1/* $NetBSD: memcpy.S,v 1.1 2008/02/21 17:35:47 garbled 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#ifdef _KERNEL 57#include <assym.h> 58#endif 59 60 .text 61 .align 4 62/* LINTSTUB: Func: void *memcpy(void *, const void *, size_t) */ 63ENTRY(memcpy) 64 /* 65 * Check count passed in R5. If zero, return; otherwise continue. 66 */ 67 cmpwi %r5,0 68 beqlr- 69 70 mr %r8, %r3 /* Copy dst (return value) */ 71 72 addi %r4, %r4, -4 /* Prepare for main loop's auto */ 73 addi %r8, %r8, -4 /* update */ 74 75 srwi. %r9,%r5,2 /* Word count -> r9 */ 76 beq- last1 /* Partial copy if <4 bytes */ 77 78 mtctr %r9 /* Word cnt in CTR for loop */ 79 lwzu %r7, 4(%r4) /* Preload for main loop */ 80 81 b g1 82 83g0: /* Main loop */ 84 85 lwzu %r7, 4(%r4) /* Load a new word */ 86 stwu %r6, 4(%r8) /* Store previous word */ 87 88g1: 89 90 bdz- last /* Dec ctr and exit loop if no */ 91 /* more words */ 92 lwzu %r6, 4(%r4) /* Load another word */ 93 stwu %r7, 4(%r8) /* Store previous word */ 94 bdnz+ g0 /* Dec ctr and continue loop if */ 95 /* more words */ 96 97 mr %r7, %r6 98 99last: 100 101 stwu %r7, 4(%r8) /* Store last word */ 102 103last1: /* Byte-by-byte copy */ 104 105 clrlwi. %r5,%r5,30 106 beqlr 107 108 mtctr %r5 109 110 lbzu %r6, 4(%r4) /* 1st byte: update by word */ 111 stbu %r6, 4(%r8) 112 bdzlr- 113 114last2: 115 116 lbzu %r6, 1(%r4) /* Handle the rest */ 117 stbu %r6, 1(%r8) 118 bdnz+ last2 119 120 blr 121 122