diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/power7/strncmp.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/power7/strncmp.S | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/power7/strncmp.S b/sysdeps/powerpc/powerpc32/power7/strncmp.S new file mode 100644 index 0000000000..ba72d0a029 --- /dev/null +++ b/sysdeps/powerpc/powerpc32/power7/strncmp.S @@ -0,0 +1,177 @@ +/* Optimized strcmp implementation for POWER7/PowerPC32. + Copyright (C) 2010 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., 51 Franklin Street, Fifth Floor, Boston MA + 02110-1301 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] 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 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 rWORD3 r10 +#define rWORD4 r11 +#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 + 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 + ble cr1,L(ux) +L(uz): + lbz rWORD1,0(rSTR1) + lbz rWORD2,0(rSTR2) + .align 4 +L(u1): + cmpwi cr1,rWORD1,0 + bdz L(u4) + cmpw rWORD1,rWORD2 + beq cr1,L(u4) + lbzu rWORD3,1(rSTR1) + lbzu rWORD4,1(rSTR2) + bne L(u4) + cmpwi cr1,rWORD3,0 + bdz L(u3) + cmpw rWORD3,rWORD4 + beq cr1,L(u3) + lbzu rWORD1,1(rSTR1) + lbzu rWORD2,1(rSTR2) + bne L(u3) + cmpwi cr1,rWORD1,0 + bdz L(u4) + cmpw rWORD1,rWORD2 + beq cr1,L(u4) + lbzu rWORD3,1(rSTR1) + lbzu rWORD4,1(rSTR2) + bne L(u4) + cmpwi cr1,rWORD3,0 + bdz L(u3) + cmpw rWORD3,rWORD4 + beq cr1,L(u3) + lbzu rWORD1,1(rSTR1) + lbzu rWORD2,1(rSTR2) + beq L(u1) + +L(u3): sub rRTN,rWORD3,rWORD4 + blr +L(u4): sub rRTN,rWORD1,rWORD2 + blr +L(ux): + li rRTN,0 + blr +END (BP_SYM (strncmp)) +libc_hidden_builtin_def (strncmp) |