bcopy.S revision 1.1
1 /* $NetBSD: bcopy.S,v 1.1 2005/12/20 19:28:49 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Carnegie-Mellon University. 5 * All rights reserved. 6 * 7 * Author: Trevor Blackwell. Support for use as memcpy() and memmove() 8 * added by Chris Demetriou. 9 * 10 * Permission to use, copy, modify and distribute this software and 11 * its documentation is hereby granted, provided that both the copyright 12 * notice and this permission notice appear in all copies of the 13 * software, derivative works or modified versions, and any portions 14 * thereof, and that both notices appear in supporting documentation. 15 * 16 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 17 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 18 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 19 * 20 * Carnegie Mellon requests users of this software to return to 21 * 22 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU 23 * School of Computer Science 24 * Carnegie Mellon University 25 * Pittsburgh PA 15213-3890 26 * 27 * any improvements or extensions that they make and grant Carnegie the 28 * rights to redistribute these changes. 29 */ 30 31 #include <machine/asm.h> 32 33 #if defined(MEMCOPY) || defined(MEMMOVE) 34 #ifdef MEMCOPY 35 #define FUNCTION memcpy 36 #else 37 #define FUNCTION memmove 38 #endif 39 #define SRCREG a1 40 #define DSTREG a0 41 #else /* !(defined(MEMCOPY) || defined(MEMMOVE)) */ 42 #define FUNCTION bcopy 43 #define SRCREG a0 44 #define DSTREG a1 45 #endif /* !(defined(MEMCOPY) || defined(MEMMOVE)) */ 46 47 #define SIZEREG a2 48 49 /* 50 * Copy bytes. 51 * 52 * void bcopy(char *from, char *to, size_t len); 53 * char *memcpy(void *to, const void *from, size_t len); 54 * char *memmove(void *to, const void *from, size_t len); 55 * 56 * No matter how invoked, the source and destination registers 57 * for calculation. There's no point in copying them to "working" 58 * registers, since the code uses their values "in place," and 59 * copying them would be slower. 60 */ 61 62 LEAF(FUNCTION,3) 63 64 #if defined(MEMCOPY) || defined(MEMMOVE) 65 /* set up return value, while we still can */ 66 mov DSTREG,v0 67 #endif 68 69 /* Check for negative length */ 70 ble SIZEREG,bcopy_done 71 72 /* Check for overlap */ 73 subq DSTREG,SRCREG,t5 74 cmpult t5,SIZEREG,t5 75 bne t5,bcopy_overlap 76 77 /* a3 = end address */ 78 addq SRCREG,SIZEREG,a3 79 80 /* Get the first word */ 81 ldq_u t2,0(SRCREG) 82 83 /* Do they have the same alignment? */ 84 xor SRCREG,DSTREG,t0 85 and t0,7,t0 86 and DSTREG,7,t1 87 bne t0,bcopy_different_alignment 88 89 /* src & dst have same alignment */ 90 beq t1,bcopy_all_aligned 91 92 ldq_u t3,0(DSTREG) 93 addq SIZEREG,t1,SIZEREG 94 mskqh t2,SRCREG,t2 95 mskql t3,SRCREG,t3 96 or t2,t3,t2 97 98 /* Dst is 8-byte aligned */ 99 100 bcopy_all_aligned: 101 /* If less than 8 bytes,skip loop */ 102 subq SIZEREG,1,t0 103 and SIZEREG,7,SIZEREG 104 bic t0,7,t0 105 beq t0,bcopy_samealign_lp_end 106 107 bcopy_samealign_lp: 108 stq_u t2,0(DSTREG) 109 addq DSTREG,8,DSTREG 110 ldq_u t2,8(SRCREG) 111 subq t0,8,t0 112 addq SRCREG,8,SRCREG 113 bne t0,bcopy_samealign_lp 114 115 bcopy_samealign_lp_end: 116 /* If we're done, exit */ 117 bne SIZEREG,bcopy_small_left 118 stq_u t2,0(DSTREG) 119 RET 120 121 bcopy_small_left: 122 mskql t2,SIZEREG,t4 123 ldq_u t3,0(DSTREG) 124 mskqh t3,SIZEREG,t3 125 or t4,t3,t4 126 stq_u t4,0(DSTREG) 127 RET 128 129 bcopy_different_alignment: 130 /* 131 * this is the fun part 132 */ 133 addq SRCREG,SIZEREG,a3 134 cmpule SIZEREG,8,t0 135 bne t0,bcopy_da_finish 136 137 beq t1,bcopy_da_noentry 138 139 /* Do the initial partial word */ 140 subq zero,DSTREG,t0 141 and t0,7,t0 142 ldq_u t3,7(SRCREG) 143 extql t2,SRCREG,t2 144 extqh t3,SRCREG,t3 145 or t2,t3,t5 146 insql t5,DSTREG,t5 147 ldq_u t6,0(DSTREG) 148 mskql t6,DSTREG,t6 149 or t5,t6,t5 150 stq_u t5,0(DSTREG) 151 addq SRCREG,t0,SRCREG 152 addq DSTREG,t0,DSTREG 153 subq SIZEREG,t0,SIZEREG 154 ldq_u t2,0(SRCREG) 155 156 bcopy_da_noentry: 157 subq SIZEREG,1,t0 158 bic t0,7,t0 159 and SIZEREG,7,SIZEREG 160 beq t0,bcopy_da_finish2 161 162 bcopy_da_lp: 163 ldq_u t3,7(SRCREG) 164 addq SRCREG,8,SRCREG 165 extql t2,SRCREG,t4 166 extqh t3,SRCREG,t5 167 subq t0,8,t0 168 or t4,t5,t5 169 stq t5,0(DSTREG) 170 addq DSTREG,8,DSTREG 171 beq t0,bcopy_da_finish1 172 ldq_u t2,7(SRCREG) 173 addq SRCREG,8,SRCREG 174 extql t3,SRCREG,t4 175 extqh t2,SRCREG,t5 176 subq t0,8,t0 177 or t4,t5,t5 178 stq t5,0(DSTREG) 179 addq DSTREG,8,DSTREG 180 bne t0,bcopy_da_lp 181 182 bcopy_da_finish2: 183 /* Do the last new word */ 184 mov t2,t3 185 186 bcopy_da_finish1: 187 /* Do the last partial word */ 188 ldq_u t2,-1(a3) 189 extql t3,SRCREG,t3 190 extqh t2,SRCREG,t2 191 or t2,t3,t2 192 br zero,bcopy_samealign_lp_end 193 194 bcopy_da_finish: 195 /* Do the last word in the next source word */ 196 ldq_u t3,-1(a3) 197 extql t2,SRCREG,t2 198 extqh t3,SRCREG,t3 199 or t2,t3,t2 200 insqh t2,DSTREG,t3 201 insql t2,DSTREG,t2 202 lda t4,-1(zero) 203 mskql t4,SIZEREG,t5 204 cmovne t5,t5,t4 205 insqh t4,DSTREG,t5 206 insql t4,DSTREG,t4 207 addq DSTREG,SIZEREG,a4 208 ldq_u t6,0(DSTREG) 209 ldq_u t7,-1(a4) 210 bic t6,t4,t6 211 bic t7,t5,t7 212 and t2,t4,t2 213 and t3,t5,t3 214 or t2,t6,t2 215 or t3,t7,t3 216 stq_u t3,-1(a4) 217 stq_u t2,0(DSTREG) 218 RET 219 220 bcopy_overlap: 221 /* 222 * Basically equivalent to previous case, only backwards. 223 * Not quite as highly optimized 224 */ 225 addq SRCREG,SIZEREG,a3 226 addq DSTREG,SIZEREG,a4 227 228 /* less than 8 bytes - don't worry about overlap */ 229 cmpule SIZEREG,8,t0 230 bne t0,bcopy_ov_short 231 232 /* Possibly do a partial first word */ 233 and a4,7,t4 234 beq t4,bcopy_ov_nostart2 235 subq a3,t4,a3 236 subq a4,t4,a4 237 ldq_u t1,0(a3) 238 subq SIZEREG,t4,SIZEREG 239 ldq_u t2,7(a3) 240 ldq t3,0(a4) 241 extql t1,a3,t1 242 extqh t2,a3,t2 243 or t1,t2,t1 244 mskqh t3,t4,t3 245 mskql t1,t4,t1 246 or t1,t3,t1 247 stq t1,0(a4) 248 249 bcopy_ov_nostart2: 250 bic SIZEREG,7,t4 251 and SIZEREG,7,SIZEREG 252 beq t4,bcopy_ov_lp_end 253 254 bcopy_ov_lp: 255 /* This could be more pipelined, but it doesn't seem worth it */ 256 ldq_u t0,-8(a3) 257 subq a4,8,a4 258 ldq_u t1,-1(a3) 259 subq a3,8,a3 260 extql t0,a3,t0 261 extqh t1,a3,t1 262 subq t4,8,t4 263 or t0,t1,t0 264 stq t0,0(a4) 265 bne t4,bcopy_ov_lp 266 267 bcopy_ov_lp_end: 268 beq SIZEREG,bcopy_done 269 270 ldq_u t0,0(SRCREG) 271 ldq_u t1,7(SRCREG) 272 ldq_u t2,0(DSTREG) 273 extql t0,SRCREG,t0 274 extqh t1,SRCREG,t1 275 or t0,t1,t0 276 insql t0,DSTREG,t0 277 mskql t2,DSTREG,t2 278 or t2,t0,t2 279 stq_u t2,0(DSTREG) 280 281 bcopy_done: 282 RET 283 284 bcopy_ov_short: 285 ldq_u t2,0(SRCREG) 286 br zero,bcopy_da_finish 287 288 END(FUNCTION) 289
Indexes created Wed Sep 24 15:09:51 GMT 2025