diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/strncmp.S | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/strncmp.S b/sysdeps/powerpc/powerpc32/strncmp.S new file mode 100644 index 0000000000..3b33bb921f --- /dev/null +++ b/sysdeps/powerpc/powerpc32/strncmp.S @@ -0,0 +1,156 @@ +/* Optimized strcmp implementation for PowerPC32. + Copyright (C) 2003 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] 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 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 + 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 + beq L(unaligned) + + mtctr rTMP /* Power4 wants mtctr 1st in dispatch group. */ + 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 +L(unaligned): + mtctr rN /* Power4 wants mtctr 1st in dispatch group */ + cmpwi rN,0 + lbz rWORD1, 0(rSTR1) + lbz rWORD2, 0(rSTR2) + bgt L(u1) +L(ux): + li rRTN, 0 + blr + +L(u0): + lbzu rWORD2, 1(rSTR2) +L(u1): + bdz L(u3) + cmpwi cr1, rWORD1, 0 + cmpw rWORD1, rWORD2 + beq- cr1, L(u3) + lbzu rWORD1, 1(rSTR1) + bne- L(u2) + lbzu rWORD2, 1(rSTR2) + bdz L(u3) + cmpwi cr1, rWORD1, 0 + cmpw rWORD1, rWORD2 + bne- L(u3) + lbzu rWORD1, 1(rSTR1) + bne+ cr1, L(u0) + +L(u2): lbzu rWORD1, -1(rSTR1) +L(u3): sub rRTN, rWORD1, rWORD2 + blr +END (BP_SYM (strncmp)) +libc_hidden_builtin_def (strncmp) |