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/* Pentium optimized __mpn_lshift --
Copyright (C) 1992-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include "sysdep.h"
#include "asm-syntax.h"
#define PARMS 4+16 /* space for 4 saved regs */
#define RES PARMS
#define S RES+4
#define SIZE S+4
#define CNT SIZE+4
.text
ENTRY (__mpn_lshift)
pushl %edi
cfi_adjust_cfa_offset (4)
pushl %esi
cfi_adjust_cfa_offset (4)
pushl %ebp
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebp, 0)
pushl %ebx
cfi_adjust_cfa_offset (4)
movl RES(%esp),%edi
cfi_rel_offset (edi, 12)
movl S(%esp),%esi
cfi_rel_offset (esi, 8)
movl SIZE(%esp),%ebx
cfi_rel_offset (ebx, 0)
movl CNT(%esp),%ecx
/* We can use faster code for shift-by-1 under certain conditions. */
cmp $1,%ecx
jne L(normal)
leal 4(%esi),%eax
cmpl %edi,%eax
jnc L(special) /* jump if s_ptr + 1 >= res_ptr */
leal (%esi,%ebx,4),%eax
cmpl %eax,%edi
jnc L(special) /* jump if res_ptr >= s_ptr + size */
L(normal):
leal -4(%edi,%ebx,4),%edi
leal -4(%esi,%ebx,4),%esi
movl (%esi),%edx
subl $4,%esi
xorl %eax,%eax
shldl %cl,%edx,%eax /* compute carry limb */
pushl %eax /* push carry limb onto stack */
cfi_adjust_cfa_offset (4)
decl %ebx
pushl %ebx
cfi_adjust_cfa_offset (4)
shrl $3,%ebx
jz L(end)
movl (%edi),%eax /* fetch destination cache line */
ALIGN (2)
L(oop): movl -28(%edi),%eax /* fetch destination cache line */
movl %edx,%ebp
movl (%esi),%eax
movl -4(%esi),%edx
shldl %cl,%eax,%ebp
shldl %cl,%edx,%eax
movl %ebp,(%edi)
movl %eax,-4(%edi)
movl -8(%esi),%ebp
movl -12(%esi),%eax
shldl %cl,%ebp,%edx
shldl %cl,%eax,%ebp
movl %edx,-8(%edi)
movl %ebp,-12(%edi)
movl -16(%esi),%edx
movl -20(%esi),%ebp
shldl %cl,%edx,%eax
shldl %cl,%ebp,%edx
movl %eax,-16(%edi)
movl %edx,-20(%edi)
movl -24(%esi),%eax
movl -28(%esi),%edx
shldl %cl,%eax,%ebp
shldl %cl,%edx,%eax
movl %ebp,-24(%edi)
movl %eax,-28(%edi)
subl $32,%esi
subl $32,%edi
decl %ebx
jnz L(oop)
L(end): popl %ebx
cfi_adjust_cfa_offset (-4)
andl $7,%ebx
jz L(end2)
L(oop2):
movl (%esi),%eax
shldl %cl,%eax,%edx
movl %edx,(%edi)
movl %eax,%edx
subl $4,%esi
subl $4,%edi
decl %ebx
jnz L(oop2)
L(end2):
shll %cl,%edx /* compute least significant limb */
movl %edx,(%edi) /* store it */
popl %eax /* pop carry limb */
cfi_adjust_cfa_offset (-4)
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
popl %ebp
cfi_adjust_cfa_offset (-4)
cfi_restore (ebp)
popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (esi)
popl %edi
cfi_adjust_cfa_offset (-4)
cfi_restore (edi)
ret
/* We loop from least significant end of the arrays, which is only
permissible if the source and destination don't overlap, since the
function is documented to work for overlapping source and destination.
*/
cfi_adjust_cfa_offset (16)
cfi_rel_offset (edi, 12)
cfi_rel_offset (esi, 8)
cfi_rel_offset (ebp, 4)
cfi_rel_offset (ebx, 0)
L(special):
movl (%esi),%edx
addl $4,%esi
decl %ebx
pushl %ebx
cfi_adjust_cfa_offset (4)
shrl $3,%ebx
addl %edx,%edx
incl %ebx
decl %ebx
jz L(Lend)
movl (%edi),%eax /* fetch destination cache line */
ALIGN (2)
L(Loop):
movl 28(%edi),%eax /* fetch destination cache line */
movl %edx,%ebp
movl (%esi),%eax
movl 4(%esi),%edx
adcl %eax,%eax
movl %ebp,(%edi)
adcl %edx,%edx
movl %eax,4(%edi)
movl 8(%esi),%ebp
movl 12(%esi),%eax
adcl %ebp,%ebp
movl %edx,8(%edi)
adcl %eax,%eax
movl %ebp,12(%edi)
movl 16(%esi),%edx
movl 20(%esi),%ebp
adcl %edx,%edx
movl %eax,16(%edi)
adcl %ebp,%ebp
movl %edx,20(%edi)
movl 24(%esi),%eax
movl 28(%esi),%edx
adcl %eax,%eax
movl %ebp,24(%edi)
adcl %edx,%edx
movl %eax,28(%edi)
leal 32(%esi),%esi /* use leal not to clobber carry */
leal 32(%edi),%edi
decl %ebx
jnz L(Loop)
L(Lend):
popl %ebx
cfi_adjust_cfa_offset (-4)
sbbl %eax,%eax /* save carry in %eax */
andl $7,%ebx
jz L(Lend2)
addl %eax,%eax /* restore carry from eax */
L(Loop2):
movl %edx,%ebp
movl (%esi),%edx
adcl %edx,%edx
movl %ebp,(%edi)
leal 4(%esi),%esi /* use leal not to clobber carry */
leal 4(%edi),%edi
decl %ebx
jnz L(Loop2)
jmp L(L1)
L(Lend2):
addl %eax,%eax /* restore carry from eax */
L(L1): movl %edx,(%edi) /* store last limb */
sbbl %eax,%eax
negl %eax
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
popl %ebp
cfi_adjust_cfa_offset (-4)
cfi_restore (ebp)
popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (esi)
popl %edi
cfi_adjust_cfa_offset (-4)
cfi_restore (edi)
ret
END (__mpn_lshift)
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