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Avoid saving precious data under stack pointer.

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rsc 2006-03-22 16:38:29 +00:00
parent 39ce0d5862
commit bdc14ad478
1 changed files with 18 additions and 25 deletions
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43
src/libmp/386/mpvecdigmulsub.s
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@ -23,32 +23,27 @@
*/ */
.text .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 .p2align 2,0x90
.globl mpvecdigmulsub .globl mpvecdigmulsub
.type mpvecdigmulsub, @function .type mpvecdigmulsub, @function
mpvecdigmulsub: mpvecdigmulsub:
/* Prelude */ /* Prelude */
pushl %ebp pushl %ebp /* save on stack */
movl %ebx, -8(%esp) /* save on stack */ pushl %ebx
movl %esi, -12(%esp) pushl %esi
movl %edi, -16(%esp) pushl %edi
movl 8(%esp), %esi /* b */ leal 20(%esp), %ebp /* %ebp = FP for now */
movl 12(%esp), %ecx /* n */ movl 0(%ebp), %esi /* b */
movl 16(%esp), %ebx /* m */ movl 4(%ebp), %ecx /* n */
movl 20(%esp), %edi /* p */ movl 8(%ebp), %ebx /* m */
movl 12(%ebp), %edi /* p */
xorl %ebp, %ebp xorl %ebp, %ebp
movl %ebp, -4(%esp) pushl %ebp
_mulsubloop: _mulsubloop:
movl (%esi, %ebp, 4),%eax /* lo = b[i] */ movl (%esi, %ebp, 4),%eax /* lo = b[i] */
mull %ebx /* hi, lo = b[i] * m */ mull %ebx /* hi, lo = b[i] * m */
addl -4(%esp), %eax /* lo += oldhi */ addl 0(%esp), %eax /* lo += oldhi */
jae _mulsubnocarry1 jae _mulsubnocarry1
incl %edx /* hi += carry */ incl %edx /* hi += carry */
_mulsubnocarry1: _mulsubnocarry1:
@ -56,23 +51,21 @@ _mulsubnocarry1:
jae _mulsubnocarry2 jae _mulsubnocarry2
incl %edx /* hi += carry */ incl %edx /* hi += carry */
_mulsubnocarry2: _mulsubnocarry2:
movl %edx, -4(%esp) movl %edx, 0(%esp)
incl %ebp incl %ebp
loop _mulsubloop loop _mulsubloop
movl -4(%esp), %eax popl %eax
subl %eax, (%edi, %ebp, 4) subl %eax, (%edi, %ebp, 4)
jae _mulsubnocarry3 jae _mulsubnocarry3
movl $-1, %eax movl $-1, %eax
jmp done jmp done
_mulsubnocarry3: _mulsubnocarry3:
movl $1, %eax movl $1, %eax
done: done:
/* Postlude */ /* Postlude */
movl -8(%esp), %ebx /* restore from stack */ popl %edi
movl -12(%esp), %esi popl %esi
movl -16(%esp), %edi popl %ebx
movl %esp, %ebp popl %ebp
leave
ret ret