| 1 | /* |
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| 2 | * Copyright (c) 2014 ARM Ltd |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * 1. Redistributions of source code must retain the above copyright |
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| 9 | * notice, this list of conditions and the following disclaimer. |
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| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 11 | * notice, this list of conditions and the following disclaimer in the |
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| 12 | * documentation and/or other materials provided with the distribution. |
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| 13 | * 3. The name of the company may not be used to endorse or promote |
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| 14 | * products derived from this software without specific prior written |
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| 15 | * permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED |
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| 18 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
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| 19 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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| 21 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
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| 22 | * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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| 23 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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| 24 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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| 25 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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| 26 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |
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| 29 | /* Implementation of strcmp for ARMv6m. This version is only used in |
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| 30 | ARMv6-M when we want an efficient implementation. Otherwize if the |
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| 31 | code size is preferred, strcmp-armv4t.S will be used. */ |
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| 32 | |
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| 33 | .thumb_func |
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| 34 | .syntax unified |
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| 35 | .arch armv6-m |
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| 36 | |
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| 37 | .macro DoSub n, label |
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| 38 | subs r0, r0, r1 |
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| 39 | #ifdef __ARM_BIG_ENDIAN |
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| 40 | lsrs r1, r4, \n |
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| 41 | #else |
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| 42 | lsls r1, r4, \n |
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| 43 | #endif |
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| 44 | orrs r1, r0 |
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| 45 | bne \label |
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| 46 | .endm |
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| 47 | |
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| 48 | .macro Byte_Test n, label |
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| 49 | lsrs r0, r2, \n |
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| 50 | lsrs r1, r3, \n |
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| 51 | DoSub \n, \label |
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| 52 | .endm |
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| 53 | |
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| 54 | .text |
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| 55 | def_fn strcmp |
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| 56 | .cfi_sections .debug_frame |
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| 57 | .cfi_startproc |
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| 58 | mov r2, r0 |
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| 59 | push {r4, r5, r6, lr} |
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| 60 | orrs r2, r1 |
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| 61 | lsls r2, r2, #30 |
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| 62 | bne 6f |
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| 63 | ldr r5, =0x01010101 |
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| 64 | lsls r6, r5, #7 |
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| 65 | 1: |
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| 66 | ldmia r0!, {r2} |
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| 67 | ldmia r1!, {r3} |
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| 68 | subs r4, r2, r5 |
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| 69 | bics r4, r2 |
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| 70 | ands r4, r6 |
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| 71 | beq 3f |
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| 72 | |
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| 73 | #ifdef __ARM_BIG_ENDIAN |
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| 74 | Byte_Test #24, 4f |
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| 75 | Byte_Test #16, 4f |
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| 76 | Byte_Test #8, 4f |
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| 77 | |
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| 78 | b 7f |
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| 79 | 3: |
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| 80 | cmp r2, r3 |
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| 81 | beq 1b |
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| 82 | cmp r2, r3 |
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| 83 | #else |
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| 84 | uxtb r0, r2 |
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| 85 | uxtb r1, r3 |
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| 86 | DoSub #24, 2f |
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| 87 | |
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| 88 | uxth r0, r2 |
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| 89 | uxth r1, r3 |
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| 90 | DoSub #16, 2f |
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| 91 | |
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| 92 | lsls r0, r2, #8 |
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| 93 | lsls r1, r3, #8 |
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| 94 | lsrs r0, r0, #8 |
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| 95 | lsrs r1, r1, #8 |
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| 96 | DoSub #8, 2f |
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| 97 | |
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| 98 | lsrs r0, r2, #24 |
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| 99 | lsrs r1, r3, #24 |
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| 100 | subs r0, r0, r1 |
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| 101 | 2: |
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| 102 | pop {r4, r5, r6, pc} |
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| 103 | |
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| 104 | 3: |
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| 105 | cmp r2, r3 |
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| 106 | beq 1b |
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| 107 | rev r0, r2 |
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| 108 | rev r1, r3 |
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| 109 | cmp r0, r1 |
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| 110 | #endif |
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| 111 | |
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| 112 | bls 5f |
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| 113 | movs r0, #1 |
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| 114 | 4: |
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| 115 | pop {r4, r5, r6, pc} |
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| 116 | 5: |
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| 117 | movs r0, #0 |
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| 118 | mvns r0, r0 |
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| 119 | pop {r4, r5, r6, pc} |
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| 120 | 6: |
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| 121 | ldrb r2, [r0, #0] |
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| 122 | ldrb r3, [r1, #0] |
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| 123 | adds r0, #1 |
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| 124 | adds r1, #1 |
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| 125 | cmp r2, #0 |
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| 126 | beq 7f |
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| 127 | cmp r2, r3 |
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| 128 | bne 7f |
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| 129 | ldrb r2, [r0, #0] |
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| 130 | ldrb r3, [r1, #0] |
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| 131 | adds r0, #1 |
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| 132 | adds r1, #1 |
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| 133 | cmp r2, #0 |
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| 134 | beq 7f |
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| 135 | cmp r2, r3 |
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| 136 | beq 6b |
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| 137 | 7: |
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| 138 | subs r0, r2, r3 |
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| 139 | pop {r4, r5, r6, pc} |
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| 140 | .cfi_endproc |
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| 141 | .size strcmp, . - strcmp |
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