diff options
Diffstat (limited to 'sysdeps/powerpc/strcmp.S')
-rw-r--r-- | sysdeps/powerpc/strcmp.S | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/sysdeps/powerpc/strcmp.S b/sysdeps/powerpc/strcmp.S new file mode 100644 index 0000000000..9f4d134419 --- /dev/null +++ b/sysdeps/powerpc/strcmp.S @@ -0,0 +1,115 @@ +/* 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): + mr %r3,%r6 + 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) |