1/* $NetBSD: memcpy.S,v 1.1 2014/08/10 05:47:35 matt Exp $ */ 2 3/*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <machine/asm.h> 33 34RCSID("$NetBSD: memcpy.S,v 1.1 2014/08/10 05:47:35 matt Exp $") 35 36/* LINTSTUB: void *memcpy(void * restrict, const void * restrict, size_t); */ 37 38ENTRY(memcpy) 39 mov x10, x0 40 mov x11, x1 41 cbz x2, .Lmemcpy_ret 42 43 cmp x2, #7 44 b.ls .Lmemcpy_last_dword 45 46 ands x3, x10, #7 47 b.eq .Lmemcpy_dword_aligned 48 49/* 50 * The dst address doesn't have dword alignment. The src address may or may 51 * not have the same alignment. Make dst dword aligned. Hope src will be 52 * dword aligned but if it isn't, take advantage of unaligned access. 53 */ 54 add x2, x2, x3 /* add unalignment to length */ 55 sub x2, x2, #8 /* now subtract a dword */ 56 57 tbz x10, #0, .Lmemcpy_hword_aligned 58 ldrb w4, [x11], #1 59 strb w4, [x10], #1 60.Lmemcpy_hword_aligned: 61 tbz x10, #1, .Lmemcpy_word_aligned 62 ldrh w4, [x11], #2 63 strh w4, [x10], #2 64.Lmemcpy_word_aligned: 65 tbz x10, #2, .Lmemcpy_dword_aligned 66 ldr w4, [x11], #4 67 str w4, [x10], #4 68.Lmemcpy_dword_aligned: 69 /* 70 * destination is now dword aligned. 71 */ 72 subs x2, x2, #32 73 b.mi .Lmemcpy_last_oword 74 75.Lmemcpy_oword_loop: 76 ldp x4, x5, [x11], #16 77 ldp x6, x7, [x11], #16 78 stp x4, x5, [x10], #16 79 stp x6, x7, [x10], #16 80 cbz x2, .Lmemcpy_ret 81 subs x2, x2, #32 82 b.pl .Lmemcpy_oword_loop 83 84.Lmemcpy_last_oword: 85 /* 86 * We have 31 bytes or less to copy. First see if we can write a qword 87 */ 88 tbz x2, #4, .Lmemcpy_last_qword 89 ldp x4, x5, [x11], #16 /* read word */ 90 stp x4, x5, [x10], #16 /* write word */ 91 92.Lmemcpy_last_qword: 93 /* 94 * We have 15 bytes or less to copy. First see if we can write a dword 95 */ 96 tbz x2, #3, .Lmemcpy_last_dword 97 ldr x4, [x11], #8 /* read word */ 98 str x4, [x10], #8 /* write word */ 99 100.Lmemcpy_last_dword: 101 /* 102 * We have 7 bytes or less to copy. First see if we can write a word 103 */ 104 tbz x2, #2, .Lmemcpy_last_word 105 ldr w4, [x11], #4 /* read word */ 106 str w4, [x10], #4 /* write word */ 107 108.Lmemcpy_last_word: 109 /* 110 * We have 3 bytes or less to copy. First see if we can write a hword 111 */ 112 tbz x2, #1, .Lmemcpy_last_hword 113 ldrh w4, [x11], #2 114 strh w4, [x10], #2 115 116.Lmemcpy_last_hword: 117 /* 118 * We have 1 or none bytes to copy. 119 */ 120 tbz x2, #0, .Lmemcpy_ret 121 ldrb w4, [x11] 122 strb w4, [x10] 123 124.Lmemcpy_ret: 125 ret 126END(memcpy) 127