memmove.S revision 1.2
1 /* $NetBSD: memmove.S,v 1.2 2008/03/06 21:17:17 phx Exp $ */ 2 3 /* stropt/memmove.S, pl_string_common, pl_linux 10/11/04 11:45:37 4 * ========================================================================== 5 * Optimized memmove implementation for IBM PowerPC 405/440. 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: Move memory area (handles overlapping regions) 41 * 42 * void *memmove(void * dest, const void * src, int n) 43 * 44 * Input: r3 - destination address 45 * r4 - source address 46 * r5 - byte count 47 * Output: r3 - destination address 48 * 49 * ========================================================================== 50 */ 51 52 #define _NOREGNAMES 53 #include <machine/asm.h> 54 55 .text 56 .align 4 57 #ifdef _BCOPY 58 /* bcopy = memcpy/memmove with arguments reversed. */ 59 /* LINTSTUB: Func: void bcopy(void *, void *, size_t) */ 60 ENTRY(bcopy) 61 mr %r6, %r3 /* swap src/dst */ 62 mr %r3, %r4 63 mr %r4, %r6 64 #else 65 /* LINTSTUB: Func: void *memmove(void *, const void *, size_t) */ 66 ENTRY(memmove) 67 #endif 68 69 mr %r8, %r3 /* Save dst (return value) */ 70 71 cmpw %r4, %r8 /* Branch to reverse if */ 72 blt reverse /* src < dest. Don't want to */ 73 /* overwrite end of src with */ 74 /* start of dest */ 75 76 addi %r4, %r4, -4 /* Back up src and dst pointers */ 77 addi %r8, %r8, -4 /* due to auto-update of 'load' */ 78 79 srwi. %r9,%r5,2 /* How many words in total cnt */ 80 beq- last1 /* Handle byte by byte if < 4 */ 81 /* bytes total */ 82 mtctr %r9 /* Count of words for loop */ 83 lwzu %r7, 4(%r4) /* Preload first word */ 84 85 b g1 86 87 g0: /* Main loop */ 88 89 lwzu %r7, 4(%r4) /* Load a new word */ 90 stwu %r6, 4(%r8) /* Store previous word */ 91 92 g1: 93 94 bdz- last /* Dec cnt, and branch if just */ 95 /* one word to store */ 96 lwzu %r6, 4(%r4) /* Load another word */ 97 stwu %r7, 4(%r8) /* Store previous word */ 98 bdnz+ g0 /* Dec cnt, and loop again if */ 99 /* more words */ 100 mr %r7, %r6 /* If word count -> 0, then... */ 101 102 last: 103 104 stwu %r7, 4(%r8) /* ... store last word */ 105 106 last1: /* Byte-by-byte copy */ 107 108 clrlwi. %r5,%r5,30 /* If count -> 0, then ... */ 109 beqlr /* we're done */ 110 111 mtctr %r5 /* else load count for loop */ 112 113 lbzu %r6, 4(%r4) /* 1st byte: update addr by 4 */ 114 stbu %r6, 4(%r8) /* since we pre-adjusted by 4 */ 115 bdzlr- /* in anticipation of main loop */ 116 117 last2: 118 119 lbzu %r6, 1(%r4) /* But handle the rest by */ 120 stbu %r6, 1(%r8) /* updating addr by 1 */ 121 bdnz+ last2 122 123 blr 124 125 /* We're here since src < dest. Don't want to overwrite end of */ 126 /* src with start of dest */ 127 128 reverse: 129 130 add %r4, %r4, %r5 /* Work from end to beginning */ 131 add %r8, %r8, %r5 /* so add count to string ptrs */ 132 srwi. %r9,%r5,2 /* Words in total count */ 133 beq- rlast1 /* Handle byte by byte if < 4 */ 134 /* bytes total */ 135 136 mtctr %r9 /* Count of words for loop */ 137 138 lwzu %r7, -4(%r4) /* Preload first word */ 139 b rg1 140 141 rg0: /* Main loop */ 142 143 lwzu %r7, -4(%r4) /* Load a new word */ 144 stwu %r6, -4(%r8) /* Store previous word */ 145 146 rg1: 147 148 bdz- rlast /* Dec cnt, and branch if just */ 149 /* one word to store */ 150 151 lwzu %r6, -4(%r4) /* Load another word */ 152 stwu %r7, -4(%r8) /* Store previous word */ 153 154 bdnz+ rg0 /* Dec cnt, and loop again if */ 155 /* more words */ 156 157 mr %r7, %r6 /* If word count -> 0, then... */ 158 159 rlast: 160 161 stwu %r7, -4(%r8) /* ... store last word */ 162 163 rlast1: /* Byte-by-byte copy */ 164 165 clrlwi. %r5,%r5,30 /* If count -> 0, then... */ 166 beqlr /* ... we're done */ 167 168 mtctr %r5 /* else load count for loop */ 169 170 rlast2: 171 172 lbzu %r6, -1(%r4) /* Handle the rest, byte by */ 173 stbu %r6, -1(%r8) /* byte */ 174 175 bdnz+ rlast2 /* Dec ctr, and branch if more */ 176 /* bytes left */ 177 blr 178 179
Indexes created Tue Oct 14 01:09:49 GMT 2025