projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 04277e02 | 1 | /* Copyright (C) 1998-2019 Free Software Foundation, Inc. |
| 42d5b281 UD |
2 | This file is part of the GNU C Library. |
| 3 | Code contributed by Matthew Wilcox <willy@odie.barnet.ac.uk> | |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 3214b89b AJ |
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. | |
| 42d5b281 UD |
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 | |
| 3214b89b | 13 | Lesser General Public License for more details. |
| 42d5b281 | 14 | |
| 3214b89b | 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/>. */ |
| 42d5b281 | 18 | |
| 365261c3 RH |
19 | /* Thumb requires excessive IT insns here. */ |
| 20 | #define NO_THUMB | |
| 42d5b281 UD |
21 | #include <sysdep.h> |
| 22 | ||
| 23 | /* size_t strlen(const char *S) | |
| 24 | * entry: r0 -> string | |
| 25 | * exit: r0 = len | |
| 26 | */ | |
| 27 | ||
| 38435a9a RM |
28 | .syntax unified |
| 29 | .text | |
| 30 | ||
| 42d5b281 UD |
31 | ENTRY(strlen) |
| 32 | bic r1, r0, $3 @ addr of word containing first byte | |
| 81cb7a0b | 33 | ldr r2, [r1], $4 @ get the first word |
| 42d5b281 UD |
34 | ands r3, r0, $3 @ how many bytes are duff? |
| 35 | rsb r0, r3, $0 @ get - that number into counter. | |
| 36 | beq Laligned @ skip into main check routine if no | |
| 37 | @ more | |
| 69069c4a | 38 | #ifdef __ARMEB__ |
| 42d5b281 UD |
39 | orr r2, r2, $0xff000000 @ set this byte to non-zero |
| 40 | subs r3, r3, $1 @ any more to do? | |
| 41 | orrgt r2, r2, $0x00ff0000 @ if so, set this byte | |
| 42 | subs r3, r3, $1 @ more? | |
| 43 | orrgt r2, r2, $0x0000ff00 @ then set. | |
| 69069c4a UD |
44 | #else |
| 45 | orr r2, r2, $0x000000ff @ set this byte to non-zero | |
| 46 | subs r3, r3, $1 @ any more to do? | |
| 47 | orrgt r2, r2, $0x0000ff00 @ if so, set this byte | |
| 48 | subs r3, r3, $1 @ more? | |
| 49 | orrgt r2, r2, $0x00ff0000 @ then set. | |
| 50 | #endif | |
| 42d5b281 UD |
51 | Laligned: @ here, we have a word in r2. Does it |
| 52 | tst r2, $0x000000ff @ contain any zeroes? | |
| 53 | tstne r2, $0x0000ff00 @ | |
| 54 | tstne r2, $0x00ff0000 @ | |
| 55 | tstne r2, $0xff000000 @ | |
| 56 | addne r0, r0, $4 @ if not, the string is 4 bytes longer | |
| 81cb7a0b | 57 | ldrne r2, [r1], $4 @ and we continue to the next word |
| 42d5b281 UD |
58 | bne Laligned @ |
| 59 | Llastword: @ drop through to here once we find a | |
| 482f8700 RM |
60 | #ifdef __ARMEB__ |
| 61 | tst r2, $0xff000000 @ word that has a zero byte in it | |
| 62 | addne r0, r0, $1 @ | |
| 63 | tstne r2, $0x00ff0000 @ and add up to 3 bytes on to it | |
| 64 | addne r0, r0, $1 @ | |
| 65 | tstne r2, $0x0000ff00 @ (if first three all non-zero, 4th | |
| 66 | addne r0, r0, $1 @ must be zero) | |
| 67 | #else | |
| 42d5b281 UD |
68 | tst r2, $0x000000ff @ word that has a zero byte in it |
| 69 | addne r0, r0, $1 @ | |
| 70 | tstne r2, $0x0000ff00 @ and add up to 3 bytes on to it | |
| 71 | addne r0, r0, $1 @ | |
| 72 | tstne r2, $0x00ff0000 @ (if first three all non-zero, 4th | |
| 73 | addne r0, r0, $1 @ must be zero) | |
| 482f8700 | 74 | #endif |
| 47f0752a | 75 | DO_RET(lr) |
| 42d5b281 | 76 | END(strlen) |
| 79b7c863 | 77 | libc_hidden_builtin_def (strlen) |