From 39ce0d5862cd5fab8c93d60b195610b2ac77a094 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Wed, 22 Mar 2006 16:30:50 +0000
Subject: Avoid storing precious data below the stack pointer.

---
 src/libmp/386/mpdigdiv.s       | 35 +++++++++++++++--------------------
 src/libmp/386/mpvecadd.s       | 29 +++++++++++++++--------------
 src/libmp/386/mpvecdigmuladd.s | 27 ++++++++++++++-------------
 src/libmp/386/mpvecsub.s       | 35 ++++++++++++++++++-----------------
 4 files changed, 62 insertions(+), 64 deletions(-)

diff --git a/src/libmp/386/mpdigdiv.s b/src/libmp/386/mpdigdiv.s
index f02e1616..143bba9b 100644
--- a/src/libmp/386/mpdigdiv.s
+++ b/src/libmp/386/mpdigdiv.s
@@ -1,19 +1,19 @@
 .text
-
 .p2align 2,0x90
 .globl mpdigdiv
 	.type mpdigdiv, @function
 mpdigdiv:
 	/* Prelude */
-	pushl %ebp
-	movl %ebx, -4(%esp)		/* save on stack */
-
-	movl	8(%esp), %ebx
-	movl	(%ebx), %eax
-	movl	4(%ebx), %edx
+	pushl %ebp		/* save on stack */
+	pushl %ebx
+	
+	leal 12(%esp), %ebp	/* %ebp = FP for now */
+	movl 0(%ebp), %ebx	/* dividend */
+	movl 0(%ebx), %eax
+	movl 4(%ebx), %edx
+	movl 4(%ebp), %ebx	/* divisor */
+	movl 8(%ebp), %ebp	/* quotient */
 
-	movl	12(%esp), %ebx
-	movl	16(%esp), %ebp
 	xorl	%ecx, %ecx
 	cmpl	%ebx, %edx		/* dividend >= 2^32 * divisor */
 	jae	divovfl
@@ -21,19 +21,14 @@ mpdigdiv:
 	je	divovfl
 	divl	%ebx		/* AX = DX:AX/BX */
 	movl	%eax, (%ebp)
-	jmp done
+done:
+	/* Postlude */
+	popl %ebx
+	popl %ebp
+	ret
 
 	/* return all 1's */
 divovfl:
 	notl	%ecx
 	movl	%ecx, (%ebp)
-
-done:
-	/* Postlude */
-	movl -4(%esp), %ebx		/* restore from stack */
-	movl %esp, %ebp
-	leave
-	ret
-
-.endmpdigdiv:
-	.size mpdigdiv,.endmpdigdiv-mpdigdiv
+	jmp done
diff --git a/src/libmp/386/mpvecadd.s b/src/libmp/386/mpvecadd.s
index 67519ad4..04a2bedf 100644
--- a/src/libmp/386/mpvecadd.s
+++ b/src/libmp/386/mpvecadd.s
@@ -10,17 +10,19 @@
 	.type mpvecadd, @function
 mpvecadd:
 	/* Prelude */
-	pushl %ebp
-	movl %ebx, -4(%esp)		/* save on stack */
-	movl %esi, -8(%esp)
-	movl %edi, -12(%esp)
+	pushl %ebp		/* save on stack */
+	pushl %ebx
+	pushl %esi
+	pushl %edi
 
-	movl	12(%esp), %edx		/* alen */
-	movl	20(%esp), %ecx		/* blen */
-	movl	8(%esp), %esi		/* a */
-	movl	16(%esp), %ebx		/* b */
+	leal 20(%esp), %ebp		/* %ebp = FP for now */
+
+	movl	4(%ebp), %edx		/* alen */
+	movl	12(%ebp), %ecx		/* blen */
+	movl	0(%ebp), %esi		/* a */
+	movl	8(%ebp), %ebx		/* b */
 	subl	%ecx, %edx
-	movl	24(%esp), %edi		/* sum */
+	movl	16(%ebp), %edi		/* sum */
 	xorl	%ebp, %ebp		/* this also sets carry to 0 */
 
 	/* skip addition if b is zero */
@@ -62,9 +64,8 @@ _addloop2:
 
 done:
 	/* Postlude */
-	movl -4(%esp), %ebx		/* restore from stack */
-	movl -8(%esp), %esi
-	movl -12(%esp), %edi
-	movl %esp, %ebp
-	leave
+	popl %edi
+	popl %esi
+	popl %ebx
+	popl %ebp
 	ret
diff --git a/src/libmp/386/mpvecdigmuladd.s b/src/libmp/386/mpvecdigmuladd.s
index 987c6330..7d11f2a1 100644
--- a/src/libmp/386/mpvecdigmuladd.s
+++ b/src/libmp/386/mpvecdigmuladd.s
@@ -27,15 +27,16 @@
 	.type mpvecdigmuladd, @function
 mpvecdigmuladd:
 	/* Prelude */
-	pushl %ebp
-	movl %ebx, -4(%esp)		/* save on stack */
-	movl %esi, -8(%esp)
-	movl %edi, -12(%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 */
 	movl	%ecx, %ebp
 	negl	%ebp			/* BP = -n */
 	shll	$2, %ecx
@@ -61,9 +62,9 @@ _muladdnocarry2:
 	adcl	%eax, %eax		/* return carry out of p[n] */
 
 	/* Postlude */
-	movl -4(%esp), %ebx		/* restore from stack */
-	movl -8(%esp), %esi
-	movl -12(%esp), %edi
-	movl %esp, %ebp
-	leave
+	popl %edi
+	popl %esi
+	popl %ebx
+	popl %ebp
 	ret
+
diff --git a/src/libmp/386/mpvecsub.s b/src/libmp/386/mpvecsub.s
index e94dae16..06726668 100644
--- a/src/libmp/386/mpvecsub.s
+++ b/src/libmp/386/mpvecsub.s
@@ -10,16 +10,18 @@
 	.type mpvecsub, @function
 mpvecsub:
 	/* Prelude */
-	pushl %ebp
-	movl %ebx, -4(%esp)		/* save on stack */
-	movl %esi, -8(%esp)
-	movl %edi, -12(%esp)
-
-	movl	8(%esp), %esi		/* a */
-	movl	16(%esp), %ebx		/* b */
-	movl	12(%esp), %edx		/* alen */
-	movl	20(%esp), %ecx		/* blen */
-	movl	24(%esp), %edi		/* diff */
+	pushl %ebp		/* save on stack */
+	pushl %ebx
+	pushl %esi
+	pushl %edi
+
+	leal 20(%esp), %ebp		/* %ebp = FP for now */
+	movl	0(%ebp), %esi		/* a */
+	movl	8(%ebp), %ebx		/* b */
+	movl	4(%ebp), %edx		/* alen */
+	movl	12(%ebp), %ecx		/* blen */
+	movl	16(%ebp), %edi		/* diff */
+
 	subl	%ecx,%edx
 	xorl	%ebp,%ebp			/* this also sets carry to 0 */
 
@@ -46,15 +48,14 @@ _subloop2:
 	movl	(%esi, %ebp, 4), %eax
 	sbbl	$0, %eax
 	movl	%eax, (%edi, %ebp, 4)
-	INCL	%ebp
-	LOOP	_subloop2
+	incl	%ebp
+	loop	_subloop2
 
 done:
 	/* Postlude */
-	movl -4(%esp), %ebx		/* restore from stack */
-	movl -8(%esp), %esi
-	movl -12(%esp), %edi
-	movl %esp, %ebp
-	leave
+	popl %edi
+	popl %esi
+	popl %ebx
+	popl %ebp
 	ret
 
-- 
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