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 .text 29 30 .global memset 31 .type memset, %function 32 33 .global bzero 34 .type bzero, %function 35 36 .align 37 38 /* 39 * Optimized memset() for ARM. 40 * 41 * memset() returns its first argument. 42 */ 43 44bzero: 45 mov r2, r1 46 mov r1, #0 47 48memset: 49 /* compute the offset to align the destination 50 * offset = (4-(src&3))&3 = -src & 3 51 */ 52 .fnstart 53 .save {r0, r4-r7, lr} 54 stmfd sp!, {r0, r4-r7, lr} 55 rsb r3, r0, #0 56 ands r3, r3, #3 57 cmp r3, r2 58 movhi r3, r2 59 60 /* splat r1 */ 61 mov r1, r1, lsl #24 62 orr r1, r1, r1, lsr #8 63 orr r1, r1, r1, lsr #16 64 65 movs r12, r3, lsl #31 66 strcsb r1, [r0], #1 /* can't use strh (alignment unknown) */ 67 strcsb r1, [r0], #1 68 strmib r1, [r0], #1 69 subs r2, r2, r3 70 ldmlsfd sp!, {r0, r4-r7, lr} /* return */ 71 bxls lr 72 73 /* align the destination to a cache-line */ 74 mov r12, r1 75 mov lr, r1 76 mov r4, r1 77 mov r5, r1 78 mov r6, r1 79 mov r7, r1 80 81 rsb r3, r0, #0 82 ands r3, r3, #0x1C 83 beq aligned32 84 cmp r3, r2 85 andhi r3, r2, #0x1C 86 sub r2, r2, r3 87 88 /* conditionnaly writes 0 to 7 words (length in r3) */ 89 movs r3, r3, lsl #28 90 stmcsia r0!, {r1, lr} 91 stmcsia r0!, {r1, lr} 92 stmmiia r0!, {r1, lr} 93 movs r3, r3, lsl #2 94 strcs r1, [r0], #4 95 96aligned32: 97 subs r2, r2, #32 98 mov r3, r1 99 bmi 2f 1001: subs r2, r2, #32 101 stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr} 102 bhs 1b 1032: add r2, r2, #32 104 105 /* conditionnaly stores 0 to 31 bytes */ 106 movs r2, r2, lsl #28 107 stmcsia r0!, {r1,r3,r12,lr} 108 stmmiia r0!, {r1, lr} 109 movs r2, r2, lsl #2 110 strcs r1, [r0], #4 111 strmih r1, [r0], #2 112 movs r2, r2, lsl #2 113 strcsb r1, [r0] 114 ldmfd sp!, {r0, r4-r7, lr} 115 bx lr 116 .fnend 117 118