mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-27 03:41:23 +08:00
181e000cfa
1999-06-22 Geoff Keating <geoffk@ozemail.com.au> * sysdeps/powerpc/strcmp.S: Don't return a zero result if the high bits of two words differ.
116 lines
2.7 KiB
ArmAsm
116 lines
2.7 KiB
ArmAsm
/* Optimized strcmp implementation for PowerPC.
|
|
Copyright (C) 1997 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 Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#include <sysdep.h>
|
|
|
|
/* See strlen.s for comments on how the end-of-string testing works. */
|
|
|
|
EALIGN(strcmp,4,0)
|
|
/* int [r3] strcmp (const char *p1 [r3], const char *p2 [r4]) */
|
|
|
|
/* General register assignments:
|
|
r0: temporary
|
|
r3: pointer to previous word in s1
|
|
r4: pointer to previous word in s2
|
|
r5: current word from s1
|
|
r6: current word from s2
|
|
r7: 0xfefefeff
|
|
r8: 0x7f7f7f7f
|
|
r9: ~(word in s1 | 0x7f7f7f7f) */
|
|
|
|
/* Register assignments in the prologue:
|
|
r10: low 2 bits of p2-p1
|
|
r11: mask to orc with r5/r6 */
|
|
|
|
or %r0,%r4,%r3
|
|
clrlwi. %r0,%r0,30
|
|
lis %r7,0xfeff
|
|
bne L(unaligned)
|
|
|
|
lwz %r5,0(%r3)
|
|
lwz %r6,0(%r4)
|
|
lis %r8,0x7f7f
|
|
addi %r7,%r7,-0x101
|
|
addi %r8,%r8,0x7f7f
|
|
b 1f
|
|
|
|
0: lwzu %r5,4(%r3)
|
|
bne %cr1,L(different)
|
|
lwzu %r6,4(%r4)
|
|
1: add %r0,%r7,%r5
|
|
nor %r9,%r8,%r5
|
|
and. %r0,%r0,%r9
|
|
cmpw %cr1,%r5,%r6
|
|
beq+ 0b
|
|
L(endstring):
|
|
/* 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... */
|
|
and %r0,%r8,%r5
|
|
beq %cr1,L(equal)
|
|
add %r0,%r0,%r8
|
|
xor. %r10,%r5,%r6
|
|
andc %r9,%r9,%r0
|
|
blt- L(highbit)
|
|
cntlzw %r10,%r10
|
|
cntlzw %r9,%r9
|
|
addi %r9,%r9,7
|
|
cmpw %cr1,%r9,%r10
|
|
sub %r3,%r5,%r6
|
|
bgelr+ %cr1
|
|
L(equal):
|
|
li %r3,0
|
|
blr
|
|
|
|
L(different):
|
|
lwz %r5,-4(%r3)
|
|
xor. %r10,%r5,%r6
|
|
sub %r3,%r5,%r6
|
|
bgelr+
|
|
L(highbit):
|
|
ori %r3,%r6,1
|
|
blr
|
|
|
|
|
|
/* Oh well. In this case, we just do a byte-by-byte comparison. */
|
|
.align 4
|
|
L(unaligned):
|
|
lbz %r5,0(%r3)
|
|
lbz %r6,0(%r4)
|
|
b 1f
|
|
|
|
0: lbzu %r5,1(%r3)
|
|
bne- 4f
|
|
lbzu %r6,1(%r4)
|
|
1: cmpwi %cr1,%r5,0
|
|
beq- %cr1,3f
|
|
cmpw %r5,%r6
|
|
bne- 3f
|
|
lbzu %r5,1(%r3)
|
|
lbzu %r6,1(%r4)
|
|
cmpwi %cr1,%r5,0
|
|
cmpw %r5,%r6
|
|
bne+ %cr1,0b
|
|
3: sub %r3,%r5,%r6
|
|
blr
|
|
4: lbz %r5,-1(%r3)
|
|
sub %r3,%r5,%r6
|
|
blr
|
|
END(strcmp)
|