- (emit-label single-value)))))
- ((<= nvals register-arg-count)
- (let ((regs-defaulted (gen-label)))
- (note-this-location vop :unknown-return)
- (inst jmp :c regs-defaulted)
- ;; Default the unsupplied registers.
- (let* ((2nd-tn-ref (tn-ref-across values))
- (2nd-tn (tn-ref-tn 2nd-tn-ref)))
- (inst mov 2nd-tn nil-value)
- (when (> nvals 2)
- (loop
- for tn-ref = (tn-ref-across 2nd-tn-ref)
- then (tn-ref-across tn-ref)
- for count from 2 below register-arg-count
- do (inst mov (tn-ref-tn tn-ref) 2nd-tn))))
- (inst mov ebx-tn esp-tn)
- (emit-label regs-defaulted)
- (inst mov esp-tn ebx-tn)))
- ((<= nvals 7)
- ;; The number of bytes depends on the relative jump instructions.
- ;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
- ;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
- ;; bytes which is likely better than using the blt below.
- (let ((regs-defaulted (gen-label))
- (defaulting-done (gen-label))
- (default-stack-slots (gen-label)))
- (note-this-location vop :unknown-return)
- ;; Branch off to the MV case.
- (inst jmp :c regs-defaulted)
- ;; Do the single value case.
- ;; Default the register args
- (inst mov eax-tn nil-value)
- (do ((i 1 (1+ i))
- (val (tn-ref-across values) (tn-ref-across val)))
- ((= i (min nvals register-arg-count)))
- (inst mov (tn-ref-tn val) eax-tn))
-
- ;; Fake other registers so it looks like we returned with all the
- ;; registers filled in.
- (move ebx-tn esp-tn)
- (inst jmp default-stack-slots)
-
- (emit-label regs-defaulted)
-
- (inst mov eax-tn nil-value)
- (collect ((defaults))
- (do ((i register-arg-count (1+ i))
- (val (do ((i 0 (1+ i))
- (val values (tn-ref-across val)))
- ((= i register-arg-count) val))
- (tn-ref-across val)))
- ((null val))
- (let ((default-lab (gen-label))
- (tn (tn-ref-tn val))
- (first-stack-arg-p (= i register-arg-count)))
- (defaults (cons default-lab (cons tn first-stack-arg-p)))
-
- (inst cmp ecx-tn (fixnumize i))
- (inst jmp :be default-lab)
- (when first-stack-arg-p
- ;; There are stack args so the frame of the callee is
- ;; still there, save EDX in its first slot temporalily.
- (storew edx-tn ebx-tn (frame-word-offset sp->fp-offset)))
- (loadw edx-tn ebx-tn (frame-word-offset (+ sp->fp-offset i)))
- (inst mov tn edx-tn)))
-
- (emit-label defaulting-done)
- (loadw edx-tn ebx-tn (frame-word-offset sp->fp-offset))
- (move esp-tn ebx-tn)
-
- (let ((defaults (defaults)))
- (when defaults
- (assemble (*elsewhere*)
- (trace-table-entry trace-table-fun-prologue)
- (emit-label default-stack-slots)
- (dolist (default defaults)
- (emit-label (car default))
- (when (cddr default)
- ;; We are setting the first stack argument to NIL.
- ;; The callee's stack frame is dead, save EDX by
- ;; pushing it to the stack, it will end up at same
- ;; place as in the (STOREW EDX-TN EBX-TN -1) case
- ;; above.
- (inst push edx-tn))
- (inst mov (second default) eax-tn))
- (inst jmp defaulting-done)
- (trace-table-entry trace-table-normal)))))))
- (t
- ;; 91 bytes for this branch.
- (let ((regs-defaulted (gen-label))
- (restore-edi (gen-label))
- (no-stack-args (gen-label))
- (default-stack-vals (gen-label))
- (count-okay (gen-label)))
- (note-this-location vop :unknown-return)
- ;; Branch off to the MV case.
- (inst jmp :c regs-defaulted)
-
- ;; Default the register args, and set up the stack as if we
- ;; entered the MV return point.
- (inst mov ebx-tn esp-tn)
- (inst mov edi-tn nil-value)
- (inst mov esi-tn edi-tn)
- ;; Compute a pointer to where to put the [defaulted] stack values.
- (emit-label no-stack-args)
- (inst push edx-tn)
- (inst push edi-tn)
- (inst lea edi-tn
- (make-ea :dword :base ebp-tn
- :disp (frame-byte-offset register-arg-count)))
- ;; Load EAX with NIL so we can quickly store it, and set up
- ;; stuff for the loop.
- (inst mov eax-tn nil-value)
- (inst std)
- (inst mov ecx-tn (- nvals register-arg-count))
- ;; Jump into the default loop.
- (inst jmp default-stack-vals)
-
- ;; The regs are defaulted. We need to copy any stack arguments,
- ;; and then default the remaining stack arguments.
- (emit-label regs-defaulted)
- ;; Save EDI.
- (storew edi-tn ebx-tn (frame-word-offset (+ sp->fp-offset 1)))
- ;; Compute the number of stack arguments, and if it's zero or
- ;; less, don't copy any stack arguments.
- (inst sub ecx-tn (fixnumize register-arg-count))
- (inst jmp :le no-stack-args)
-
- ;; Throw away any unwanted args.
- (inst cmp ecx-tn (fixnumize (- nvals register-arg-count)))
- (inst jmp :be count-okay)
- (inst mov ecx-tn (fixnumize (- nvals register-arg-count)))
- (emit-label count-okay)
- ;; Save the number of stack values.
- (inst mov eax-tn ecx-tn)
- ;; Compute a pointer to where the stack args go.
- (inst lea edi-tn
- (make-ea :dword :base ebp-tn
- :disp (frame-byte-offset register-arg-count)))
- ;; Save ESI, and compute a pointer to where the args come from.
- (storew esi-tn ebx-tn (frame-word-offset (+ sp->fp-offset 2)))
- (inst lea esi-tn
- (make-ea :dword :base ebx-tn
- :disp (frame-byte-offset
- (+ sp->fp-offset register-arg-count))))
- ;; Do the copy.
- (inst shr ecx-tn word-shift) ; make word count
- (inst std)
- (inst rep)
- (inst movs :dword)
- ;; Restore ESI.
- (loadw esi-tn ebx-tn (frame-word-offset (+ sp->fp-offset 2)))
- ;; Now we have to default the remaining args. Find out how many.
- (inst sub eax-tn (fixnumize (- nvals register-arg-count)))
- (inst neg eax-tn)
- ;; If none, then just blow out of here.
- (inst jmp :le restore-edi)
- (inst mov ecx-tn eax-tn)
- (inst shr ecx-tn word-shift) ; word count
- ;; Load EAX with NIL for fast storing.
- (inst mov eax-tn nil-value)
- ;; Do the store.
- (emit-label default-stack-vals)
- (inst rep)
- (inst stos eax-tn)
- ;; Restore EDI, and reset the stack.
- (emit-label restore-edi)
- (loadw edi-tn ebx-tn (frame-word-offset (+ sp->fp-offset 1)))
- (inst mov esp-tn ebx-tn)
- (inst cld))))