1/* $NetBSD: memcpy.S,v 1.2 2008/03/06 21:17:17 phx Exp $ */ 2 3/* stropt/memcpy_440.S, pl_string_common, pl_linux 10/11/04 11:45:36 4 * ========================================================================== 5 * Optimized memcpy implementation for IBM PowerPC 440. 6 * 7 * Copyright (c) 2003, IBM Corporation 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or 11 * without modification, are permitted provided that the following 12 * conditions are met: 13 * 14 * * Redistributions of source code must retain the above 15 * copyright notice, this list of conditions and the following 16 * disclaimer. 17 * * Redistributions in binary form must reproduce the above 18 * copyright notice, this list of conditions and the following 19 * disclaimer in the documentation and/or other materials 20 * provided with the distribution. 21 * * Neither the name of IBM nor the names of its contributors 22 * may be used to endorse or promote products derived from this 23 * software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 26 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 27 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 28 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 29 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 31 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 34 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 36 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * ========================================================================== 39 * 40 * Function: Copy n bytes of the source to the destination. Behavior is 41 * undefined for objects that overlap. 42 * 43 * 44 * void *memcpy(void * dest, const void * src, int n) 45 * 46 * Input: r3 - destination address 47 * r4 - source address 48 * r5 - byte count 49 * Output: r3 - destination address 50 * 51 * ========================================================================== 52 */ 53 54#define _NOREGNAMES 55#include <machine/asm.h> 56 57 .text 58 .align 4 59/* LINTSTUB: Func: void *memcpy(void *, const void *, size_t) */ 60ENTRY(memcpy) 61 /* 62 * Check count passed in R5. If zero, return; otherwise continue. 63 */ 64 cmpwi %r5,0 65 beqlr- 66 67 mr %r8, %r3 /* Copy dst (return value) */ 68 69 addi %r4, %r4, -4 /* Prepare for main loop's auto */ 70 addi %r8, %r8, -4 /* update */ 71 72 srwi. %r9,%r5,2 /* Word count -> r9 */ 73 beq- last1 /* Partial copy if <4 bytes */ 74 75 mtctr %r9 /* Word cnt in CTR for loop */ 76 lwzu %r7, 4(%r4) /* Preload for main loop */ 77 78 b g1 79 80g0: /* Main loop */ 81 82 lwzu %r7, 4(%r4) /* Load a new word */ 83 stwu %r6, 4(%r8) /* Store previous word */ 84 85g1: 86 87 bdz- last /* Dec ctr and exit loop if no */ 88 /* more words */ 89 lwzu %r6, 4(%r4) /* Load another word */ 90 stwu %r7, 4(%r8) /* Store previous word */ 91 bdnz+ g0 /* Dec ctr and continue loop if */ 92 /* more words */ 93 94 mr %r7, %r6 95 96last: 97 98 stwu %r7, 4(%r8) /* Store last word */ 99 100last1: /* Byte-by-byte copy */ 101 102 clrlwi. %r5,%r5,30 103 beqlr 104 105 mtctr %r5 106 107 lbzu %r6, 4(%r4) /* 1st byte: update by word */ 108 stbu %r6, 4(%r8) 109 bdzlr- 110 111last2: 112 113 lbzu %r6, 1(%r4) /* Handle the rest */ 114 stbu %r6, 1(%r8) 115 bdnz+ last2 116 117 blr 118 119