1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <private/bionic_asm.h> 30 31 /* 32 * Optimized memset() for ARM. 33 * 34 * memset() returns its first argument. 35 */ 36 37 .syntax unified 38 39 ENTRY(__memset_chk) 40 cmp r2, r3 41 bls memset 42 43 bl __memset_chk_fail 44 END(__memset_chk) 45 46 ENTRY(memset) 47 /* compute the offset to align the destination 48 * offset = (4-(src&3))&3 = -src & 3 49 */ 50 .save {r0, r4-r7, lr} 51 stmfd sp!, {r0, r4-r7, lr} 52 rsb r3, r0, #0 53 ands r3, r3, #3 54 cmp r3, r2 55 movhi r3, r2 56 57 /* splat r1 */ 58 mov r1, r1, lsl #24 59 orr r1, r1, r1, lsr #8 60 orr r1, r1, r1, lsr #16 61 62 movs r12, r3, lsl #31 63 strbcs r1, [r0], #1 /* can't use strh (alignment unknown) */ 64 strbcs r1, [r0], #1 65 strbmi r1, [r0], #1 66 subs r2, r2, r3 67 popls {r0, r4-r7, pc} /* return */ 68 69 /* align the destination to a cache-line */ 70 mov r12, r1 71 mov lr, r1 72 mov r4, r1 73 mov r5, r1 74 mov r6, r1 75 mov r7, r1 76 77 rsb r3, r0, #0 78 ands r3, r3, #0x1C 79 beq 3f 80 cmp r3, r2 81 andhi r3, r2, #0x1C 82 sub r2, r2, r3 83 84 /* conditionally writes 0 to 7 words (length in r3) */ 85 movs r3, r3, lsl #28 86 stmcs r0!, {r1, lr} 87 stmcs r0!, {r1, lr} 88 stmmi r0!, {r1, lr} 89 movs r3, r3, lsl #2 90 strcs r1, [r0], #4 91 92 3: 93 subs r2, r2, #32 94 mov r3, r1 95 bmi 2f 96 1: subs r2, r2, #32 97 stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr} 98 bhs 1b 99 2: add r2, r2, #32 100 101 /* conditionally stores 0 to 31 bytes */ 102 movs r2, r2, lsl #28 103 stmcs r0!, {r1,r3,r12,lr} 104 stmmi r0!, {r1, lr} 105 movs r2, r2, lsl #2 106 strcs r1, [r0], #4 107 strhmi r1, [r0], #2 108 movs r2, r2, lsl #2 109 strbcs r1, [r0] 110 ldmfd sp!, {r0, r4-r7, pc} 111 END(memset) 112
