mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 01:00:07 +00:00
177 lines
4.6 KiB
ArmAsm
177 lines
4.6 KiB
ArmAsm
/* Optimized strcmp implementation for PowerPC64.
|
|
Copyright (C) 1997-2014 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] strcmp (const char *s1 [r3], const char *s2 [r4]) */
|
|
|
|
EALIGN (strcmp, 4, 0)
|
|
CALL_MCOUNT 2
|
|
|
|
#define rTMP2 r0
|
|
#define rRTN r3
|
|
#define rSTR1 r3 /* first string arg */
|
|
#define rSTR2 r4 /* second string arg */
|
|
#define rWORD1 r5 /* current word in s1 */
|
|
#define rWORD2 r6 /* current word in s2 */
|
|
#define rFEFE r7 /* constant 0xfefefefefefefeff (-0x0101010101010101) */
|
|
#define r7F7F r8 /* constant 0x7f7f7f7f7f7f7f7f */
|
|
#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */
|
|
#define rBITDIF r10 /* bits that differ in s1 & s2 words */
|
|
#define rTMP r11
|
|
|
|
dcbt 0,rSTR1
|
|
or rTMP, rSTR2, rSTR1
|
|
dcbt 0,rSTR2
|
|
clrldi. rTMP, rTMP, 61
|
|
lis rFEFE, -0x101
|
|
bne L(unaligned)
|
|
|
|
ld rWORD1, 0(rSTR1)
|
|
ld rWORD2, 0(rSTR2)
|
|
lis r7F7F, 0x7f7f
|
|
addi rFEFE, rFEFE, -0x101
|
|
addi r7F7F, r7F7F, 0x7f7f
|
|
sldi rTMP, rFEFE, 32
|
|
insrdi r7F7F, r7F7F, 32, 0
|
|
add rFEFE, rFEFE, rTMP
|
|
b L(g1)
|
|
|
|
L(g0): ldu rWORD1, 8(rSTR1)
|
|
bne cr1, L(different)
|
|
ldu rWORD2, 8(rSTR2)
|
|
L(g1): add rTMP, rFEFE, rWORD1
|
|
nor rNEG, r7F7F, rWORD1
|
|
and. rTMP, rTMP, rNEG
|
|
cmpd 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... */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
L(endstring):
|
|
addi rTMP2, rTMP, -1
|
|
beq cr1, L(equal)
|
|
andc rTMP2, rTMP2, rTMP
|
|
rldimi rTMP2, rTMP2, 1, 0
|
|
and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
|
|
and rWORD1, rWORD1, rTMP2
|
|
cmpd cr1, rWORD1, rWORD2
|
|
beq cr1, L(equal)
|
|
xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */
|
|
neg rNEG, rBITDIF
|
|
and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */
|
|
cntlzd rNEG, rNEG /* bitcount of the bit. */
|
|
andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */
|
|
sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */
|
|
sld rWORD2, rWORD2, rNEG
|
|
xor. rBITDIF, rWORD1, rWORD2
|
|
sub rRTN, rWORD1, rWORD2
|
|
blt- L(highbit)
|
|
sradi rRTN, rRTN, 63 /* must return an int. */
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
L(equal):
|
|
li rRTN, 0
|
|
blr
|
|
|
|
L(different):
|
|
ld rWORD1, -8(rSTR1)
|
|
xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */
|
|
neg rNEG, rBITDIF
|
|
and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */
|
|
cntlzd rNEG, rNEG /* bitcount of the bit. */
|
|
andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */
|
|
sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */
|
|
sld rWORD2, rWORD2, rNEG
|
|
xor. rBITDIF, rWORD1, rWORD2
|
|
sub rRTN, rWORD1, rWORD2
|
|
blt- L(highbit)
|
|
sradi rRTN, rRTN, 63
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
L(highbit):
|
|
sradi rRTN, rWORD2, 63
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
|
|
#else
|
|
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)
|
|
cntlzd rBITDIF, rBITDIF
|
|
cntlzd rNEG, rNEG
|
|
addi rNEG, rNEG, 7
|
|
cmpd cr1, rNEG, rBITDIF
|
|
sub rRTN, rWORD1, rWORD2
|
|
blt- cr1, L(equal)
|
|
sradi rRTN, rRTN, 63 /* must return an int. */
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
L(equal):
|
|
li rRTN, 0
|
|
blr
|
|
|
|
L(different):
|
|
ld rWORD1, -8(rSTR1)
|
|
xor. rBITDIF, rWORD1, rWORD2
|
|
sub rRTN, rWORD1, rWORD2
|
|
blt- L(highbit)
|
|
sradi rRTN, rRTN, 63
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
L(highbit):
|
|
sradi rRTN, rWORD2, 63
|
|
ori rRTN, rRTN, 1
|
|
blr
|
|
#endif
|
|
|
|
/* Oh well. In this case, we just do a byte-by-byte comparison. */
|
|
.align 4
|
|
L(unaligned):
|
|
lbz rWORD1, 0(rSTR1)
|
|
lbz rWORD2, 0(rSTR2)
|
|
b L(u1)
|
|
|
|
L(u0): lbzu rWORD1, 1(rSTR1)
|
|
bne- L(u4)
|
|
lbzu rWORD2, 1(rSTR2)
|
|
L(u1): cmpwi cr1, rWORD1, 0
|
|
beq- cr1, L(u3)
|
|
cmpd rWORD1, rWORD2
|
|
bne- L(u3)
|
|
lbzu rWORD1, 1(rSTR1)
|
|
lbzu rWORD2, 1(rSTR2)
|
|
cmpdi cr1, rWORD1, 0
|
|
cmpd rWORD1, rWORD2
|
|
bne+ cr1, L(u0)
|
|
L(u3): sub rRTN, rWORD1, rWORD2
|
|
blr
|
|
L(u4): lbz rWORD1, -1(rSTR1)
|
|
sub rRTN, rWORD1, rWORD2
|
|
blr
|
|
END (strcmp)
|
|
libc_hidden_builtin_def (strcmp)
|