projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 2601bc18 WN |
1 | /* Copyright (C) 2010-2011,2013 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. | |
| 3 | ||
| 4 | The GNU C Library is free software; you can redistribute it and/or | |
| 5 | modify it under the terms of the GNU Lesser General Public | |
| 6 | License as published by the Free Software Foundation; either | |
| 7 | version 2.1 of the License, or (at your option) any later version. | |
| 8 | ||
| 9 | The GNU C Library is distributed in the hope that it will be useful, | |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 12 | Lesser General Public License for more details. | |
| 13 | ||
| 14 | You should have received a copy of the GNU Lesser General Public | |
| 15 | License along with the GNU C Library. If not, see | |
| 16 | <http://www.gnu.org/licenses/>. */ | |
| 17 | ||
| 18 | /* | |
| 19 | Assumes: | |
| 20 | ARMv6T2, AArch32 | |
| 21 | ||
| 22 | */ | |
| 23 | ||
| 21bfcecf | 24 | #include <arm-features.h> /* This might #define NO_THUMB. */ |
| 2601bc18 WN |
25 | #include <sysdep.h> |
| 26 | ||
| 27 | #ifdef __ARMEB__ | |
| 28 | #define S2LO lsl | |
| 29 | #define S2HI lsr | |
| 30 | #else | |
| 31 | #define S2LO lsr | |
| 32 | #define S2HI lsl | |
| 33 | #endif | |
| 34 | ||
| 21bfcecf RM |
35 | #ifndef NO_THUMB |
| 36 | /* This code is best on Thumb. */ | |
| 2601bc18 | 37 | .thumb |
| 21bfcecf RM |
38 | #else |
| 39 | /* Using bne.w explicitly is desirable in Thumb mode because it helps | |
| 40 | align the following label without a nop. In ARM mode there is no | |
| 41 | such difference. */ | |
| 42 | .macro bne.w label | |
| 43 | bne \label | |
| 44 | .endm | |
| 45 | ||
| 46 | /* This clobbers the condition codes, which the real Thumb cbnz instruction | |
| 47 | does not do. But it doesn't matter for any of the uses here. */ | |
| 48 | .macro cbnz reg, label | |
| 49 | cmp \reg, #0 | |
| 50 | bne \label | |
| 51 | .endm | |
| 52 | #endif | |
| 2601bc18 WN |
53 | |
| 54 | /* Parameters and result. */ | |
| 55 | #define srcin r0 | |
| 56 | #define result r0 | |
| 57 | ||
| 58 | /* Internal variables. */ | |
| 59 | #define src r1 | |
| 60 | #define data1a r2 | |
| 61 | #define data1b r3 | |
| 62 | #define const_m1 r12 | |
| 63 | #define const_0 r4 | |
| 64 | #define tmp1 r4 /* Overlaps const_0 */ | |
| 65 | #define tmp2 r5 | |
| 66 | ||
| 67 | .text | |
| 68 | .p2align 6 | |
| 69 | ENTRY(strlen) | |
| 70 | pld [srcin, #0] | |
| 71 | strd r4, r5, [sp, #-8]! | |
| 72 | cfi_adjust_cfa_offset (8) | |
| 73 | cfi_rel_offset (r4, 0) | |
| 74 | cfi_rel_offset (r5, 4) | |
| 75 | cfi_remember_state | |
| 76 | bic src, srcin, #7 | |
| 77 | mvn const_m1, #0 | |
| 78 | ands tmp1, srcin, #7 /* (8 - bytes) to alignment. */ | |
| 79 | pld [src, #32] | |
| 80 | bne.w .Lmisaligned8 | |
| 81 | mov const_0, #0 | |
| 82 | mov result, #-8 | |
| 83 | .Lloop_aligned: | |
| 84 | /* Bytes 0-7. */ | |
| 85 | ldrd data1a, data1b, [src] | |
| 86 | pld [src, #64] | |
| 87 | add result, result, #8 | |
| 88 | .Lstart_realigned: | |
| 89 | uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */ | |
| 90 | sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */ | |
| 91 | uadd8 data1b, data1b, const_m1 | |
| 92 | sel data1b, data1a, const_m1 /* Only used if d1a == 0. */ | |
| 93 | cbnz data1b, .Lnull_found | |
| 94 | ||
| 95 | /* Bytes 8-15. */ | |
| 96 | ldrd data1a, data1b, [src, #8] | |
| 97 | uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */ | |
| 98 | add result, result, #8 | |
| 99 | sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */ | |
| 100 | uadd8 data1b, data1b, const_m1 | |
| 101 | sel data1b, data1a, const_m1 /* Only used if d1a == 0. */ | |
| 102 | cbnz data1b, .Lnull_found | |
| 103 | ||
| 104 | /* Bytes 16-23. */ | |
| 105 | ldrd data1a, data1b, [src, #16] | |
| 106 | uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */ | |
| 107 | add result, result, #8 | |
| 108 | sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */ | |
| 109 | uadd8 data1b, data1b, const_m1 | |
| 110 | sel data1b, data1a, const_m1 /* Only used if d1a == 0. */ | |
| 111 | cbnz data1b, .Lnull_found | |
| 112 | ||
| 113 | /* Bytes 24-31. */ | |
| 114 | ldrd data1a, data1b, [src, #24] | |
| 115 | add src, src, #32 | |
| 116 | uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */ | |
| 117 | add result, result, #8 | |
| 118 | sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */ | |
| 119 | uadd8 data1b, data1b, const_m1 | |
| 120 | sel data1b, data1a, const_m1 /* Only used if d1a == 0. */ | |
| 121 | cmp data1b, #0 | |
| 122 | beq .Lloop_aligned | |
| 123 | ||
| 124 | .Lnull_found: | |
| 125 | cmp data1a, #0 | |
| 126 | itt eq | |
| 127 | addeq result, result, #4 | |
| 128 | moveq data1a, data1b | |
| 129 | #ifndef __ARMEB__ | |
| 130 | rev data1a, data1a | |
| 131 | #endif | |
| 132 | clz data1a, data1a | |
| 133 | ldrd r4, r5, [sp], #8 | |
| 134 | cfi_adjust_cfa_offset (-8) | |
| 135 | cfi_restore (r4) | |
| 136 | cfi_restore (r5) | |
| 137 | add result, result, data1a, lsr #3 /* Bits -> Bytes. */ | |
| 138 | DO_RET(lr) | |
| 139 | ||
| 140 | .Lmisaligned8: | |
| 141 | cfi_restore_state | |
| 142 | ldrd data1a, data1b, [src] | |
| 143 | and tmp2, tmp1, #3 | |
| 144 | rsb result, tmp1, #0 | |
| 145 | lsl tmp2, tmp2, #3 /* Bytes -> bits. */ | |
| 146 | tst tmp1, #4 | |
| 147 | pld [src, #64] | |
| 148 | S2HI tmp2, const_m1, tmp2 | |
| 21bfcecf RM |
149 | #ifdef NO_THUMB |
| 150 | mvn tmp1, tmp2 | |
| 151 | orr data1a, data1a, tmp1 | |
| 152 | itt ne | |
| 153 | orrne data1b, data1b, tmp1 | |
| 154 | #else | |
| 2601bc18 WN |
155 | orn data1a, data1a, tmp2 |
| 156 | itt ne | |
| 157 | ornne data1b, data1b, tmp2 | |
| 21bfcecf | 158 | #endif |
| 2601bc18 WN |
159 | movne data1a, const_m1 |
| 160 | mov const_0, #0 | |
| 161 | b .Lstart_realigned | |
| 162 | ||
| 163 | END(strlen) | |
| 164 | libc_hidden_builtin_def (strlen) |