Avoid saving precious data under stack pointer.

1 files changed, 18 insertions, 25 deletions

diff --git a/src/libmp/386/mpvecdigmulsub.s b/src/libmp/386/mpvecdigmulsub.s
index 47089c87..f2a3a898 100644
--- a/src/libmp/386/mpvecdigmulsub.s
+++ b/src/libmp/386/mpvecdigmulsub.s
@@ -23,32 +23,27 @@
  */
 .text
 
-/* XXX: had to use "-4(%esp)" kludge to get around inability to
- *      push/pop without first adjusting %esp.  This may not be
- *      as fast as using push/pop (and accessing pushed element
- *      with "(%esp)".)
- */
-
 .p2align 2,0x90
 .globl mpvecdigmulsub
 	.type mpvecdigmulsub, @function
 mpvecdigmulsub:
 	/* Prelude */
-	pushl %ebp
-	movl %ebx, -8(%esp)		/* save on stack */
-	movl %esi, -12(%esp)
-	movl %edi, -16(%esp)
+	pushl %ebp		/* save on stack */
+	pushl %ebx
+	pushl %esi
+	pushl %edi
 
-	movl	8(%esp), %esi		/* b */
-	movl	12(%esp), %ecx		/* n */
-	movl	16(%esp), %ebx		/* m */
-	movl	20(%esp), %edi		/* p */
+	leal 20(%esp), %ebp		/* %ebp = FP for now */
+	movl	0(%ebp), %esi		/* b */
+	movl	4(%ebp), %ecx		/* n */
+	movl	8(%ebp), %ebx		/* m */
+	movl	12(%ebp), %edi		/* p */
 	xorl	%ebp, %ebp
-	movl	%ebp, -4(%esp)
+	pushl %ebp
 _mulsubloop:
 	movl	(%esi, %ebp, 4),%eax	/* lo = b[i] */
 	mull	%ebx			/* hi, lo = b[i] * m */
-	addl	-4(%esp), %eax		/* lo += oldhi */
+	addl	0(%esp), %eax		/* lo += oldhi */
 	jae	_mulsubnocarry1
 	incl	%edx			/* hi += carry */
 _mulsubnocarry1:
@@ -56,23 +51,21 @@ _mulsubnocarry1:
 	jae	_mulsubnocarry2
 	incl	%edx			/* hi += carry */
 _mulsubnocarry2:
-	movl	%edx, -4(%esp)
+	movl	%edx, 0(%esp)
 	incl	%ebp
 	loop	_mulsubloop
-	movl	-4(%esp), %eax
+	popl %eax
 	subl	%eax, (%edi, %ebp, 4)
 	jae	_mulsubnocarry3
 	movl	$-1, %eax
 	jmp done
-
 _mulsubnocarry3:
 	movl	$1, %eax
-
 done:
 	/* Postlude */
-	movl -8(%esp), %ebx		/* restore from stack */
-	movl -12(%esp), %esi
-	movl -16(%esp), %edi
-	movl %esp, %ebp
-	leave
+	popl %edi
+	popl %esi
+	popl %ebx
+	popl %ebp
 	ret
+