memmove.S revision 1.3
1 /* $NetBSD: memmove.S,v 1.3 2011/01/15 07:31:12 matt 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 #include <machine/asm.h> 53 54 .text 55 .align 4 56 #ifdef _BCOPY 57 /* bcopy = memcpy/memmove with arguments reversed. */ 58 /* LINTSTUB: Func: void bcopy(void *, void *, size_t) */ 59 ENTRY(bcopy) 60 mr %r6, %r3 /* swap src/dst */ 61 mr %r3, %r4 62 mr %r4, %r6 63 #else 64 /* LINTSTUB: Func: void *memmove(void *, const void *, size_t) */ 65 ENTRY(memmove) 66 #endif 67 68 mr %r8, %r3 /* Save dst (return value) */ 69 70 cmpw %r4, %r8 /* Branch to reverse if */ 71 blt reverse /* src < dest. Don't want to */ 72 /* overwrite end of src with */ 73 /* start of dest */ 74 75 addi %r4, %r4, -4 /* Back up src and dst pointers */ 76 addi %r8, %r8, -4 /* due to auto-update of 'load' */ 77 78 srwi. %r9,%r5,2 /* How many words in total cnt */ 79 beq- last1 /* Handle byte by byte if < 4 */ 80 /* bytes total */ 81 mtctr %r9 /* Count of words for loop */ 82 lwzu %r7, 4(%r4) /* Preload first word */ 83 84 b g1 85 86 g0: /* Main loop */ 87 88 lwzu %r7, 4(%r4) /* Load a new word */ 89 stwu %r6, 4(%r8) /* Store previous word */ 90 91 g1: 92 93 bdz- last /* Dec cnt, and branch if just */ 94 /* one word to store */ 95 lwzu %r6, 4(%r4) /* Load another word */ 96 stwu %r7, 4(%r8) /* Store previous word */ 97 bdnz+ g0 /* Dec cnt, and loop again if */ 98 /* more words */ 99 mr %r7, %r6 /* If word count -> 0, then... */ 100 101 last: 102 103 stwu %r7, 4(%r8) /* ... store last word */ 104 105 last1: /* Byte-by-byte copy */ 106 107 clrlwi. %r5,%r5,30 /* If count -> 0, then ... */ 108 beqlr /* we're done */ 109 110 mtctr %r5 /* else load count for loop */ 111 112 lbzu %r6, 4(%r4) /* 1st byte: update addr by 4 */ 113 stbu %r6, 4(%r8) /* since we pre-adjusted by 4 */ 114 bdzlr- /* in anticipation of main loop */ 115 116 last2: 117 118 lbzu %r6, 1(%r4) /* But handle the rest by */ 119 stbu %r6, 1(%r8) /* updating addr by 1 */ 120 bdnz+ last2 121 122 blr 123 124 /* We're here since src < dest. Don't want to overwrite end of */ 125 /* src with start of dest */ 126 127 reverse: 128 129 add %r4, %r4, %r5 /* Work from end to beginning */ 130 add %r8, %r8, %r5 /* so add count to string ptrs */ 131 srwi. %r9,%r5,2 /* Words in total count */ 132 beq- rlast1 /* Handle byte by byte if < 4 */ 133 /* bytes total */ 134 135 mtctr %r9 /* Count of words for loop */ 136 137 lwzu %r7, -4(%r4) /* Preload first word */ 138 b rg1 139 140 rg0: /* Main loop */ 141 142 lwzu %r7, -4(%r4) /* Load a new word */ 143 stwu %r6, -4(%r8) /* Store previous word */ 144 145 rg1: 146 147 bdz- rlast /* Dec cnt, and branch if just */ 148 /* one word to store */ 149 150 lwzu %r6, -4(%r4) /* Load another word */ 151 stwu %r7, -4(%r8) /* Store previous word */ 152 153 bdnz+ rg0 /* Dec cnt, and loop again if */ 154 /* more words */ 155 156 mr %r7, %r6 /* If word count -> 0, then... */ 157 158 rlast: 159 160 stwu %r7, -4(%r8) /* ... store last word */ 161 162 rlast1: /* Byte-by-byte copy */ 163 164 clrlwi. %r5,%r5,30 /* If count -> 0, then... */ 165 beqlr /* ... we're done */ 166 167 mtctr %r5 /* else load count for loop */ 168 169 rlast2: 170 171 lbzu %r6, -1(%r4) /* Handle the rest, byte by */ 172 stbu %r6, -1(%r8) /* byte */ 173 174 bdnz+ rlast2 /* Dec ctr, and branch if more */ 175 /* bytes left */ 176 blr 177 178 #ifdef _BCOPY 179 END(bcopy) 180 #else 181 END(memmove) 182 #endif 183
Indexes created Tue Oct 14 01:09:49 GMT 2025