diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/strcmp.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/strcmp.S | 126 |
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 0000000..2c96b57 --- /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)) |