boehm-gc/mach_dep.c

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
   4  *
   5  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   6  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   7  *
   8  * Permission is hereby granted to use or copy this program
   9  * for any purpose,  provided the above notices are retained on all copies.
  10  * Permission to modify the code and to distribute modified code is granted,
  11  * provided the above notices are retained, and a notice that the code was
  12  * modified is included with the above copyright notice.
  13  */
  14 /* Boehm, November 17, 1995 12:13 pm PST */
  15 # include "gc_priv.h"
  16 # include <stdio.h>
  17 # include <setjmp.h>
  18 # if defined(OS2) || defined(CX_UX)
  19 #   define _setjmp(b) setjmp(b)
  20 #   define _longjmp(b,v) longjmp(b,v)
  21 # endif
  22 # ifdef AMIGA
  23 #   ifndef __GNUC__
  24 #     include <dos/dos.h>
  25 #   else
  26 #     include <machine/reg.h>
  27 #   endif
  28 # endif
  29
  30 #if defined(__MWERKS__) && !defined(POWERPC)
  31
  32 asm static void PushMacRegisters()
  33 {
  34     sub.w   #4,sp                   // reserve space for one parameter.
  35     move.l  a2,(sp)
  36     jsr         GC_push_one
  37     move.l  a3,(sp)
  38     jsr         GC_push_one
  39     move.l  a4,(sp)
  40     jsr         GC_push_one
  41 #   if !__option(a6frames)
  42         // <pcb> perhaps a6 should be pushed if stack frames are not being used.
  43         move.l  a6,(sp)
  44         jsr             GC_push_one
  45 #   endif
  46         // skip a5 (globals), a6 (frame pointer), and a7 (stack pointer)
  47     move.l  d2,(sp)
  48     jsr         GC_push_one
  49     move.l  d3,(sp)
  50     jsr         GC_push_one
  51     move.l  d4,(sp)
  52     jsr         GC_push_one
  53     move.l  d5,(sp)
  54     jsr         GC_push_one
  55     move.l  d6,(sp)
  56     jsr         GC_push_one
  57     move.l  d7,(sp)
  58     jsr         GC_push_one
  59     add.w   #4,sp                   // fix stack.
  60     rts
  61 }
  62
  63 #endif /* __MWERKS__ */
  64
  65 # if defined(SPARC) || defined(IA64)
  66     /* Value returned from register flushing routine; either sp (SPARC) */
  67     /* or ar.bsp (IA64)                                                 */
  68     word GC_save_regs_ret_val;
  69 # endif
  70
  71 /* Routine to mark from registers that are preserved by the C compiler. */
  72 /* This must be ported to every new architecture.  There is a generic   */
  73 /* version at the end, that is likely, but not guaranteed to work       */
  74 /* on your architecture.  Run the test_setjmp program to see whether    */
  75 /* there is any chance it will work.                                    */
  76
  77 #ifndef USE_GENERIC_PUSH_REGS
  78 void GC_push_regs()
  79 {
  80 #       ifdef RT
  81           register long TMP_SP; /* must be bound to r11 */
  82 #       endif
  83
  84 #       if defined(MIPS) && defined(LINUX)
  85           /* I'm not sure whether this has actually been tested. */
  86 #         define call_push(x)     asm("move $4," x ";"); asm("jal GC_push_one")
  87           call_push("$2");
  88           call_push("$3");
  89           call_push("$16");
  90           call_push("$17");
  91           call_push("$18");
  92           call_push("$19");
  93           call_push("$20");
  94           call_push("$21");
  95           call_push("$22");
  96           call_push("$23");
  97           call_push("$30");
  98 #         undef call_push
  99 #       endif   /* MIPS && LINUX */
 100
 101 #       ifdef VAX
 102           /* VAX - generic code below does not work under 4.2 */
 103           /* r1 through r5 are caller save, and therefore     */
 104           /* on the stack or dead.                            */
 105           asm("pushl r11");     asm("calls $1,_GC_push_one");
 106           asm("pushl r10");     asm("calls $1,_GC_push_one");
 107           asm("pushl r9");      asm("calls $1,_GC_push_one");
 108           asm("pushl r8");      asm("calls $1,_GC_push_one");
 109           asm("pushl r7");      asm("calls $1,_GC_push_one");
 110           asm("pushl r6");      asm("calls $1,_GC_push_one");
 111 #       endif
 112 #       if defined(M68K) && (defined(SUNOS4) || defined(NEXT))
 113         /*  M68K SUNOS - could be replaced by generic code */
 114           /* a0, a1 and d1 are caller save          */
 115           /*  and therefore are on stack or dead.   */
 116
 117           asm("subqw #0x4,sp");         /* allocate word on top of stack */
 118
 119           asm("movl a2,sp@");   asm("jbsr _GC_push_one");
 120           asm("movl a3,sp@");   asm("jbsr _GC_push_one");
 121           asm("movl a4,sp@");   asm("jbsr _GC_push_one");
 122           asm("movl a5,sp@");   asm("jbsr _GC_push_one");
 123           /* Skip frame pointer and stack pointer */
 124           asm("movl d1,sp@");   asm("jbsr _GC_push_one");
 125           asm("movl d2,sp@");   asm("jbsr _GC_push_one");
 126           asm("movl d3,sp@");   asm("jbsr _GC_push_one");
 127           asm("movl d4,sp@");   asm("jbsr _GC_push_one");
 128           asm("movl d5,sp@");   asm("jbsr _GC_push_one");
 129           asm("movl d6,sp@");   asm("jbsr _GC_push_one");
 130           asm("movl d7,sp@");   asm("jbsr _GC_push_one");
 131
 132           asm("addqw #0x4,sp");         /* put stack back where it was  */
 133 #       endif
 134
 135 #       if defined(M68K) && defined(HP)
 136         /*  M68K HP - could be replaced by generic code */
 137           /* a0, a1 and d1 are caller save.  */
 138
 139           asm("subq.w &0x4,%sp");       /* allocate word on top of stack */
 140
 141           asm("mov.l %a2,(%sp)"); asm("jsr _GC_push_one");
 142           asm("mov.l %a3,(%sp)"); asm("jsr _GC_push_one");
 143           asm("mov.l %a4,(%sp)"); asm("jsr _GC_push_one");
 144           asm("mov.l %a5,(%sp)"); asm("jsr _GC_push_one");
 145           /* Skip frame pointer and stack pointer */
 146           asm("mov.l %d1,(%sp)"); asm("jsr _GC_push_one");
 147           asm("mov.l %d2,(%sp)"); asm("jsr _GC_push_one");
 148           asm("mov.l %d3,(%sp)"); asm("jsr _GC_push_one");
 149           asm("mov.l %d4,(%sp)"); asm("jsr _GC_push_one");
 150           asm("mov.l %d5,(%sp)"); asm("jsr _GC_push_one");
 151           asm("mov.l %d6,(%sp)"); asm("jsr _GC_push_one");
 152           asm("mov.l %d7,(%sp)"); asm("jsr _GC_push_one");
 153
 154           asm("addq.w &0x4,%sp");       /* put stack back where it was  */
 155 #       endif /* M68K HP */
 156
 157 #       if defined(M68K) && defined(AMIGA)
 158          /*  AMIGA - could be replaced by generic code                  */
 159          /* a0, a1, d0 and d1 are caller save */
 160
 161 #        ifdef __GNUC__
 162           asm("subq.w &0x4,%sp");       /* allocate word on top of stack */
 163
 164           asm("mov.l %a2,(%sp)"); asm("jsr _GC_push_one");
 165           asm("mov.l %a3,(%sp)"); asm("jsr _GC_push_one");
 166           asm("mov.l %a4,(%sp)"); asm("jsr _GC_push_one");
 167           asm("mov.l %a5,(%sp)"); asm("jsr _GC_push_one");
 168           asm("mov.l %a6,(%sp)"); asm("jsr _GC_push_one");
 169           /* Skip frame pointer and stack pointer */
 170           asm("mov.l %d2,(%sp)"); asm("jsr _GC_push_one");
 171           asm("mov.l %d3,(%sp)"); asm("jsr _GC_push_one");
 172           asm("mov.l %d4,(%sp)"); asm("jsr _GC_push_one");
 173           asm("mov.l %d5,(%sp)"); asm("jsr _GC_push_one");
 174           asm("mov.l %d6,(%sp)"); asm("jsr _GC_push_one");
 175           asm("mov.l %d7,(%sp)"); asm("jsr _GC_push_one");
 176
 177           asm("addq.w &0x4,%sp");       /* put stack back where it was  */
 178 #        else /* !__GNUC__ */
 179           GC_push_one(getreg(REG_A2));
 180           GC_push_one(getreg(REG_A3));
 181           GC_push_one(getreg(REG_A4));
 182           GC_push_one(getreg(REG_A5));
 183           GC_push_one(getreg(REG_A6));
 184           /* Skip stack pointer */
 185           GC_push_one(getreg(REG_D2));
 186           GC_push_one(getreg(REG_D3));
 187           GC_push_one(getreg(REG_D4));
 188           GC_push_one(getreg(REG_D5));
 189           GC_push_one(getreg(REG_D6));
 190           GC_push_one(getreg(REG_D7));
 191 #        endif /* !__GNUC__ */
 192 #       endif /* AMIGA */
 193
 194 #       if defined(M68K) && defined(MACOS)
 195 #       if defined(THINK_C)
 196 #         define PushMacReg(reg) \
 197               move.l  reg,(sp) \
 198               jsr             GC_push_one
 199           asm {
 200               sub.w   #4,sp                   ; reserve space for one parameter.
 201               PushMacReg(a2);
 202               PushMacReg(a3);
 203               PushMacReg(a4);
 204               ; skip a5 (globals), a6 (frame pointer), and a7 (stack pointer)
 205               PushMacReg(d2);
 206               PushMacReg(d3);
 207               PushMacReg(d4);
 208               PushMacReg(d5);
 209               PushMacReg(d6);
 210               PushMacReg(d7);
 211               add.w   #4,sp                   ; fix stack.
 212           }
 213 #         undef PushMacReg
 214 #       endif /* THINK_C */
 215 #       if defined(__MWERKS__)
 216           PushMacRegisters();
 217 #       endif   /* __MWERKS__ */
 218 #   endif       /* MACOS */
 219
 220 #       if defined(I386) &&!defined(OS2) &&!defined(SVR4) \
 221         && (defined(__MINGW32__) || !defined(MSWIN32)) \
 222         && !defined(SCO) && !defined(SCO_ELF) \
 223         && !(defined(LINUX)       && defined(__ELF__)) \
 224         && !(defined(FREEBSD) && defined(__ELF__)) \
 225         && !defined(DOS4GW)
 226         /* I386 code, generic code does not appear to work */
 227         /* It does appear to work under OS2, and asms dont */
 228         /* This is used for some 38g UNIX variants and for CYGWIN32 */
 229           asm("pushl %eax");  asm("call _GC_push_one"); asm("addl $4,%esp");
 230           asm("pushl %ecx");  asm("call _GC_push_one"); asm("addl $4,%esp");
 231           asm("pushl %edx");  asm("call _GC_push_one"); asm("addl $4,%esp");
 232           asm("pushl %ebp");  asm("call _GC_push_one"); asm("addl $4,%esp");
 233           asm("pushl %esi");  asm("call _GC_push_one"); asm("addl $4,%esp");
 234           asm("pushl %edi");  asm("call _GC_push_one"); asm("addl $4,%esp");
 235           asm("pushl %ebx");  asm("call _GC_push_one"); asm("addl $4,%esp");
 236 #       endif
 237
 238 #       if ( defined(I386) && defined(LINUX) && defined(__ELF__) ) \
 239         || ( defined(I386) && defined(FREEBSD) && defined(__ELF__) )
 240
 241         /* This is modified for Linux with ELF (Note: _ELF_ only) */
 242         /* This section handles FreeBSD with ELF. */
 243         /* Eax is caller-save and dead here.  Other caller-save         */
 244         /* registers could also be skipped.  We assume there are no     */
 245         /* pointers in MMX registers, etc.                              */
 246         /* We combine instructions in a single asm to prevent gcc from  */
 247         /* inserting code in the middle.                                */
 248           asm("pushl %ecx; call GC_push_one; addl $4,%esp");
 249           asm("pushl %edx; call GC_push_one; addl $4,%esp");
 250           asm("pushl %ebp; call GC_push_one; addl $4,%esp");
 251           asm("pushl %esi; call GC_push_one; addl $4,%esp");
 252           asm("pushl %edi; call GC_push_one; addl $4,%esp");
 253           asm("pushl %ebx; call GC_push_one; addl $4,%esp");
 254 #       endif
 255
 256 #       if defined(I386) && defined(MSWIN32) && !defined(__MINGW32__) \
 257            && !defined(USE_GENERIC)
 258         /* I386 code, Microsoft variant         */
 259           __asm  push eax
 260           __asm  call GC_push_one
 261           __asm  add esp,4
 262           __asm  push ebx
 263           __asm  call GC_push_one
 264           __asm  add esp,4
 265           __asm  push ecx
 266           __asm  call GC_push_one
 267           __asm  add esp,4
 268           __asm  push edx
 269           __asm  call GC_push_one
 270           __asm  add esp,4
 271           __asm  push ebp
 272           __asm  call GC_push_one
 273           __asm  add esp,4
 274           __asm  push esi
 275           __asm  call GC_push_one
 276           __asm  add esp,4
 277           __asm  push edi
 278           __asm  call GC_push_one
 279           __asm  add esp,4
 280 #       endif
 281
 282 #       if defined(I386) && (defined(SVR4) || defined(SCO) || defined(SCO_ELF))
 283         /* I386 code, SVR4 variant, generic code does not appear to work */
 284           asm("pushl %eax");  asm("call GC_push_one"); asm("addl $4,%esp");
 285           asm("pushl %ebx");  asm("call GC_push_one"); asm("addl $4,%esp");
 286           asm("pushl %ecx");  asm("call GC_push_one"); asm("addl $4,%esp");
 287           asm("pushl %edx");  asm("call GC_push_one"); asm("addl $4,%esp");
 288           asm("pushl %ebp");  asm("call GC_push_one"); asm("addl $4,%esp");
 289           asm("pushl %esi");  asm("call GC_push_one"); asm("addl $4,%esp");
 290           asm("pushl %edi");  asm("call GC_push_one"); asm("addl $4,%esp");
 291 #       endif
 292
 293 #       ifdef NS32K
 294           asm ("movd r3, tos"); asm ("bsr ?_GC_push_one"); asm ("adjspb $-4");
 295           asm ("movd r4, tos"); asm ("bsr ?_GC_push_one"); asm ("adjspb $-4");
 296           asm ("movd r5, tos"); asm ("bsr ?_GC_push_one"); asm ("adjspb $-4");
 297           asm ("movd r6, tos"); asm ("bsr ?_GC_push_one"); asm ("adjspb $-4");
 298           asm ("movd r7, tos"); asm ("bsr ?_GC_push_one"); asm ("adjspb $-4");
 299 #       endif
 300
 301 #       if defined(SPARC)
 302           {
 303               word GC_save_regs_in_stack();
 304
 305               GC_save_regs_ret_val = GC_save_regs_in_stack();
 306           }
 307 #       endif
 308
 309 #       ifdef RT
 310             GC_push_one(TMP_SP);    /* GC_push_one from r11 */
 311
 312             asm("cas r11, r6, r0"); GC_push_one(TMP_SP);        /* r6 */
 313             asm("cas r11, r7, r0"); GC_push_one(TMP_SP);        /* through */
 314             asm("cas r11, r8, r0"); GC_push_one(TMP_SP);        /* r10 */
 315             asm("cas r11, r9, r0"); GC_push_one(TMP_SP);
 316             asm("cas r11, r10, r0"); GC_push_one(TMP_SP);
 317
 318             asm("cas r11, r12, r0"); GC_push_one(TMP_SP); /* r12 */
 319             asm("cas r11, r13, r0"); GC_push_one(TMP_SP); /* through */
 320             asm("cas r11, r14, r0"); GC_push_one(TMP_SP); /* r15 */
 321             asm("cas r11, r15, r0"); GC_push_one(TMP_SP);
 322 #       endif
 323
 324 #       if defined(M68K) && defined(SYSV)
 325         /*  Once again similar to SUN and HP, though setjmp appears to work.
 326                 --Parag
 327          */
 328 #        ifdef __GNUC__
 329           asm("subqw #0x4,%sp");        /* allocate word on top of stack */
 330
 331           asm("movl %a2,%sp@"); asm("jbsr GC_push_one");
 332           asm("movl %a3,%sp@"); asm("jbsr GC_push_one");
 333           asm("movl %a4,%sp@"); asm("jbsr GC_push_one");
 334           asm("movl %a5,%sp@"); asm("jbsr GC_push_one");
 335           /* Skip frame pointer and stack pointer */
 336           asm("movl %d1,%sp@"); asm("jbsr GC_push_one");
 337           asm("movl %d2,%sp@"); asm("jbsr GC_push_one");
 338           asm("movl %d3,%sp@"); asm("jbsr GC_push_one");
 339           asm("movl %d4,%sp@"); asm("jbsr GC_push_one");
 340           asm("movl %d5,%sp@"); asm("jbsr GC_push_one");
 341           asm("movl %d6,%sp@"); asm("jbsr GC_push_one");
 342           asm("movl %d7,%sp@"); asm("jbsr GC_push_one");
 343
 344           asm("addqw #0x4,%sp");        /* put stack back where it was  */
 345 #        else /* !__GNUC__*/
 346           asm("subq.w &0x4,%sp");       /* allocate word on top of stack */
 347
 348           asm("mov.l %a2,(%sp)"); asm("jsr GC_push_one");
 349           asm("mov.l %a3,(%sp)"); asm("jsr GC_push_one");
 350           asm("mov.l %a4,(%sp)"); asm("jsr GC_push_one");
 351           asm("mov.l %a5,(%sp)"); asm("jsr GC_push_one");
 352           /* Skip frame pointer and stack pointer */
 353           asm("mov.l %d1,(%sp)"); asm("jsr GC_push_one");
 354           asm("mov.l %d2,(%sp)"); asm("jsr GC_push_one");
 355           asm("mov.l %d3,(%sp)"); asm("jsr GC_push_one");
 356           asm("mov.l %d4,(%sp)"); asm("jsr GC_push_one");
 357           asm("mov.l %d5,(%sp)"); asm("jsr GC_push_one");
 358           asm("mov.l %d6,(%sp)"); asm("jsr GC_push_one");
 359           asm("mov.l %d7,(%sp)"); asm("jsr GC_push_one");
 360
 361           asm("addq.w &0x4,%sp");       /* put stack back where it was  */
 362 #        endif /* !__GNUC__ */
 363 #       endif /* M68K/SYSV */
 364
 365 #     if defined(PJ)
 366         {
 367             register int * sp asm ("optop");
 368             extern int *__libc_stack_end;
 369
 370             GC_push_all_stack (sp, __libc_stack_end);
 371         }
 372 #     endif
 373
 374       /* other machines... */
 375 #       if !(defined M68K) && !(defined VAX) && !(defined RT)
 376 #       if !(defined SPARC) && !(defined I386) && !(defined NS32K)
 377 #       if !defined(POWERPC) && !defined(UTS4)
 378 #       if !defined(PJ) && !(defined(MIPS) && defined(LINUX))
 379             --> bad news <--
 380 #       endif
 381 #       endif
 382 #       endif
 383 #       endif
 384 }
 385 #endif /* !USE_GENERIC_PUSH_REGS */
 386
 387 #if defined(USE_GENERIC_PUSH_REGS)
 388 void GC_generic_push_regs(cold_gc_frame)
 389 ptr_t cold_gc_frame;
 390 {
 391         /* Generic code                          */
 392         /* The idea is due to Parag Patel at HP. */
 393         /* We're not sure whether he would like  */
 394         /* to be he acknowledged for it or not.  */
 395         {
 396             static jmp_buf regs;
 397             register word * i = (word *) regs;
 398             register ptr_t lim = (ptr_t)(regs) + (sizeof regs);
 399
 400             /* Setjmp on Sun 3s doesn't clear all of the buffer.  */
 401             /* That tends to preserve garbage.  Clear it.         */
 402                 for (; (char *)i < lim; i++) {
 403                     *i = 0;
 404                 }
 405 #           if defined(POWERPC) || defined(MSWIN32) || defined(UTS4) || defined(LINUX)
 406                 (void) setjmp(regs);
 407 #           else
 408                 (void) _setjmp(regs);
 409 #           endif
 410 #           if defined(SPARC) || defined(IA64)
 411               /* On a register window machine, we need to save register */
 412               /* contents on the stack for this to work.  The setjmp    */
 413               /* is probably not needed on SPARC, since pointers are    */
 414               /* only stored in windowed or scratch registers.  It is   */
 415               /* needed on IA64, since some non-windowed registers are  */
 416               /* preserved.                                             */
 417               {
 418                 word GC_save_regs_in_stack();
 419
 420                 GC_save_regs_ret_val = GC_save_regs_in_stack();
 421               }
 422 #           endif
 423             GC_push_current_stack(cold_gc_frame);
 424         }
 425 }
 426 #endif /* USE_GENERIC_PUSH_REGS */
 427
 428 /* On register window machines, we need a way to force registers into   */
 429 /* the stack.   Return sp.                                              */
 430 # ifdef SPARC
 431     asm("       .seg    \"text\"");
 432 #   ifdef SVR4
 433       asm("     .globl  GC_save_regs_in_stack");
 434       asm("GC_save_regs_in_stack:");
 435       asm("     .type GC_save_regs_in_stack,#function");
 436 #   else
 437       asm("     .globl  _GC_save_regs_in_stack");
 438       asm("_GC_save_regs_in_stack:");
 439 #   endif
 440 #   if defined(__arch64__) || defined(__sparcv9)
 441     asm("       save    %sp,-128,%sp");
 442     asm("       flushw");
 443     asm("       ret");
 444     asm("       restore %sp,2047+128,%o0");
 445 #   else
 446     asm("       ta      0x3   ! ST_FLUSH_WINDOWS");
 447     asm("       retl");
 448     asm("       mov     %sp,%o0");
 449 #endif
 450 #   ifdef SVR4
 451       asm("     .GC_save_regs_in_stack_end:");
 452       asm("     .size GC_save_regs_in_stack,.GC_save_regs_in_stack_end-GC_save_regs_in_stack");
 453 #   endif
 454 #   ifdef LINT
 455         word GC_save_regs_in_stack() { return(0 /* sp really */);}
 456 #   endif
 457 # endif
 458
 459 /* On IA64, we also need to flush register windows.  But they end       */
 460 /* up on the other side of the stack segment.                           */
 461 /* Returns the backing store pointer for the register stack.            */
 462 # ifdef IA64
 463         asm("        .text");
 464         asm("        .psr abi64");
 465         asm("        .psr lsb");
 466         asm("        .lsb");
 467         asm("");
 468         asm("        .text");
 469         asm("        .align 16");
 470         asm("        .global GC_save_regs_in_stack");
 471         asm("        .proc GC_save_regs_in_stack");
 472         asm("GC_save_regs_in_stack:");
 473         asm("        .body");
 474         asm("        flushrs");
 475         asm("        ;;");
 476         asm("        mov r8=ar.bsp");
 477         asm("        br.ret.sptk.few rp");
 478         asm("        .endp GC_save_regs_in_stack");
 479 # endif
 480
 481 /* GC_clear_stack_inner(arg, limit) clears stack area up to limit and   */
 482 /* returns arg.  Stack clearing is crucial on SPARC, so we supply       */
 483 /* an assembly version that's more careful.  Assumes limit is hotter    */
 484 /* than sp, and limit is 8 byte aligned.                                */
 485 #if defined(ASM_CLEAR_CODE) && !defined(THREADS)
 486 #ifndef SPARC
 487         --> fix it
 488 #endif
 489 # ifdef SUNOS4
 490     asm(".globl _GC_clear_stack_inner");
 491     asm("_GC_clear_stack_inner:");
 492 # else
 493     asm(".globl GC_clear_stack_inner");
 494     asm("GC_clear_stack_inner:");
 495     asm(".type GC_save_regs_in_stack,#function");
 496 # endif
 497 #if defined(__arch64__) || defined(__sparcv9)
 498   asm("mov %sp,%o2");           /* Save sp                      */
 499   asm("add %sp,2047-8,%o3");    /* p = sp+bias-8                */
 500   asm("add %o1,-2047-192,%sp"); /* Move sp out of the way,      */
 501                                 /* so that traps still work.    */
 502                                 /* Includes some extra words    */
 503                                 /* so we can be sloppy below.   */
 504   asm("loop:");
 505   asm("stx %g0,[%o3]");         /* *(long *)p = 0               */
 506   asm("cmp %o3,%o1");
 507   asm("bgu,pt %xcc, loop");     /* if (p > limit) goto loop     */
 508     asm("add %o3,-8,%o3");      /* p -= 8 (delay slot) */
 509   asm("retl");
 510     asm("mov %o2,%sp");         /* Restore sp., delay slot      */
 511 #else
 512   asm("mov %sp,%o2");           /* Save sp      */
 513   asm("add %sp,-8,%o3");        /* p = sp-8     */
 514   asm("clr %g1");               /* [g0,g1] = 0  */
 515   asm("add %o1,-0x60,%sp");     /* Move sp out of the way,      */
 516                                 /* so that traps still work.    */
 517                                 /* Includes some extra words    */
 518                                 /* so we can be sloppy below.   */
 519   asm("loop:");
 520   asm("std %g0,[%o3]");         /* *(long long *)p = 0  */
 521   asm("cmp %o3,%o1");
 522   asm("bgu loop ");             /* if (p > limit) goto loop     */
 523     asm("add %o3,-8,%o3");      /* p -= 8 (delay slot) */
 524   asm("retl");
 525     asm("mov %o2,%sp");         /* Restore sp., delay slot      */
 526 #endif
 527   /* First argument = %o0 = return value */
 528 #   ifdef SVR4
 529       asm("     .GC_clear_stack_inner_end:");
 530       asm("     .size GC_clear_stack_inner,.GC_clear_stack_inner_end-GC_clear_stack_inner");
 531 #   endif
 532
 533 # ifdef LINT
 534     /*ARGSUSED*/
 535     ptr_t GC_clear_stack_inner(arg, limit)
 536     ptr_t arg; word limit;
 537     { return(arg); }
 538 # endif
 539 #endif