(in-package "SB!VM")
+;;; The :full-call assembly-routines must use the same full-call
+;;; unknown-values return convention as a normal call, as some
+;;; of the routines will tail-chain to a static-function. The
+;;; routines themselves, however, take all of their arguments
+;;; in registers (this will typically be one or two arguments,
+;;; and is one of the lower bounds on the number of argument-
+;;; passing registers), and thus don't need a call frame, which
+;;; simplifies things for the normal call/return case. When it
+;;; is neccessary for one of the assembly-functions to call a
+;;; static-function it will construct the required call frame.
+;;; Also, none of the assembly-routines return other than one
+;;; value, which again simplifies the return path.
+;;; -- AB, 2006/Feb/05.
+
(!def-vm-support-routine generate-call-sequence (name style vop)
(ecase style
((:raw :none)
(:full-call
(values
`((note-this-location ,vop :call-site)
- (inst call (make-fixup ',name :assembly-routine))
- (note-this-location ,vop :single-value-return)
- (move esp-tn ebx-tn))
+ (inst call (make-fixup ',name :assembly-routine))
+ (note-this-location ,vop :single-value-return)
+ (cond
+ ((member :cmov *backend-subfeatures*)
+ (inst cmov :c esp-tn ebx-tn))
+ (t
+ (let ((single-value (gen-label)))
+ (inst jmp :nc single-value)
+ (move esp-tn ebx-tn)
+ (emit-label single-value)))))
'((:save-p :compute-only))))))
(!def-vm-support-routine generate-return-sequence (style)
(:raw
`(inst ret))
(:full-call
- `(
- (inst pop eax-tn)
-
- (inst add eax-tn 2)
- (inst jmp eax-tn)))
+ `((inst clc)
+ (inst ret)))
(:none)))