diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/strchr.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/strchr.S | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/strchr.S b/sysdeps/powerpc/powerpc32/strchr.S new file mode 100644 index 0000000000..1adee411b6 --- /dev/null +++ b/sysdeps/powerpc/powerpc32/strchr.S @@ -0,0 +1,130 @@ +/* Optimized strchr 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 this works. */ + +/* char * [r3] strchr (const char *s [r3] , int c [r4] ) */ + +ENTRY (BP_SYM (strchr)) + +#define rTMP1 r0 +#define rRTN r3 /* outgoing result */ +#if __BOUNDED_POINTERS__ +# define rSTR r4 +# define rCHR r5 /* byte we're looking for, spread over the whole word */ +# define rWORD r8 /* the current word */ +#else +# define rSTR r8 /* current word pointer */ +# define rCHR r4 /* byte we're looking for, spread over the whole word */ +# define rWORD r5 /* the current word */ +#endif +#define rCLZB rCHR /* leading zero byte count */ +#define rFEFE r6 /* constant 0xfefefeff (-0x01010101) */ +#define r7F7F r7 /* constant 0x7f7f7f7f */ +#define rTMP2 r9 +#define rIGN r10 /* number of bits we should ignore in the first word */ +#define rMASK r11 /* mask with the bits to ignore set to 0 */ +#define rTMP3 r12 + + CHECK_BOUNDS_LOW (rSTR, rTMP1, rTMP2) + STORE_RETURN_BOUNDS (rTMP1, rTMP2) + + rlwimi rCHR, rCHR, 8, 16, 23 + li rMASK, -1 + rlwimi rCHR, rCHR, 16, 0, 15 + rlwinm rIGN, rRTN, 3, 27, 28 + lis rFEFE, -0x101 + lis r7F7F, 0x7f7f + clrrwi rSTR, rRTN, 2 + addi rFEFE, rFEFE, -0x101 + addi r7F7F, r7F7F, 0x7f7f +/* Test the first (partial?) word. */ + lwz rWORD, 0(rSTR) + srw rMASK, rMASK, rIGN + orc rWORD, rWORD, rMASK + add rTMP1, rFEFE, rWORD + nor rTMP2, r7F7F, rWORD + and. rTMP1, rTMP1, rTMP2 + xor rTMP3, rCHR, rWORD + orc rTMP3, rTMP3, rMASK + b L(loopentry) + +/* The loop. */ + +L(loop):lwzu rWORD, 4(rSTR) + and. rTMP1, rTMP1, rTMP2 +/* Test for 0. */ + add rTMP1, rFEFE, rWORD + nor rTMP2, r7F7F, rWORD + bne L(foundit) + and. rTMP1, rTMP1, rTMP2 +/* Start test for the bytes we're looking for. */ + xor rTMP3, rCHR, rWORD +L(loopentry): + add rTMP1, rFEFE, rTMP3 + nor rTMP2, r7F7F, rTMP3 + beq L(loop) +/* There is a zero byte in the word, but may also be a matching byte (either + before or after the zero byte). In fact, we may be looking for a + zero byte, in which case we return a match. We guess that this hasn't + happened, though. */ +L(missed): + and. rTMP1, rTMP1, rTMP2 + li rRTN, 0 + STORE_RETURN_VALUE (rSTR) + beqlr +/* It did happen. Decide which one was first... + I'm not sure if this is actually faster than a sequence of + rotates, compares, and branches (we use it anyway because it's shorter). */ + and rFEFE, r7F7F, rWORD + or rMASK, r7F7F, rWORD + and rTMP1, r7F7F, rTMP3 + or rIGN, r7F7F, rTMP3 + add rFEFE, rFEFE, r7F7F + add rTMP1, rTMP1, r7F7F + nor rWORD, rMASK, rFEFE + nor rTMP2, rIGN, rTMP1 + cmplw rWORD, rTMP2 + bgtlr + cntlzw rCLZB, rTMP2 + srwi rCLZB, rCLZB, 3 + add rRTN, rSTR, rCLZB + CHECK_BOUNDS_HIGH_RTN (rSTR, rTMP2, twlge) + STORE_RETURN_VALUE (rSTR) + blr + +L(foundit): + and rTMP1, r7F7F, rTMP3 + or rIGN, r7F7F, rTMP3 + add rTMP1, rTMP1, r7F7F + nor rTMP2, rIGN, rTMP1 + cntlzw rCLZB, rTMP2 + subi rSTR, rSTR, 4 + srwi rCLZB, rCLZB, 3 + add rRTN, rSTR, rCLZB + CHECK_BOUNDS_HIGH_RTN (rSTR, rTMP2, twlge) + STORE_RETURN_VALUE (rSTR) + blr +END (BP_SYM (strchr)) + +weak_alias (BP_SYM (strchr), BP_SYM (index)) |