aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/powerpc/powerpc32/strcmp.S
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/powerpc/powerpc32/strcmp.S')
-rw-r--r--sysdeps/powerpc/powerpc32/strcmp.S126
1 files changed, 126 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/strcmp.S b/sysdeps/powerpc/powerpc32/strcmp.S
new file mode 100644
index 0000000000..2c96b57016
--- /dev/null
+++ b/sysdeps/powerpc/powerpc32/strcmp.S
@@ -0,0 +1,126 @@
+/* Optimized strcmp implementation for PowerPC.
+ Copyright (C) 1997, 1999, 2000 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#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] strcmp (const char *s1 [r3], const char *s2 [r4]) */
+
+EALIGN (BP_SYM (strcmp), 4, 0)
+
+#define rTMP r0
+#define rRTN r3
+#define rSTR1 r3 /* first string arg */
+#define rSTR2 r4 /* second string arg */
+#if __BOUNDED_POINTERS__
+# define rHIGH1 r11
+# define rHIGH2 r12
+#endif
+#define rWORD1 r5 /* current word in s1 */
+#define rWORD2 r6 /* current word in s2 */
+#define rFEFE r7 /* constant 0xfefefeff (-0x01010101) */
+#define r7F7F r8 /* constant 0x7f7f7f7f */
+#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f) */
+#define rBITDIF r10 /* bits that differ in s1 & s2 words */
+
+ CHECK_BOUNDS_LOW (rSTR1, rTMP, rHIGH1)
+ CHECK_BOUNDS_LOW (rSTR2, rTMP, rHIGH2)
+
+ or rTMP, rSTR2, rSTR1
+ clrlwi. rTMP, rTMP, 30
+ lis rFEFE, -0x101
+ bne L(unaligned)
+
+ lwz rWORD1, 0(rSTR1)
+ lwz rWORD2, 0(rSTR2)
+ lis r7F7F, 0x7f7f
+ addi rFEFE, rFEFE, -0x101
+ addi r7F7F, r7F7F, 0x7f7f
+ 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
+ and. rTMP, rTMP, rNEG
+ cmpw cr1, rWORD1, rWORD2
+ beq+ L(g0)
+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 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
+ bgelr+ cr1
+L(equal):
+ li rRTN, 0
+ /* GKM FIXME: check high bounds. */
+ blr
+
+L(different):
+ lwz rWORD1, -4(rSTR1)
+ xor. rBITDIF, rWORD1, rWORD2
+ sub rRTN, rWORD1, rWORD2
+ bgelr+
+L(highbit):
+ ori rRTN, rWORD2, 1
+ /* GKM FIXME: check high bounds. */
+ blr
+
+
+/* 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)
+ cmpw rWORD1, rWORD2
+ bne- L(u3)
+ lbzu rWORD1, 1(rSTR1)
+ lbzu rWORD2, 1(rSTR2)
+ cmpwi cr1, rWORD1, 0
+ cmpw rWORD1, rWORD2
+ bne+ cr1, L(u0)
+L(u3): sub rRTN, rWORD1, rWORD2
+ /* GKM FIXME: check high bounds. */
+ blr
+L(u4): lbz rWORD1, -1(rSTR1)
+ sub rRTN, rWORD1, rWORD2
+ /* GKM FIXME: check high bounds. */
+ blr
+END (BP_SYM (strcmp))