeric key? Use fallback.
    |.endif
    |  cmp RCd, TAB:RB->asize           // Takes care of unordered, too.
    |  jae ->vmeta_tsetv
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  cmp aword [RC], LJ_TNIL
    |  je >3                            // Previous value is nil?
    |1:
    |  test byte TAB:RB->marked, LJ_GC_BLACK    // isblack(table)
    |  jnz >7
    |2:  // Set array slot.
    |  mov RB, [BASE+RA*8]
    |  mov [RC], RB
    |  ins_next
    |
    |3:  // Check for __newindex if previous value is nil.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz <1
    |  test byte TAB:TMPR->nomm, 1<<MM_newindex
    |  jz ->vmeta_tsetv                 // 'no __newindex' flag NOT set: check.
    |  jmp <1
    |
    |5:  // String key?
    |  cmp ITYPEd, LJ_TSTR; jne ->vmeta_tsetv
    |  cleartp STR:RC
    |  jmp ->BC_TSETS_Z
    |
    |7:  // Possible table write barrier for the value. Skip valiswhite check.
    |  barrierback TAB:RB, TMPR
    |  jmp <2
    break;
  case BC_TSETS:
    |  ins_ABC  // RA = src, RB = table, RC = str const (~)
    |  mov TAB:RB, [BASE+RB*8]
    |  not RC
    |  mov STR:RC, [KBASE+RC*8]
    |  checktab TAB:RB, ->vmeta_tsets
    |->BC_TSETS_Z:      // RB = GCtab *, RC = GCstr *
    |  mov TMPRd, TAB:RB->hmask
    |  and TMPRd, STR:RC->hash
    |  imul TMPRd, #NODE
    |  mov byte TAB:RB->nomm, 0         // Clear metamethod cache.
    |  add NODE:TMPR, TAB:RB->node
    |  settp ITYPE, STR:RC, LJ_TSTR
    |1:
    |  cmp NODE:TMPR->key, ITYPE
    |  jne >5
    |  // Ok, key found. Assumes: offsetof(Node, val) == 0
    |  cmp aword [TMPR], LJ_TNIL
    |  je >4                            // Previous value is nil?
    |2:
    |  test byte TAB:RB->marked, LJ_GC_BLACK    // isblack(table)
    |  jnz >7
    |3:  // Set node value.
    |  mov ITYPE, [BASE+RA*8]
    |  mov [TMPR], ITYPE
    |  ins_next
    |
    |4:  // Check for __newindex if previous value is nil.
    |  mov TAB:ITYPE, TAB:RB->metatable
    |  test TAB:ITYPE, TAB:ITYPE
    |  jz <2
    |  test byte TAB:ITYPE->nomm, 1<<MM_newindex
    |  jz ->vmeta_tsets                 // 'no __newindex' flag NOT set: check.
    |  jmp <2
    |
    |5:  // Follow hash chain.
    |  mov NODE:TMPR, NODE:TMPR->next
    |  test NODE:TMPR, NODE:TMPR
    |  jnz <1
    |  // End of hash chain: key not found, add a new one.
    |
    |  // But check for __newindex first.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz >6                            // No metatable: continue.
    |  test byte TAB:TMPR->nomm, 1<<MM_newindex
    |  jz ->vmeta_tsets                 // 'no __newindex' flag NOT set: check.
    |6:
    |  mov TMP1, ITYPE
    |  mov L:CARG1, SAVE_L
    |  mov L:CARG1->base, BASE
    |  lea CARG3, TMP1
    |  mov CARG2, TAB:RB
    |  mov SAVE_PC, PC
    |  call extern lj_tab_newkey        // (lua_State *L, GCtab *t, TValue *k)
    |  // Handles write barrier for the new key. TValue * returned in eax (RC).
    |  mov L:CARG1, SAVE_L
    |  mov BASE, L:CARG1->base
    |  mov TMPR, rax
    |  movzx RAd, PC_RA
    |  jmp <2                           // Must check write barrier for value.
    |
    |7:  // Possible table write barrier for the value. Skip valiswhite check.
    |  barrierback TAB:RB, ITYPE
    |  jmp <3
    break;
  case BC_TSETB:
    |  ins_ABC  // RA = src, RB = table, RC = byte literal
    |  mov TAB:RB, [BASE+RB*8]
    |  checktab TAB:RB, ->vmeta_tsetb
    |  cmp RCd, TAB:RB->asize
    |  jae ->vmeta_tsetb
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  cmp aword [RC], LJ_TNIL
    |  je >3                            // Previous value is nil?
    |1:
    |  test byte TAB:RB->marked, LJ_GC_BLACK    // isblack(table)
    |  jnz >7
    |2:  // Set array slot.
    |  mov ITYPE, [BASE+RA*8]
    |  mov [RC], ITYPE
    |  ins_next
    |
    |3:  // Check for __newindex if previous value is nil.
    |  mov TAB:TMPR, TAB:RB->metatable
    |  test TAB:TMPR, TAB:TMPR
    |  jz <1
    |  test byte TAB:TMPR->nomm, 1<<MM_newindex
    |  jz ->vmeta_tsetb                 // 'no __newindex' flag NOT set: check.
    |  jmp <1
    |
    |7:  // Possible table write barrier for the value. Skip valiswhite check.
    |  barrierback TAB:RB, TMPR
    |  jmp <2
    break;
  case BC_TSETR:
    |  ins_ABC  // RA = src, RB = table, RC = key
    |  mov TAB:RB, [BASE+RB*8]
    |  cleartp TAB:RB
    |.if DUALNUM
    |  mov RC, [BASE+RC*8]
    |.else
    |  cvttsd2si RCd, qword [BASE+RC*8]
    |.endif
    |  test byte TAB:RB->marked, LJ_GC_BLACK    // isblack(table)
    |  jnz >7
    |2:
    |  cmp RCd, TAB:RB->asize
    |  jae ->vmeta_tsetr
    |  shl RCd, 3
    |  add RC, TAB:RB->array
    |  // Set array slot.
    |->BC_TSETR_Z:
    |  mov ITYPE, [BASE+RA*8]
    |  mov [RC], ITYPE
    |  ins_next
    |
    |7:  // Possible table write barrier for the value. Skip valiswhite check.
    |  barrierback TAB:RB, TMPR
    |  jmp <2
    break;

  case BC_TSETM:
    |  ins_AD   // RA = base (table at base-1), RD = num const (start index)
    |1:
    |  mov TMPRd, dword [KBASE+RD*8]    // Integer constant is in lo-word.
    |  lea RA, [BASE+RA*8]
    |  mov TAB:RB, [RA-8]               // Guaranteed to be a table.
    |  cleartp TAB:RB
    |  test byte TAB:RB->marked, LJ_GC_BLACK    // isblack(table)
    |  jnz >7
    |2:
    |  mov RDd, MULTRES
    |  sub RDd, 1
    |  jz >4                            // Nothing to copy?
    |  add RDd, TMPRd                   // Compute needed size.
    |  cmp RDd, TAB:RB->asize
    |  ja >5                            // Doesn't fit into array part?
    |  sub RDd, TMPRd
    |  shl TMPRd, 3
    |  add TMPR, TAB:RB->array
    |3:  // Copy result slots to table.
    |  mov RB, [RA]
    |  add RA, 8
    |  mov [TMPR], RB
    |  add TMPR, 8
    |  sub RDd, 1
    |  jnz <3
    |4:
    |  ins_next
    |
    |5:  // Need to resize array part.
    |  mov L:CARG1, SAVE_L
    |  mov L:CARG1->base, BASE          // Caveat: CARG2/CARG3 may be BASE.
    |  mov CARG2, TAB:RB
    |  mov CARG3d, RDd
    |  mov L:RB, L:CARG1
    |  mov SAVE_PC, PC
    |  call extern lj_tab_reasize       // (lua_State *L, GCtab *t, int nasize)
    |  mov BASE, L:RB->base
    |  movzx RAd, PC_RA                 // Restore RA.
    |  movzx RDd, PC_RD                 // Restore RD.
    |  jmp <1                           // Retry.
    |
    |7:  // Possible table write barrier for any value. Skip valiswhite check.
    |  barrierback TAB:RB, RD
    |  jmp <2
    break;

  /* -- Calls and vararg handling ----------------------------------------- */

  case BC_CALL: case BC_CALLM:
    |  ins_A_C  // RA = base, (RB = nresults+1,) RC = nargs+1 | extra_nargs
    if (op == BC_CALLM) {
      |  add NARGS:RDd, MULTRES
    }
    |  mov LFUNC:RB, [BASE+RA*8]
    |  checkfunc LFUNC:RB, ->vmeta_call_ra
    |  lea BASE, [BASE+RA*8+16]
    |  ins_call
    break;

  case BC_CALLMT:
    |  ins_AD   // RA = base, RD = extra_nargs
    |  add NARGS:RDd, MULTRES
    |  // Fall through. Assumes BC_CALLT follows and ins_AD is a no-op.
    break;
  case BC_CALLT:
    |  ins_AD   // RA = base, RD = nargs+1
    |  lea RA, [BASE+RA*8+16]
    |  mov KBASE, BASE                  // Use KBASE for move + vmeta_call hint.
    |  mov LFUNC:RB, [RA-16]
    |  checktp_nc LFUNC:RB, LJ_TFUNC, ->vmeta_call
    |->BC_CALLT_Z:
    |  mov PC, [BASE-8]
    |  test PCd, FRAME_TYPE
    |  jnz >7
    |1:
    |  mov [BASE-16], LFUNC:RB          // Copy func+tag down, reloaded below.
    |  mov MULTRES, NARGS:RDd
    |  sub NARGS:RDd, 1
    |  jz >3
    |2:  // Move args down.
    |  mov RB, [RA]
    |  add RA, 8
    |  mov [KBASE], RB
    |  add KBASE, 8
    |  sub NARGS:RDd, 1
    |  jnz <2
    |
    |  mov LFUNC:RB, [BASE-16]
    |3:
    |  cleartp LFUNC:RB
    |  mov NARGS:RDd, MULTRES
    |  cmp byte LFUNC:RB->ffid, 1       // (> FF_C) Calling a fast function?
    |  ja >5
    |4:
    |  ins_callt
    |
    |5:  // Tailcall to a fast function.
    |  test PCd, FRAME_TYPE             // Lua frame below?
    |  jnz <4
    |  movzx RAd, PC_RA
    |  neg RA
    |  mov LFUNC:KBASE, [BASE+RA*8-32]  // Need to prepare KBASE.
    |  cleartp LFUNC:KBASE
    |  mov KBASE, LFUNC:KBASE->pc
    |  mov KBASE, [KBASE+PC2PROTO(k)]
    |  jmp <4
    |
    |7:  // Tailcall from a vararg function.
    |  sub PC, FRAME_VARG
    |  test PCd, FRAME_TYPEP
    |  jnz >8                           // Vararg frame below?
    |  sub BASE, PC                     // Need to relocate BASE/KBASE down.
    |  mov KBASE, BASE
    |  mov PC, [BASE-8]
    |  jmp <1
    |8:
    |  add PCd, FRAME_VARG
    |  jmp <1
    break;

  case BC_ITERC:
    |  ins_A    // RA = base, (RB = nresults+1,) RC = nargs+1 (2+1)
    |  lea RA, [BASE+RA*8+16]           // fb = base+2
    |  mov RB, [RA-32]                  // Copy state. fb[0] = fb[-4].
    |  mov RC, [RA-24]                  // Copy control var. fb[1] = fb[-3].
    |  mov [RA], RB
    |  mov [RA+8], RC
    |  mov LFUNC:RB, [RA-40]            // Copy callable. fb[-1] = fb[-5]
    |  mov [RA-16], LFUNC:RB
    |  mov NARGS:RDd, 2+1               // Handle like a regular 2-arg call.
    |  checkfunc LFUNC:RB, ->vmeta_call
    |  mov BASE, RA
    |  ins_call
    break;

  case BC_ITERN:
    |  ins_A    // RA = base, (RB = nresults+1, RC = nargs+1 (2+1))
    |.if JIT
    |  // NYI: add hotloop, record BC_ITERN.
    |.endif
    |  mov TAB:RB, [BASE+RA*8-16]
    |  cleartp TAB:RB
    |  mov RCd, [BASE+RA*8-8]           // Get index from control var.
    |  mov TMPRd, TAB:RB->asize
    |  add PC, 4
    |  mov ITYPE, TAB:RB->array
    |1:  // Traverse array part.
    |  cmp RCd, TMPRd; jae >5           // Index points after array part?
    |  cmp aword [ITYPE+RC*8], LJ_TNIL; je >4
    |.if not DUALNUM
    |  cvtsi2sd xmm0, RCd
    |.endif
    |  // Copy array slot to returned value.
    |  mov RB, [ITYPE+RC*8]
    |  mov [BASE+RA*8+8], RB
    |  // Return array index as a numeric key.
    |.if DUALNUM
    |  setint ITYPE, RC
    |  mov [BASE+RA*8], ITYPE
    |.else
    |  movsd qword [BASE+RA*8], xmm0
    |.endif
    |  add RCd, 1
    |  mov [BASE+RA*8-8], RCd           // Update control var.
    |2:
    |  movzx RDd, PC_RD                 // Get target from ITERL.
    |  branchPC RD
    |3:
    |  ins_next
    |
    |4:  // Skip holes in array part.
    |  add RCd, 1
    |  jmp <1
    |
    |5:  // Traverse hash part.
    |  sub RCd, TMPRd
    |6:
    |  cmp RCd, TAB:RB->hmask; ja <3    // End of iteration? Branch to ITERL+1.
    |  imul ITYPEd, RCd, #NODE
    |  add NODE:ITYPE, TAB:RB->node
    |  cmp aword NODE:ITYPE->val, LJ_TNIL; je >7
    |  lea TMPRd, [RCd+TMPRd+1]
    |  // Copy key and value from hash slot.
    |  mov RB, NODE:ITYPE->key
    |  mov RC, NODE:ITYPE->val
    |  mov [BASE+RA*8], RB
    |  mov [BASE+RA*8+8], RC
    |  mov [BASE+RA*8-8], TMPRd
    |  jmp <2
    |
    |7:  // Skip holes in hash part.
    |  add RCd, 1
    |  jmp <6
    break;

  case BC_ISNEXT:
    |  ins_AD   // RA = base, RD = target (points to ITERN)
    |  mov CFUNC:RB, [BASE+RA*8-24]
    |  checkfunc CFUNC:RB, >5
    |  checktptp [BASE+RA*8-16], LJ_TTAB, >5
    |  cmp aword [BASE+RA*8-8], LJ_TNIL; jne >5
    |  cmp byte CFUNC:RB->ffid, FF_next_N; jne >5
    |  branchPC RD
    |  mov64 TMPR, U64x(fffe7fff, 00000000)
    |  mov [BASE+RA*8-8], TMPR          // Initialize control var.
    |1:
    |  ins_next
    |5:  // Despecialize bytecode if any of the checks fail.
    |  mov PC_OP, BC_JMP
    |  branchPC RD
    |  mov byte [PC], BC_ITERC
    |  jmp <1
    break;

  case BC_VARG:
    |  ins_ABC  // RA = base, RB = nresults+1, RC = numparams
    |  lea TMPR, [BASE+RC*8+(16+FRAME_VARG)]
    |  lea RA, [BASE+RA*8]
    |  sub TMPR, [BASE-8]
    |  // Note: TMPR may now be even _above_ BASE if nargs was < numparams.
    |  test RB, RB
    |  jz >5                            // Copy all varargs?
    |  lea RB, [RA+RB*8-8]
    |  cmp TMPR, BASE                   // No vararg slots?
    |  jnb >2
    |1:  // Copy vararg slots to destination slots.
    |  mov RC, [TMPR-16]
    |  add TMPR, 8
    |  mov [RA], RC
    |  add RA, 8
    |  cmp RA, RB                       // All destination slots filled?
    |  jnb >3
    |  cmp TMPR, BASE                   // No more vararg slots?
    |  jb <1
    |2:  // Fill up remainder with nil.
    |  mov aword [RA], LJ_TNIL
    |  add RA, 8
    |  cmp RA, RB
    |  jb <2
    |3:
    |  ins_next
    |
    |5:  // Copy all varargs.
    |  mov MULTRES, 1                   // MULTRES = 0+1
    |  mov RC, BASE
    |  sub RC, TMPR
    |  jbe <3                           // No vararg slots?
    |  mov RBd, RCd
    |  shr RBd, 3
    |  add RBd, 1
    |  mov MULTRES, RBd                 // MULTRES = #varargs+1
    |  mov L:RB, SAVE_L
    |  add RC, RA
    |  cmp RC, L:RB->maxstack
    |  ja >7                            // Need to grow stack?
    |6:  // Copy all vararg slots.
    |  mov RC, [TMPR-16]
    |  add TMPR, 8
    |  mov [RA], RC
    |  add RA, 8
    |  cmp TMPR, BASE                   // No more vararg slots?
    |  jb <6
    |  jmp <3
    |
    |7:  // Grow stack for varargs.
    |  mov L:RB->base, BASE
    |  mov L:RB->top, RA
    |  mov SAVE_PC, PC
    |  sub TMPR, BASE                   // Need delta, because BASE may change.
    |  mov TMP1hi, TMPRd
    |  mov CARG2d, MULTRES
    |  sub CARG2d, 1
    |  mov CARG1, L:RB
    |  call extern lj_state_growstack   // (lua_State *L, int n)
    |  mov BASE, L:RB->base
    |  movsxd TMPR, TMP1hi
    |  mov RA, L:RB->top
    |  add TMPR, BASE
    |  jmp <6
    break;

  /* -- Returns ----------------------------------------------------------- */

  case BC_RETM:
    |  ins_AD   // RA = results, RD = extra_nresults
    |  add RDd, MULTRES                 // MULTRES >=1, so RD >=1.
    |  // Fall through. Assumes BC_RET follows and ins_AD is a no-op.
    break;

  case BC_RET: case BC_RET0: case BC_RET1:
    |  ins_AD   // RA = results, RD = nresults+1
    if (op != BC_RET0) {
      |  shl RAd, 3
    }
    |1:
    |  mov PC, [BASE-8]
    |  mov MULTRES, RDd                 // Save nresults+1.
    |  test PCd, FRAME_TYPE             // Check frame type marker.
    |  jnz >7                           // Not returning to a fixarg Lua func?
    switch (op) {
    case BC_RET:
      |->BC_RET_Z:
      |  mov KBASE, BASE                // Use KBASE for result move.
      |  sub RDd, 1
      |  jz >3
      |2:  // Move results down.
      |  mov RB, [KBASE+RA]
      |  mov [KBASE-16], RB
      |  add KBASE, 8
      |  sub RDd, 1
      |  jnz <2
      |3:
      |  mov RDd, MULTRES               // Note: MULTRES may be >255.
      |  movzx RBd, PC_RB               // So cannot compare with RDL!
      |5:
      |  cmp RBd, RDd                   // More results expected?
      |  ja >6
      break;
    case BC_RET1:
      |  mov RB, [BASE+RA]
      |  mov [BASE-16], RB
      /* fallthrough */
    case BC_RET0:
      |5:
      |  cmp PC_RB, RDL                 // More results expected?
      |  ja >6
    default:
      break;
    }
    |  movzx RAd, PC_RA
    |  neg RA
    |  lea BASE, [BASE+RA*8-16]         // base = base - (RA+2)*8
    |  mov LFUNC:KBASE, [BASE-16]
    |  cleartp LFUNC:KBASE
    |  mov KBASE, LFUNC:KBASE->pc
    |  mov KBASE, [KBASE+PC2PROTO(k)]
    |  ins_next
    |
    |6:  // Fill up results with nil.
    if (op == BC_RET) {
      |  mov aword [KBASE-16], LJ_TNIL  // Note: relies on shifted base.
      |  add KBASE, 8
    } else {
      |  mov aword [BASE+RD*8-24], LJ_TNIL
    }
    |  add RD, 1
    |  jmp <5
    |
    |7:  // Non-standard return case.
    |  lea RB, [PC-FRAME_VARG]
    |  test RBd, FRAME_TYPEP
    |  jnz ->vm_return
    |  // Return from vararg function: relocate BASE down and RA up.
    |  sub BASE, RB
    if (op != BC_RET0) {
      |  add RA, RB
    }
    |  jmp <1
    break;

  /* -- Loops and branches ------------------------------------------------ */

  |.define FOR_IDX,  [RA]
  |.define FOR_STOP, [RA+8]
  |.define FOR_STEP, [RA+16]
  |.define FOR_EXT,  [RA+24]

  case BC_FORL:
    |.if JIT
    |  hotloop RBd
    |.endif
    | // Fall through. Assumes BC_IFORL follows and ins_AJ is a no-op.
    break;

  case BC_JFORI:
  case BC_JFORL:
#if !LJ_HASJIT
    break;
#endif
  case BC_FORI:
  case BC_IFORL:
    vk = (op == BC_IFORL || op == BC_JFORL);
    |  ins_AJ   // RA = base, RD = target (after end of loop or start of loop)
    |  lea RA, [BASE+RA*8]
    if (LJ_DUALNUM) {
      |  mov RB, FOR_IDX
      |  checkint RB, >9
      |  mov TMPR, FOR_STOP
      if (!vk) {
        |  checkint TMPR, ->vmeta_for
        |  mov ITYPE, FOR_STEP
        |  test ITYPEd, ITYPEd; js >5
        |  sar ITYPE, 47;
        |  cmp ITYPEd, LJ_TISNUM; jne ->vmeta_for
      } else {
#ifdef LUA_USE_ASSERT
        |  checkinttp FOR_STOP, ->assert_bad_for_arg_type
        |  checkinttp FOR_STEP, ->assert_bad_for_arg_type
#endif
        |  mov ITYPE, FOR_STEP
        |  test ITYPEd, ITYPEd; js >5
        |  add RBd, ITYPEd; jo >1
        |  setint RB
        |  mov FOR_IDX, RB
      }
      |  cmp RBd, TMPRd
      |  mov FOR_EXT, RB
      if (op == BC_FORI) {
        |  jle >7
        |1:
        |6:
        |  branchPC RD
      } else if (op == BC_JFORI) {
        |  branchPC RD
        |  movzx RDd, PC_RD
        |  jle =>BC_JLOOP
        |1:
        |6:
      } else if (op == BC_IFORL) {
        |  jg >7
        |6:
        |  branchPC RD
        |1:
      } else {
        |  jle =>BC_JLOOP
        |1:
        |6:
      }
      |7:
      |  ins_next
      |
      |5:  // Invert check for negative step.
      if (!vk) {
        |  sar ITYPE, 47;
        |  cmp ITYPEd, LJ_TISNUM; jne ->vmeta_for
      } else {
        |  add RBd, ITYPEd; jo <1
        |  setint RB
        |  mov FOR_IDX, RB
      }
      |  cmp RBd, TMPRd
      |  mov FOR_EXT, RB
      if (op == BC_FORI) {
        |  jge <7
      } else if (op == BC_JFORI) {
        |  branchPC RD
        |  movzx RDd, PC_RD
        |  jge =>BC_JLOOP
      } else if (op == BC_IFORL) {
        |  jl <7
      } else {
        |  jge =>BC_JLOOP
      }
      |  jmp <6
      |9:  // Fallback to FP variant.
      if (!vk) {
        |  jae ->vmeta_for
      }
    } else if (!vk) {
      |  checknumtp FOR_IDX, ->vmeta_for
    }
    if (!vk) {
      |  checknumtp FOR_STOP, ->vmeta_for
    } else {
#ifdef LUA_USE_ASSERT
      |  checknumtp FOR_STOP, ->assert_bad_for_arg_type
      |  checknumtp FOR_STEP, ->assert_bad_for_arg_type
#endif
    }
    |  mov RB, FOR_STEP
    if (!vk) {
      |  checknum RB, ->vmeta_for
    }
    |  movsd xmm0, qword FOR_IDX
    |  movsd xmm1, qword FOR_STOP
    if (vk) {
      |  addsd xmm0, qword FOR_STEP
      |  movsd qword FOR_IDX, xmm0
      |  test RB, RB; js >3
    } else {
      |  jl >3
    }
    |  ucomisd xmm1, xmm0
    |1:
    |  movsd qword FOR_EXT, xmm0
    if (op == BC_FORI) {
      |.if DUALNUM
      |  jnb <7
      |.else
      |  jnb >2
      |  branchPC RD
      |.endif
    } else if (op == BC_JFORI) {
      |  branchPC RD
      |  movzx RDd, PC_RD
      |  jnb =>BC_JLOOP
    } else if (op == BC_IFORL) {
      |.if DUALNUM
      |  jb <7
      |.else
      |  jb >2
      |  branchPC RD
      |.endif
    } else {
      |  jnb =>BC_JLOOP
    }
    |.if DUALNUM
    |  jmp <6
    |.else
    |2:
    |  ins_next
    |.endif
    |
    |3:  // Invert comparison if step is negative.
    |  ucomisd xmm0, xmm1
    |  jmp <1
    break;

  case BC_ITERL:
    |.if JIT
    |  hotloop RBd
    |.endif
    | // Fall through. Assumes BC_IITERL follows and ins_AJ is a no-op.
    break;

  case BC_JITERL:
#if !LJ_HASJIT
    break;
#endif
  case BC_IITERL:
    |  ins_AJ   // RA = base, RD = target
    |  lea RA, [BASE+RA*8]
    |  mov RB, [RA]
    |  cmp RB, LJ_TNIL; je >1           // Stop if iterator returned nil.
    if (op == BC_JITERL) {
      |  mov [RA-8], RB
      |  jmp =>BC_JLOOP
    } else {
      |  branchPC RD                    // Otherwise save control var + branch.
      |  mov [RA-8], RB
    }
    |1:
    |  ins_next
    break;

  case BC_LOOP:
    |  ins_A    // RA = base, RD = target (loop extent)
    |  // Note: RA/RD is only used by trace recorder to determine scope/extent
    |  // This opcode does NOT jump, it's only purpose is to detect a hot loop.
    |.if JIT
    |  hotloop RBd
    |.endif
    | // Fall through. Assumes BC_ILOOP follows and ins_A is a no-op.
    break;

  case BC_ILOOP:
    |  ins_A    // RA = base, RD = target (loop extent)
    |  ins_next
    break;

  case BC_JLOOP:
    |.if JIT
    |  ins_AD   // RA = base (ignored), RD = traceno
    |  mov RA, [DISPATCH+DISPATCH_J(trace)]
    |  mov TRACE:RD, [RA+RD*8]
    |  mov RD, TRACE:RD->mcode
    |  mov L:RB, SAVE_L
    |  mov [DISPATCH+DISPATCH_GL(jit_base)], BASE
    |  mov [DISPATCH+DISPATCH_GL(tmpbuf.L)], L:RB
    |  // Save additional callee-save registers only used in compiled code.
    |.if X64WIN
    |  mov CSAVE_4, r12
    |  mov CSAVE_3, r13
    |  mov CSAVE_2, r14
    |  mov CSAVE_1, r15
    |  mov RA, rsp
    |  sub rsp, 10*16+4*8
    |  movdqa [RA-1*16], xmm6
    |  movdqa [RA-2*16], xmm7
    |  movdqa [RA-3*16], xmm8
    |  movdqa [RA-4*16], xmm9
    |  movdqa [RA-5*16], xmm10
    |  movdqa [RA-6*16], xmm11
    |  movdqa [RA-7*16], xmm12
    |  movdqa [RA-8*16], xmm13
    |  movdqa [RA-9*16], xmm14
    |  movdqa [RA-10*16], xmm15
    |.else
    |  sub rsp, 16
    |  mov [rsp+16], r12
    |  mov [rsp+8], r13
    |.endif
    |  jmp RD
    |.endif
    break;

  case BC_JMP:
    |  ins_AJ   // RA = unused, RD = target
    |  branchPC RD
    |  ins_next
    break;

  /* -- Function headers -------------------------------------------------- */

   /*
   ** Reminder: A function may be called with func/args above L->maxstack,
   ** i.e. occupying EXTRA_STACK slots. And vmeta_call may add one extra slot,
   ** too. This means all FUNC* ops (including fast functions) must check
   ** for stack overflow _before_ adding more slots!
   */

  case BC_FUNCF:
    |.if JIT
    |  hotcall RBd
    |.endif
  case BC_FUNCV:  /* NYI: compiled vararg functions. */
    | // Fall through. Assumes BC_IFUNCF/BC_IFUNCV follow and ins_AD is a no-op.
    break;

  case BC_JFUNCF:
#if !LJ_HASJIT
    break;
#endif
  case BC_IFUNCF:
    |  ins_AD  // BASE = new base, RA = framesize, RD = nargs+1
    |  mov KBASE, [PC-4+PC2PROTO(k)]
    |  mov L:RB, SAVE_L
    |  lea RA, [BASE+RA*8]              // Top of frame.
    |  cmp RA, L:RB->maxstack
    |  ja ->vm_growstack_f
    |  movzx RAd, byte [PC-4+PC2PROTO(numparams)]
    |  cmp NARGS:RDd, RAd               // Check for missing parameters.
    |  jbe >3
    |2:
    if (op == BC_JFUNCF) {
      |  movzx RDd, PC_RD
      |  jmp =>BC_JLOOP
    } else {
      |  ins_next
    }
    |
    |3:  // Clear missing parameters.
    |  mov aword [BASE+NARGS:RD*8-8], LJ_TNIL
    |  add NARGS:RDd, 1
    |  cmp NARGS:RDd, RAd
    |  jbe <3
    |  jmp <2
    break;

  case BC_JFUNCV:
#if !LJ_HASJIT
    break;
#endif
    | int3  // NYI: compiled vararg functions
    break;  /* NYI: compiled vararg functions. */

  case BC_IFUNCV:
    |  ins_AD  // BASE = new base, RA = framesize, RD = nargs+1
    |  lea RBd, [NARGS:RD*8+FRAME_VARG+8]
    |  lea RD, [BASE+NARGS:RD*8+8]
    |  mov LFUNC:KBASE, [BASE-16]
    |  mov [RD-8], RB                   // Store delta + FRAME_VARG.
    |  mov [RD-16], LFUNC:KBASE         // Store copy of LFUNC.
    |  mov L:RB, SAVE_L
    |  lea RA, [RD+RA*8]
    |  cmp RA, L:RB->maxstack
    |  ja ->vm_growstack_v              // Need to grow stack.
    |  mov RA, BASE
    |  mov BASE, RD
    |  movzx RBd, byte [PC-4+PC2PROTO(numparams)]
    |  test RBd, RBd
    |  jz >2
    |  add RA, 8
    |1:  // Copy fixarg slots up to new frame.
    |  add RA, 8
    |  cmp RA, BASE
    |  jnb >3                           // Less args than parameters?
    |  mov KBASE, [RA-16]
    |  mov [RD], KBASE
    |  add RD, 8
    |  mov aword [RA-16], LJ_TNIL       // Clear old fixarg slot (help the GC).
    |  sub RBd, 1
    |  jnz <1
    |2:
    if (op == BC_JFUNCV) {
      |  movzx RDd, PC_RD
      |  jmp =>BC_JLOOP
    } else {
      |  mov KBASE, [PC-4+PC2PROTO(k)]
      |  ins_next
    }
    |
    |3:  // Clear missing parameters.
    |  mov aword [RD], LJ_TNIL
    |  add RD, 8
    |  sub RBd, 1
    |  jnz <3
    |  jmp <2
    break;

  case BC_FUNCC:
  case BC_FUNCCW:
    |  ins_AD  // BASE = new base, RA = ins RA|RD (unused), RD = nargs+1
    |  mov CFUNC:RB, [BASE-16]
    |  cleartp CFUNC:RB
    |  mov KBASE, CFUNC:RB->f
    |  mov L:RB, SAVE_L
    |  lea RD, [BASE+NARGS:RD*8-8]
    |  mov L:RB->base, BASE
    |  lea RA, [RD+8*LUA_MINSTACK]
    |  cmp RA, L:RB->maxstack
    |  mov L:RB->top, RD
    if (op == BC_FUNCC) {
      |  mov CARG1, L:RB                // Caveat: CARG1 may be RA.
    } else {
      |  mov CARG2, KBASE
      |  mov CARG1, L:RB                // Caveat: CARG1 may be RA.
    }
    |  ja ->vm_growstack_c              // Need to grow stack.
    |  set_vmstate C
    if (op == BC_FUNCC) {
      |  call KBASE                     // (lua_State *L)
    } else {
      |  // (lua_State *L, lua_CFunction f)
      |  call aword [DISPATCH+DISPATCH_GL(wrapf)]
    }
    |  // nresults returned in eax (RD).
    |  mov BASE, L:RB->base
    |  mov [DISPATCH+DISPATCH_GL(cur_L)], L:RB
    |  set_vmstate INTERP
    |  lea RA, [BASE+RD*8]
    |  neg RA
    |  add RA, L:RB->top                // RA = (L->top-(L->base+nresults))*8
    |  mov PC, [BASE-8]                 // Fetch PC of caller.
    |  jmp ->vm_returnc
    break;

  /* ---------------------------------------------------------------------- */

  default:
    fprintf(stderr, "Error: undefined opcode BC_%s\n", bc_names[op]);
    exit(2);
    break;
  }
}

static int build_backend(BuildCtx *ctx)
{
  int op;
  dasm_growpc(Dst, BC__MAX);
  build_subroutines(ctx);
  |.code_op
  for (op = 0; op < BC__MAX; op++)
    build_ins(ctx, (BCOp)op, op);
  return BC__MAX;
}

/* Emit pseudo frame-info for all assembler functions. */
static void emit_asm_debug(BuildCtx *ctx)
{
  int fcofs = (int)((uint8_t *)ctx->glob[GLOB_vm_ffi_call] - ctx->code);
  switch (ctx->mode) {
  case BUILD_elfasm:
    fprintf(ctx->fp, "\t.section .debug_frame,\"\",@progbits\n");
    fprintf(ctx->fp,
        ".Lframe0:\n"
        "\t.long .LECIE0-.LSCIE0\n"
        ".LSCIE0:\n"
        "\t.long 0xffffffff\n"
        "\t.byte 0x1\n"
        "\t.string \"\"\n"
        "\t.uleb128 0x1\n"
        "\t.sleb128 -8\n"
        "\t.byte 0x10\n"
        "\t.byte 0xc\n\t.uleb128 0x7\n\t.uleb128 8\n"
        "\t.byte 0x80+0x10\n\t.uleb128 0x1\n"
        "\t.align 8\n"
        ".LECIE0:\n\n");
    fprintf(ctx->fp,
        ".LSFDE0:\n"
        "\t.long .LEFDE0-.LASFDE0\n"
        ".LASFDE0:\n"
        "\t.long .Lframe0\n"
        "\t.quad .Lbegin\n"
        "\t.quad %d\n"
        "\t.byte 0xe\n\t.uleb128 %d\n"          /* def_cfa_offset */
        "\t.byte 0x86\n\t.uleb128 0x2\n"        /* offset rbp */
        "\t.byte 0x83\n\t.uleb128 0x3\n"        /* offset rbx */
        "\t.byte 0x8f\n\t.uleb128 0x4\n"        /* offset r15 */
        "\t.byte 0x8e\n\t.uleb128 0x5\n"        /* offset r14 */
#if LJ_NO_UNWIND
        "\t.byte 0x8d\n\t.uleb128 0x6\n"        /* offset r13 */
        "\t.byte 0x8c\n\t.uleb128 0x7\n"        /* offset r12 */
#endif
        "\t.align 8\n"
        ".LEFDE0:\n\n", fcofs, CFRAME_SIZE);
#if LJ_HASFFI
    fprintf(ctx->fp,
        ".LSFDE1:\n"
        "\t.long .LEFDE1-.LASFDE1\n"
        ".LASFDE1:\n"
        "\t.long .Lframe0\n"
        "\t.quad lj_vm_ffi_call\n"
        "\t.quad %d\n"
        "\t.byte 0xe\n\t.uleb128 16\n"          /* def_cfa_offset */
        "\t.byte 0x86\n\t.uleb128 0x2\n"        /* offset rbp */
        "\t.byte 0xd\n\t.uleb128 0x6\n"         /* def_cfa_register rbp */
        "\t.byte 0x83\n\t.uleb128 0x3\n"        /* offset rbx */
        "\t.align 8\n"
        ".LEFDE1:\n\n", (int)ctx->codesz - fcofs);
#endif
#if !LJ_NO_UNWIND
#if (defined(__sun__) && defined(__svr4__))
    fprintf(ctx->fp, "\t.section .eh_frame,\"a\",@unwind\n");
#else
    fprintf(ctx->fp, "\t.section .eh_frame,\"a\",@progbits\n");
#endif
    fprintf(ctx->fp,
        ".Lframe1:\n"
        "\t.long .LECIE1-.LSCIE1\n"
        ".LSCIE1:\n"
        "\t.long 0\n"
        "\t.byte 0x1\n"
        "\t.string \"zPR\"\n"
        "\t.uleb128 0x1\n"
        "\t.sleb128 -8\n"
        "\t.byte 0x10\n"
        "\t.uleb128 6\n"                        /* augmentation length */
        "\t.byte 0x1b\n"                        /* pcrel|sdata4 */
        "\t.long lj_err_unwind_dwarf-.\n"
        "\t.byte 0x1b\n"                        /* pcrel|sdata4 */
        "\t.byte 0xc\n\t.uleb128 0x7\n\t.uleb128 8\n"
        "\t.byte 0x80+0x10\n\t.uleb128 0x1\n"
        "\t.align 8\n"
        ".LECIE1:\n\n");
    fprintf(ctx->fp,
        ".LSFDE2:\n"
        "\t.long .LEFDE2-.LASFDE2\n"
        ".LASFDE2:\n"
        "\t.long .LASFDE2-.Lframe1\n"
        "\t.long .Lbegin-.\n"
        "\t.long %d\n"
        "\t.uleb128 0\n"                        /* augmentation length */
        "\t.byte 0xe\n\t.uleb128 %d\n"          /* def_cfa_offset */
        "\t.byte 0x86\n\t.uleb128 0x2\n"        /* offset rbp */
        "\t.byte 0x83\n\t.uleb128 0x3\n"        /* offset rbx */
        "\t.byte 0x8f\n\t.uleb128 0x4\n"        /* offset r15 */
        "\t.byte 0x8e\n\t.uleb128 0x5\n"        /* offset r14 */
        "\t.align 8\n"
        ".LEFDE2:\n\n", fcofs, CFRAME_SIZE);
#if LJ_HASFFI
    fprintf(ctx->fp,
        ".Lframe2:\n"
        "\t.long .LECIE2-.LSCIE2\n"
        ".LSCIE2:\n"
        "\t.long 0\n"
        "\t.byte 0x1\n"
        "\t.string \"zR\"\n"
        "\t.uleb128 0x1\n"
        "\t.sleb128 -8\n"
        "\t.byte 0x10\n"
        "\t.uleb128 1\n"                        /* augmentation length */
        "\t.byte 0x1b\n"                        /* pcrel|sdata4 */
        "\t.byte 0xc\n\t.uleb128 0x7\n\t.uleb128 8\n"
        "\t.byte 0x80+0x10\n\t.uleb128 0x1\n"
        "\t.align 8\n"
        ".LECIE2:\n\n");
    fprintf(ctx->fp,
        ".LSFDE3:\n"
        "\t.long .LEFDE3-.LASFDE3\n"
        ".LASFDE3:\n"
        "\t.long .LASFDE3-.Lframe2\n"
        "\t.long lj_vm_ffi_call-.\n"
        "\t.long %d\n"
        "\t.uleb128 0\n"                        /* augmentation length */
        "\t.byte 0xe\n\t.uleb128 16\n"          /* def_cfa_offset */
        "\t.byte 0x86\n\t.uleb128 0x2\n"        /* offset rbp */
        "\t.byte 0xd\n\t.uleb128 0x6\n"         /* def_cfa_register rbp */
        "\t.byte 0x83\n\t.uleb128 0x3\n"        /* offset rbx */
        "\t.align 8\n"
        ".LEFDE3:\n\n", (int)ctx->codesz - fcofs);
#endif
#endif
    break;
#if !LJ_NO_UNWIND
  /* Mental note: never let Apple design an assembler.
  ** Or a linker. Or a plastic case. But I digress.
  */
  case BUILD_machasm: {
#if LJ_HASFFI
    int fcsize = 0;
#endif
    int i;
    fprintf(ctx->fp, "\t.section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support\n");
    fprintf(ctx->fp,
        "EH_frame1:\n"
        "\t.set L$set$x,LECIEX-LSCIEX\n"
        "\t.long L$set$x\n"
        "LSCIEX:\n"
        "\t.long 0\n"
        "\t.byte 0x1\n"
        "\t.ascii \"zPR\\0\"\n"
        "\t.byte 0x1\n"
        "\t.byte 128-8\n"
        "\t.byte 0x10\n"
        "\t.byte 6\n"                           /* augmentation length */
        "\t.byte 0x9b\n"                        /* indirect|pcrel|sdata4 */
        "\t.long _lj_err_unwind_dwarf+4@GOTPCREL\n"
        "\t.byte 0x1b\n"                        /* pcrel|sdata4 */
        "\t.byte 0xc\n\t.byte 0x7\n\t.byte 8\n"
        "\t.byte 0x80+0x10\n\t.byte 0x1\n"
        "\t.align 3\n"
        "LECIEX:\n\n");
    for (i = 0; i < ctx->nsym; i++) {
      const char *name = ctx->sym[i].name;
      int32_t size = ctx->sym[i+1].ofs - ctx->sym[i].ofs;
      if (size == 0) continue;
#if LJ_HASFFI
      if (!strcmp(name, "_lj_vm_ffi_call")) { fcsize = size; continue; }
#endif
      fprintf(ctx->fp,
          "%s.eh:\n"
          "LSFDE%d:\n"
          "\t.set L$set$%d,LEFDE%d-LASFDE%d\n"
          "\t.long L$set$%d\n"
          "LASFDE%d:\n"
          "\t.long LASFDE%d-EH_frame1\n"
          "\t.long %s-.\n"
          "\t.long %d\n"
          "\t.byte 0\n"                         /* augmentation length */
          "\t.byte 0xe\n\t.byte %d\n"           /* def_cfa_offset */
          "\t.byte 0x86\n\t.byte 0x2\n"         /* offset rbp */
          "\t.byte 0x83\n\t.byte 0x3\n"         /* offset rbx */
          "\t.byte 0x8f\n\t.byte 0x4\n"         /* offset r15 */
          "\t.byte 0x8e\n\t.byte 0x5\n"         /* offset r14 */
          "\t.align 3\n"
          "LEFDE%d:\n\n",
          name, i, i, i, i, i, i, i, name, size, CFRAME_SIZE, i);
    }
#if LJ_HASFFI
    if (fcsize) {
      fprintf(ctx->fp,
          "EH_frame2:\n"
          "\t.set L$set$y,LECIEY-LSCIEY\n"
          "\t.long L$set$y\n"
          "LSCIEY:\n"
          "\t.long 0\n"
          "\t.byte 0x1\n"
          "\t.ascii \"zR\\0\"\n"
          "\t.byte 0x1\n"
          "\t.byte 128-8\n"
          "\t.byte 0x10\n"
          "\t.byte 1\n"                         /* augmentation length */
          "\t.byte 0x1b\n"                      /* pcrel|sdata4 */
          "\t.byte 0xc\n\t.byte 0x7\n\t.byte 8\n"
          "\t.byte 0x80+0x10\n\t.byte 0x1\n"
          "\t.align 3\n"
          "LECIEY:\n\n");
      fprintf(ctx->fp,
          "_lj_vm_ffi_call.eh:\n"
          "LSFDEY:\n"
          "\t.set L$set$yy,LEFDEY-LASFDEY\n"
          "\t.long L$set$yy\n"
          "LASFDEY:\n"
          "\t.long LASFDEY-EH_frame2\n"
          "\t.long _lj_vm_ffi_call-.\n"
          "\t.long %d\n"
          "\t.byte 0\n"                         /* augmentation length */
          "\t.byte 0xe\n\t.byte 16\n"           /* def_cfa_offset */
          "\t.byte 0x86\n\t.byte 0x2\n"         /* offset rbp */
          "\t.byte 0xd\n\t.byte 0x6\n"          /* def_cfa_register rbp */
          "\t.byte 0x83\n\t.byte 0x3\n"         /* offset rbx */
          "\t.align 3\n"
          "LEFDEY:\n\n", fcsize);
    }
#endif
    fprintf(ctx->fp, ".subsections_via_symbols\n");
    }
    break;
#endif
  default:  /* Difficult for other modes. */
    break;
  }
}