mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-11 13:50:06 +00:00
175 lines
3.8 KiB
ArmAsm
175 lines
3.8 KiB
ArmAsm
/* Optimized strcmp implementation for POWER7/PowerPC32.
|
|
Copyright (C) 2010-2013 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
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <sysdep.h>
|
|
|
|
/* See strlen.s for comments on how the end-of-string testing works. */
|
|
|
|
/* int [r3] strncmp (const char *s1 [r3],
|
|
const char *s2 [r4],
|
|
size_t size [r5]) */
|
|
|
|
EALIGN (strncmp,5,0)
|
|
|
|
#define rTMP r0
|
|
#define rRTN r3
|
|
#define rSTR1 r3 /* first string arg */
|
|
#define rSTR2 r4 /* second string arg */
|
|
#define rN r5 /* max string length */
|
|
#define rWORD1 r6 /* current word in s1 */
|
|
#define rWORD2 r7 /* current word in s2 */
|
|
#define rWORD3 r10
|
|
#define rWORD4 r11
|
|
#define rFEFE r8 /* constant 0xfefefeff (-0x01010101) */
|
|
#define r7F7F r9 /* constant 0x7f7f7f7f */
|
|
#define rNEG r10 /* ~(word in s1 | 0x7f7f7f7f) */
|
|
#define rBITDIF r11 /* bits that differ in s1 & s2 words */
|
|
|
|
dcbt 0,rSTR1
|
|
nop
|
|
or rTMP,rSTR2,rSTR1
|
|
lis r7F7F,0x7f7f
|
|
dcbt 0,rSTR2
|
|
nop
|
|
clrlwi. rTMP,rTMP,30
|
|
cmplwi cr1,rN,0
|
|
lis rFEFE,-0x101
|
|
bne L(unaligned)
|
|
/* We are word aligned so set up for two loops. first a word
|
|
loop, then fall into the byte loop if any residual. */
|
|
srwi. rTMP,rN,2
|
|
clrlwi rN,rN,30
|
|
addi rFEFE,rFEFE,-0x101
|
|
addi r7F7F,r7F7F,0x7f7f
|
|
cmplwi cr1,rN,0
|
|
beq L(unaligned)
|
|
|
|
mtctr rTMP
|
|
lwz rWORD1,0(rSTR1)
|
|
lwz rWORD2,0(rSTR2)
|
|
b L(g1)
|
|
|
|
L(g0):
|
|
lwzu rWORD1,4(rSTR1)
|
|
bne cr1,L(different)
|
|
lwzu rWORD2,4(rSTR2)
|
|
L(g1): add rTMP,rFEFE,rWORD1
|
|
nor rNEG,r7F7F,rWORD1
|
|
bdz L(tail)
|
|
and. rTMP,rTMP,rNEG
|
|
cmpw cr1,rWORD1,rWORD2
|
|
beq L(g0)
|
|
|
|
/* OK. We've hit the end of the string. We need to be careful that
|
|
we don't compare two strings as different because of gunk beyond
|
|
the end of the strings... */
|
|
|
|
L(endstring):
|
|
and rTMP,r7F7F,rWORD1
|
|
beq cr1,L(equal)
|
|
add rTMP,rTMP,r7F7F
|
|
xor. rBITDIF,rWORD1,rWORD2
|
|
|
|
andc rNEG,rNEG,rTMP
|
|
blt L(highbit)
|
|
cntlzw rBITDIF,rBITDIF
|
|
cntlzw rNEG,rNEG
|
|
addi rNEG,rNEG,7
|
|
cmpw cr1,rNEG,rBITDIF
|
|
sub rRTN,rWORD1,rWORD2
|
|
blt cr1,L(equal)
|
|
srawi rRTN,rRTN,31
|
|
ori rRTN,rRTN,1
|
|
blr
|
|
L(equal):
|
|
li rRTN,0
|
|
blr
|
|
|
|
L(different):
|
|
lwzu rWORD1,-4(rSTR1)
|
|
xor. rBITDIF,rWORD1,rWORD2
|
|
sub rRTN,rWORD1,rWORD2
|
|
blt L(highbit)
|
|
srawi rRTN,rRTN,31
|
|
ori rRTN,rRTN,1
|
|
blr
|
|
L(highbit):
|
|
srwi rWORD2,rWORD2,24
|
|
srwi rWORD1,rWORD1,24
|
|
sub rRTN,rWORD1,rWORD2
|
|
blr
|
|
|
|
|
|
/* Oh well. In this case, we just do a byte-by-byte comparison. */
|
|
.align 4
|
|
L(tail):
|
|
and. rTMP,rTMP,rNEG
|
|
cmpw cr1,rWORD1,rWORD2
|
|
bne L(endstring)
|
|
addi rSTR1,rSTR1,4
|
|
bne cr1,L(different)
|
|
addi rSTR2,rSTR2,4
|
|
cmplwi cr1,rN,0
|
|
L(unaligned):
|
|
mtctr rN
|
|
ble cr1,L(ux)
|
|
L(uz):
|
|
lbz rWORD1,0(rSTR1)
|
|
lbz rWORD2,0(rSTR2)
|
|
.align 4
|
|
L(u1):
|
|
cmpwi cr1,rWORD1,0
|
|
bdz L(u4)
|
|
cmpw rWORD1,rWORD2
|
|
beq cr1,L(u4)
|
|
bne L(u4)
|
|
lbzu rWORD3,1(rSTR1)
|
|
lbzu rWORD4,1(rSTR2)
|
|
cmpwi cr1,rWORD3,0
|
|
bdz L(u3)
|
|
cmpw rWORD3,rWORD4
|
|
beq cr1,L(u3)
|
|
bne L(u3)
|
|
lbzu rWORD1,1(rSTR1)
|
|
lbzu rWORD2,1(rSTR2)
|
|
cmpwi cr1,rWORD1,0
|
|
bdz L(u4)
|
|
cmpw rWORD1,rWORD2
|
|
beq cr1,L(u4)
|
|
bne L(u4)
|
|
lbzu rWORD3,1(rSTR1)
|
|
lbzu rWORD4,1(rSTR2)
|
|
cmpwi cr1,rWORD3,0
|
|
bdz L(u3)
|
|
cmpw rWORD3,rWORD4
|
|
beq cr1,L(u3)
|
|
bne L(u3)
|
|
lbzu rWORD1,1(rSTR1)
|
|
lbzu rWORD2,1(rSTR2)
|
|
b L(u1)
|
|
|
|
L(u3): sub rRTN,rWORD3,rWORD4
|
|
blr
|
|
L(u4): sub rRTN,rWORD1,rWORD2
|
|
blr
|
|
L(ux):
|
|
li rRTN,0
|
|
blr
|
|
END (strncmp)
|
|
libc_hidden_builtin_def (strncmp)
|