[git] CMU Common Lisp branch master updated. begin-x87-removal-6-g260d94f

[Raymond Toy]

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- Log -----------------------------------------------------------------
commit 260d94f1a9057fb9ae592a0b7b898f881316f289
Author: Raymond Toy <toy.raymond at gmail.com>
Date:   Thu Apr 10 20:03:20 2014 -0700

    Simplify call_into_c more, putting more of the functionality into
    call-out.
    
     * lisp/x86-assem.S
       * Rip out all of cruft dealing with float return values and the
         need for maintaining the FPU state.  Just call the foreign
         function and return, letting call-out deal with the result.
     * compiler/x86/sse2-c-call.lisp
       * Handle the different return values depending on whether we
         declared the function to return a float or not.

diff --git a/src/compiler/x86/sse2-c-call.lisp b/src/compiler/x86/sse2-c-call.lisp
index edd226b..83f21b5 100644
--- a/src/compiler/x86/sse2-c-call.lisp
+++ b/src/compiler/x86/sse2-c-call.lisp
@@ -44,35 +44,26 @@
   (:generator 0 
     (cond ((policy node (> space speed))
 	   (move eax function)
-	   (inst call (make-fixup (extern-alien-name "call_into_c") :foreign))
-	   (when (and results (location= (tn-ref-tn results) xmm0-tn))
-	     ;; If there is a float result from the foreign call,
-	     ;; call_into_c has arranged for the result to be in XMM0,
-	     ;; as a double. If we wanted a single float, do the
-	     ;; conversion here.
-	     (sc-case (tn-ref-tn results)
-	       (single-reg
-		(inst cvtsd2ss xmm0-tn xmm0-tn))
-	       (double-reg
-		;; Nothing needed for double because call_into_c saved
-		;; the result as a double.
-		))))
+	   (inst call (make-fixup (extern-alien-name "call_into_c") :foreign)))
 	  (t
 	   (inst call function)
 	   ;; To give the debugger a clue. XX not really internal-error?
-	   (note-this-location vop :internal-error)
-
-	   (when (and results
-		      (location= (tn-ref-tn results) xmm0-tn))
-	     ;; If there's a float result, it would have been returned
-	     ;; in fr0 according to the ABI. We want it in xmm0.
-	     (sc-case (tn-ref-tn results)
-	       (single-reg
-		(inst fstp (ea-for-sf-stack temp-single))
-		(inst movss xmm0-tn (ea-for-sf-stack temp-single)))
-	       (double-reg
-		(inst fstpd (ea-for-df-stack temp-double))
-		(inst movsd xmm0-tn (ea-for-df-stack temp-double)))))))))
+	   (note-this-location vop :internal-error)))
+    ;; FIXME: check that a float result is returned when expected. If
+    ;; we don't, we'll either get a NaN when doing the fstp or we'll
+    ;; leave an entry on the FPU and we'll eventually overflow the FPU
+    ;; stack.
+    (when (and results
+	       (location= (tn-ref-tn results) xmm0-tn))
+      ;; If there's a float result, it would have been returned
+      ;; in ST(0) according to the ABI. We want it in xmm0.
+      (sc-case (tn-ref-tn results)
+	(single-reg
+	 (inst fstp (ea-for-sf-stack temp-single))
+	 (inst movss xmm0-tn (ea-for-sf-stack temp-single)))
+	(double-reg
+	 (inst fstpd (ea-for-df-stack temp-double))
+	 (inst movsd xmm0-tn (ea-for-df-stack temp-double)))))))
 
 (define-vop (alloc-number-stack-space)
   (:info amount)
diff --git a/src/lisp/x86-assem.S b/src/lisp/x86-assem.S
index b01fa5f..f9dee43 100644
--- a/src/lisp/x86-assem.S
+++ b/src/lisp/x86-assem.S
@@ -100,42 +100,10 @@ FUNCDEF(call_into_c)
 
 	call	*%eax		# normal callout using Lisp stack
 
-	movl	%eax,%ecx	# remember integer return value
-
-/* Check for a return FP value */
-	fxam
-	fnstsw	%ax
-	andl	$0x4500,%eax
-	cmpl	$0x4100,%eax
-	jne	Lfp_rtn_value
-
-/* The return value is in eax, or eax,edx? */
-no_fldz:	
-/* Restore the return value */
-	movl	%ecx,%eax	# maybe return value
-
 	movl	$0,GNAME(foreign_function_call_active)
 /* Return */	
 	jmp	*%ebx
 
-Lfp_rtn_value:
-
-/* 
- * The float result is in st(0).  We want it in xmm0.  For
- * consistency, save st(0) out as a double and load it into xmm0 as a
- * double.  The call-out vop will arrange to convert it to a single-float
- * if necessary.
- */
-	subl	$8, %esp	# Space for a double float
-	fstpl	0(%esp)
-	movsd	0(%esp), %xmm0
-	addl	$8, %esp
-
-/* Don't need to restore eax as the result is in st(0) */
-
-	movl	$0,GNAME(foreign_function_call_active)
-/* Return */	
-	jmp	*%ebx
 ENDFUNC(call_into_c)
 
 

-----------------------------------------------------------------------

Summary of changes:
 src/compiler/x86/sse2-c-call.lisp |   43 +++++++++++++++----------------------
 src/lisp/x86-assem.S              |   32 ---------------------------
 2 files changed, 17 insertions(+), 58 deletions(-)


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