src/assembly/x86-64/assem-rtns.lisp

   1 ;;;; the machine specific support routines needed by the file assembler
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!VM")
  13 \f
  14 ;;;; RETURN-MULTIPLE
  15
  16 ;;; For RETURN-MULTIPLE, we have to move the results from the end of
  17 ;;; the frame for the function that is returning to the end of the
  18 ;;; frame for the function being returned to.
  19
  20 #+sb-assembling ;; We don't want a vop for this one.
  21 (define-assembly-routine
  22     (return-multiple (:return-style :none))
  23     (;; These four are really arguments.
  24      (:temp eax unsigned-reg rax-offset)
  25      (:temp ebx unsigned-reg rbx-offset)
  26      (:temp ecx unsigned-reg rcx-offset)
  27      (:temp esi unsigned-reg rsi-offset)
  28
  29      ;; These we need as temporaries.
  30      (:temp edx unsigned-reg rdx-offset)
  31      (:temp edi unsigned-reg rdi-offset))
  32
  33   ;; Pick off the cases where everything fits in register args.
  34   (inst jrcxz ZERO-VALUES)
  35   (inst cmp ecx (fixnumize 1))
  36   (inst jmp :e ONE-VALUE)
  37   (inst cmp ecx (fixnumize 2))
  38   (inst jmp :e TWO-VALUES)
  39   (inst cmp ecx (fixnumize 3))
  40   (inst jmp :e THREE-VALUES)
  41
  42   ;; Save the count, because the loop is going to destroy it.
  43   (inst mov edx ecx)
  44
  45   ;; Blit the values down the stack. Note: there might be overlap, so
  46   ;; we have to be careful not to clobber values before we've read
  47   ;; them. Because the stack builds down, we are coping to a larger
  48   ;; address. Therefore, we need to iterate from larger addresses to
  49   ;; smaller addresses. pfw-this says copy ecx words from esi to edi
  50   ;; counting down.
  51   (inst shr ecx 3)                      ; fixnum to raw word count
  52   (inst std)                            ; count down
  53   (inst sub esi 8)                      ; ?
  54   (inst lea edi (make-ea :qword :base ebx :disp (- n-word-bytes)))
  55   (inst rep)
  56   (inst movs :qword)
  57   (inst cld)
  58
  59   ;; Restore the count.
  60   (inst mov ecx edx)
  61
  62   ;; Set the stack top to the last result.
  63   (inst lea rsp-tn (make-ea :qword :base edi :disp n-word-bytes))
  64
  65   ;; Load the register args.
  66   (loadw edx ebx -1)
  67   (loadw edi ebx -2)
  68   (loadw esi ebx -3)
  69
  70   ;; And back we go.
  71   (inst stc)
  72   (inst jmp eax)
  73
  74   ;; Handle the register arg cases.
  75   ZERO-VALUES
  76   (move rsp-tn ebx)
  77   (inst mov edx nil-value)
  78   (inst mov edi edx)
  79   (inst mov esi edx)
  80   (inst stc)
  81   (inst jmp eax)
  82
  83   ONE-VALUE ; Note: we can get this, because the return-multiple vop
  84             ; doesn't check for this case when size > speed.
  85   (loadw edx esi -1)
  86   (inst mov rsp-tn ebx)
  87   (inst clc)
  88   (inst jmp eax)
  89
  90   TWO-VALUES
  91   (loadw edx esi -1)
  92   (loadw edi esi -2)
  93   (inst mov esi nil-value)
  94   (inst lea rsp-tn (make-ea :qword :base ebx :disp (* -2 n-word-bytes)))
  95   (inst stc)
  96   (inst jmp eax)
  97
  98   THREE-VALUES
  99   (loadw edx esi -1)
 100   (loadw edi esi -2)
 101   (loadw esi esi -3)
 102   (inst lea rsp-tn (make-ea :qword :base ebx :disp (* -3 n-word-bytes)))
 103   (inst stc)
 104   (inst jmp eax))
 105 \f
 106 ;;;; TAIL-CALL-VARIABLE
 107
 108 ;;; For tail-call-variable, we have to copy the arguments from the end
 109 ;;; of our stack frame (were args are produced) to the start of our
 110 ;;; stack frame (were args are expected).
 111 ;;;
 112 ;;; We take the function to call in EAX and a pointer to the arguments in
 113 ;;; ESI. EBP says the same over the jump, and the old frame pointer is
 114 ;;; still saved in the first stack slot. The return-pc is saved in
 115 ;;; the second stack slot, so we have to push it to make it look like
 116 ;;; we actually called. We also have to compute ECX from the difference
 117 ;;; between ESI and the stack top.
 118 #+sb-assembling ;; No vop for this one either.
 119 (define-assembly-routine
 120     (tail-call-variable
 121      (:return-style :none))
 122
 123     ((:temp eax unsigned-reg rax-offset)
 124      (:temp ebx unsigned-reg rbx-offset)
 125      (:temp ecx unsigned-reg rcx-offset)
 126      (:temp edx unsigned-reg rdx-offset)
 127      (:temp edi unsigned-reg rdi-offset)
 128      (:temp esi unsigned-reg rsi-offset))
 129
 130   ;; Calculate NARGS (as a fixnum)
 131   (move ecx esi)
 132   (inst sub ecx rsp-tn)
 133
 134   ;; Check for all the args fitting the registers.
 135   (inst cmp ecx (fixnumize 3))
 136   (inst jmp :le REGISTER-ARGS)
 137
 138   ;; Save the OLD-FP and RETURN-PC because the blit it going to trash
 139   ;; those stack locations. Save the ECX, because the loop is going
 140   ;; to trash it.
 141   (pushw rbp-tn -1)
 142   (loadw ebx rbp-tn -2)
 143   (inst push ecx)
 144
 145   ;; Do the blit. Because we are coping from smaller addresses to
 146   ;; larger addresses, we have to start at the largest pair and work
 147   ;; our way down.
 148   (inst shr ecx 3)                      ; fixnum to raw words
 149   (inst std)                            ; count down
 150   (inst lea edi (make-ea :qword :base rbp-tn :disp (- n-word-bytes)))
 151   (inst sub esi (fixnumize 1))
 152   (inst rep)
 153   (inst movs :qword)
 154   (inst cld)
 155
 156   ;; Load the register arguments carefully.
 157   (loadw edx rbp-tn -1)
 158
 159   ;; Restore OLD-FP and ECX.
 160   (inst pop ecx)
 161   (popw rbp-tn -1)                      ; overwrites a0
 162
 163   ;; Blow off the stack above the arguments.
 164   (inst lea rsp-tn (make-ea :qword :base edi :disp n-word-bytes))
 165
 166   ;; remaining register args
 167   (loadw edi rbp-tn -2)
 168   (loadw esi rbp-tn -3)
 169
 170   ;; Push the (saved) return-pc so it looks like we just called.
 171   (inst push ebx)
 172
 173   ;; And jump into the function.
 174   (inst jmp
 175         (make-ea :byte :base eax
 176                  :disp (- (* closure-fun-slot n-word-bytes)
 177                           fun-pointer-lowtag)))
 178
 179   ;; All the arguments fit in registers, so load them.
 180   REGISTER-ARGS
 181   (loadw edx esi -1)
 182   (loadw edi esi -2)
 183   (loadw esi esi -3)
 184
 185   ;; Clear most of the stack.
 186   (inst lea rsp-tn
 187         (make-ea :qword :base rbp-tn :disp (* -3 n-word-bytes)))
 188
 189   ;; Push the return-pc so it looks like we just called.
 190   (pushw rbp-tn -2)    ; XXX dan ?
 191
 192   ;; And away we go.
 193   (inst jmp (make-ea :byte :base eax
 194                      :disp (- (* closure-fun-slot n-word-bytes)
 195                               fun-pointer-lowtag))))
 196 \f
 197 (define-assembly-routine (throw
 198                           (:return-style :none))
 199                          ((:arg target (descriptor-reg any-reg) rdx-offset)
 200                           (:arg start any-reg rbx-offset)
 201                           (:arg count any-reg rcx-offset)
 202                           (:temp catch any-reg rax-offset))
 203
 204   (declare (ignore start count))
 205
 206   (load-tl-symbol-value catch *current-catch-block*)
 207
 208   LOOP
 209
 210   (let ((error (generate-error-code nil 'unseen-throw-tag-error target)))
 211     (inst or catch catch)               ; check for NULL pointer
 212     (inst jmp :z error))
 213
 214   (inst cmp target (make-ea-for-object-slot catch catch-block-tag-slot 0))
 215   (inst jmp :e EXIT)
 216
 217   (loadw catch catch catch-block-previous-catch-slot)
 218   (inst jmp LOOP)
 219
 220   EXIT
 221
 222   ;; Here EAX points to catch block containing symbol pointed to by EDX.
 223   (inst jmp (make-fixup 'unwind :assembly-routine)))
 224
 225 ;;;; non-local exit noise
 226
 227 (define-assembly-routine (unwind
 228                           (:return-style :none)
 229                           (:translate %continue-unwind)
 230                           (:policy :fast-safe))
 231                          ((:arg block (any-reg descriptor-reg) rax-offset)
 232                           (:arg start (any-reg descriptor-reg) rbx-offset)
 233                           (:arg count (any-reg descriptor-reg) rcx-offset)
 234                           (:temp uwp unsigned-reg rsi-offset))
 235   (declare (ignore start count))
 236
 237   (let ((error (generate-error-code nil 'invalid-unwind-error)))
 238     (inst or block block)               ; check for NULL pointer
 239     (inst jmp :z error))
 240
 241   (load-tl-symbol-value uwp *current-unwind-protect-block*)
 242
 243   ;; Does *CURRENT-UNWIND-PROTECT-BLOCK* match the value stored in
 244   ;; argument's CURRENT-UWP-SLOT?
 245   (inst cmp uwp
 246         (make-ea-for-object-slot block unwind-block-current-uwp-slot 0))
 247   ;; If a match, return to context in arg block.
 248   (inst jmp :e DO-EXIT)
 249
 250   ;; Not a match - return to *CURRENT-UNWIND-PROTECT-BLOCK* context.
 251   ;; Important! Must save (and return) the arg 'block' for later use!!
 252   (move rdx-tn block)
 253   (move block uwp)
 254   ;; Set next unwind protect context.
 255   (loadw uwp uwp unwind-block-current-uwp-slot)
 256   ;; we're about to reload ebp anyway, so let's borrow it here as a
 257   ;; temporary.  Hope this works
 258   (store-tl-symbol-value uwp *current-unwind-protect-block* rbp-tn)
 259
 260   DO-EXIT
 261
 262   (loadw rbp-tn block unwind-block-current-cont-slot)
 263
 264   ;; Uwp-entry expects some things in known locations so that they can
 265   ;; be saved on the stack: the block in edx-tn, start in ebx-tn, and
 266   ;; count in ecx-tn.
 267
 268   (inst jmp (make-ea :byte :base block
 269                      :disp (* unwind-block-entry-pc-slot n-word-bytes))))