summaryrefslogtreecommitdiff
path: root/sysdeps/powerpc/strcmp.S
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/powerpc/strcmp.S')
-rw-r--r--sysdeps/powerpc/strcmp.S115
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)