| /* Optimized strchr implementation for PowerPC64. |
| Copyright (C) 1997, 1999, 2000, 2002, 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 this works. */ |
| |
| /* char * [r3] strchr (const char *s [r3] , int c [r4] ) */ |
| |
| ENTRY (BP_SYM (strchr)) |
| CALL_MCOUNT 2 |
| |
| #define rTMP1 r0 |
| #define rRTN r3 /* outgoing result */ |
| /* Note: The Bounded pointer support in this code is broken. This code |
| was inherited from PPC32 and and that support was never completed. |
| Currently PPC gcc does not support -fbounds-check or -fbounded-pointers. |
| These artifacts are left in the code as a reminder in case we need |
| bounded pointer support in the future. */ |
| #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 0xfefefefefefefeff (-0x0101010101010101) */ |
| #define r7F7F r7 /* constant 0x7f7f7f7f7f7f7f7f */ |
| #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) |
| |
| dcbt 0,rRTN |
| rlwimi rCHR, rCHR, 8, 16, 23 |
| li rMASK, -1 |
| rlwimi rCHR, rCHR, 16, 0, 15 |
| rlwinm rIGN, rRTN, 3, 26, 28 |
| insrdi rCHR, rCHR, 32, 0 |
| lis rFEFE, -0x101 |
| lis r7F7F, 0x7f7f |
| clrrdi rSTR, rRTN, 3 |
| addi rFEFE, rFEFE, -0x101 |
| addi r7F7F, r7F7F, 0x7f7f |
| sldi rTMP1, rFEFE, 32 |
| insrdi r7F7F, r7F7F, 32, 0 |
| add rFEFE, rFEFE, rTMP1 |
| /* Test the first (partial?) word. */ |
| ld rWORD, 0(rSTR) |
| srd 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):ldu rWORD, 8(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 |
| cmpld rWORD, rTMP2 |
| bgtlr |
| cntlzd rCLZB, rTMP2 |
| srdi rCLZB, rCLZB, 3 |
| add rRTN, rSTR, rCLZB |
| CHECK_BOUNDS_HIGH_RTN (rSTR, rTMP2, tdlge) |
| STORE_RETURN_VALUE (rSTR) |
| blr |
| |
| L(foundit): |
| and rTMP1, r7F7F, rTMP3 |
| or rIGN, r7F7F, rTMP3 |
| add rTMP1, rTMP1, r7F7F |
| nor rTMP2, rIGN, rTMP1 |
| cntlzd rCLZB, rTMP2 |
| subi rSTR, rSTR, 8 |
| srdi rCLZB, rCLZB, 3 |
| add rRTN, rSTR, rCLZB |
| CHECK_BOUNDS_HIGH_RTN (rSTR, rTMP2, tdlge) |
| STORE_RETURN_VALUE (rSTR) |
| blr |
| END (BP_SYM (strchr)) |
| |
| weak_alias (BP_SYM (strchr), BP_SYM (index)) |
| libc_hidden_builtin_def (strchr) |
