tAvoid storing precious data below the stack pointer. - plan9port - [fork] Plan 9 from user space
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---
DIR commit 39ce0d5862cd5fab8c93d60b195610b2ac77a094
DIR parent aff51ee51f0bab35fca95569c639042de8acf777
HTML Author: rsc <devnull@localhost>
Date: Wed, 22 Mar 2006 16:30:50 +0000
Avoid storing precious data below the stack pointer.
Diffstat:
M src/libmp/386/mpdigdiv.s | 35 +++++++++++++------------------
M src/libmp/386/mpvecadd.s | 29 +++++++++++++++--------------
M src/libmp/386/mpvecdigmuladd.s | 27 ++++++++++++++-------------
M src/libmp/386/mpvecsub.s | 35 ++++++++++++++++---------------
4 files changed, 62 insertions(+), 64 deletions(-)
---
DIR diff --git a/src/libmp/386/mpdigdiv.s b/src/libmp/386/mpdigdiv.s
t@@ -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
t@@ -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
DIR diff --git a/src/libmp/386/mpvecadd.s b/src/libmp/386/mpvecadd.s
t@@ -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 */
t@@ -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
DIR diff --git a/src/libmp/386/mpvecdigmuladd.s b/src/libmp/386/mpvecdigmuladd.s
t@@ -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
t@@ -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
+
DIR diff --git a/src/libmp/386/mpvecsub.s b/src/libmp/386/mpvecsub.s
t@@ -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 */
t@@ -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