mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
161 lines
4.0 KiB
ArmAsm
161 lines
4.0 KiB
ArmAsm
/* Optimized strcmp implementation for PowerPC32.
|
|
Copyright (C) 2003, 2011 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>
|
|
#include <bp-sym.h>
|
|
#include <bp-asm.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 (BP_SYM(strncmp), 4, 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 */
|
|
/* Note: The Bounded pointer support in this code is broken. This code
|
|
was inherited from PPC32 and that support was never completed.
|
|
Current PPC gcc does not support -fbounds-check or -fbounded-pointers. */
|
|
#define rWORD1 r6 /* current word in s1 */
|
|
#define rWORD2 r7 /* current word in s2 */
|
|
#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
|
|
or rTMP, rSTR2, rSTR1
|
|
lis r7F7F, 0x7f7f
|
|
dcbt 0,rSTR2
|
|
clrlwi. rTMP, rTMP, 30
|
|
cmplwi cr1, rN, 0
|
|
lis rFEFE, -0x101
|
|
bne L(unaligned)
|
|
/* We are word alligned 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 /* Power4 wants mtctr 1st in dispatch group. */
|
|
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 /* Power4 wants mtctr 1st in dispatch group */
|
|
bgt cr1, L(uz)
|
|
L(ux):
|
|
li rRTN, 0
|
|
blr
|
|
.align 4
|
|
L(uz):
|
|
lbz rWORD1, 0(rSTR1)
|
|
lbz rWORD2, 0(rSTR2)
|
|
nop
|
|
b L(u1)
|
|
L(u0):
|
|
lbzu rWORD2, 1(rSTR2)
|
|
L(u1):
|
|
bdz L(u3)
|
|
cmpwi cr1, rWORD1, 0
|
|
cmpw rWORD1, rWORD2
|
|
beq- cr1, L(u3)
|
|
lbzu rWORD1, 1(rSTR1)
|
|
bne- L(u2)
|
|
lbzu rWORD2, 1(rSTR2)
|
|
bdz L(u3)
|
|
cmpwi cr1, rWORD1, 0
|
|
cmpw rWORD1, rWORD2
|
|
bne- L(u3)
|
|
lbzu rWORD1, 1(rSTR1)
|
|
bne+ cr1, L(u0)
|
|
|
|
L(u2): lbzu rWORD1, -1(rSTR1)
|
|
L(u3): sub rRTN, rWORD1, rWORD2
|
|
blr
|
|
END (BP_SYM (strncmp))
|
|
libc_hidden_builtin_def (strncmp)
|