projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| a72cc2b2 | 1 | /* Optimized strlen implementation for PowerPC476. |
| 04277e02 | 2 | Copyright (C) 2010-2019 Free Software Foundation, Inc. |
| a72cc2b2 LM |
3 | This file is part of the GNU C Library. |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 6 | modify it under the terms of the GNU Lesser General Public | |
| 7 | License as published by the Free Software Foundation; either | |
| 8 | version 2.1 of the License, or (at your option) any later version. | |
| 9 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | Lesser General Public License for more details. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | |
| ab84e3ff | 16 | License along with the GNU C Library. If not, see |
| 5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
| a72cc2b2 LM |
18 | |
| 19 | #include <sysdep.h> | |
| a72cc2b2 LM |
20 | |
| 21 | /* strlen | |
| 22 | ||
| 23 | Register Use | |
| 24 | r3:source address and return length of string | |
| 25 | r4:byte counter | |
| 26 | ||
| 27 | Implementation description | |
| 28 | Load 2 words at a time and count bytes, if we find null we subtract one from | |
| 29 | the count and return the count value. We need to subtract one because | |
| 30 | we don't count the null character as a byte. */ | |
| 31 | ||
| b5510883 | 32 | EALIGN (strlen,5,0) |
| a72cc2b2 LM |
33 | neg r7,r3 |
| 34 | clrlwi. r8,r7,29 | |
| 35 | addi r4,0,0 | |
| 36 | beq L(byte_count_loop) | |
| 37 | mtctr r8 | |
| 38 | ||
| 39 | L(loop): | |
| 40 | lbz r5,0(r3) | |
| 41 | cmpi cr5,r5,0x0 | |
| 42 | addi r3,r3,0x1 | |
| 43 | addi r4,r4,0x1 | |
| 44 | beq cr5,L(end_strlen) | |
| 45 | bdnz L(loop) | |
| 46 | ||
| 47 | L(byte_count_loop): | |
| 48 | lwz r5,0(r3) | |
| 49 | lwz r6,4(r3) | |
| 50 | dlmzb. r12,r5,r6 | |
| 51 | add r4,r4,r12 | |
| 52 | bne L(end_strlen) | |
| 53 | lwz r5,8(r3) | |
| 54 | lwz r6,12(r3) | |
| 55 | dlmzb. r12,r5,r6 | |
| 56 | add r4,r4,r12 | |
| 57 | bne L(end_strlen) | |
| 58 | lwz r5,16(r3) | |
| 59 | lwz r6,20(r3) | |
| 60 | dlmzb. r12,r5,r6 | |
| 61 | add r4,r4,r12 | |
| 62 | bne L(end_strlen) | |
| 63 | lwz r5,24(r3) | |
| 64 | lwz r6,28(r3) | |
| 65 | addi r3,r3,0x20 | |
| 66 | dlmzb. r12,r5,r6 | |
| 67 | add r4,r4,r12 | |
| 68 | bne L(end_strlen) | |
| 69 | b L(byte_count_loop) | |
| 70 | ||
| 71 | L(end_strlen): | |
| 72 | addi r3,r4,-1 | |
| 73 | blr | |
| b5510883 | 74 | END (strlen) |
| a72cc2b2 | 75 | libc_hidden_builtin_def (strlen) |