lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* A memcpy for CRIS. |
| 2 | Copyright (C) 1994-2008 Axis Communications. |
| 3 | All rights reserved. |
| 4 | |
| 5 | Redistribution and use in source and binary forms, with or without |
| 6 | modification, are permitted provided that the following conditions |
| 7 | are met: |
| 8 | |
| 9 | 1. Redistributions of source code must retain the above copyright |
| 10 | notice, this list of conditions and the following disclaimer. |
| 11 | |
| 12 | 2. Neither the name of Axis Communications nor the names of its |
| 13 | contributors may be used to endorse or promote products derived |
| 14 | from this software without specific prior written permission. |
| 15 | |
| 16 | THIS SOFTWARE IS PROVIDED BY AXIS COMMUNICATIONS AND ITS CONTRIBUTORS |
| 17 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL AXIS |
| 20 | COMMUNICATIONS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| 21 | INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 22 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 23 | SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 24 | HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 25 | STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| 26 | IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 27 | POSSIBILITY OF SUCH DAMAGE. */ |
| 28 | |
| 29 | /* FIXME: This file should really only be used for reference, as the |
| 30 | result is somewhat depending on gcc generating what we expect rather |
| 31 | than what we describe. An assembly file should be used instead. */ |
| 32 | |
| 33 | #include <string.h> |
| 34 | |
| 35 | #ifdef __arch_v32 |
| 36 | /* For CRISv32, movem is very cheap. */ |
| 37 | #define MEMCPY_BY_BLOCK_THRESHOLD (44) |
| 38 | #else |
| 39 | /* Break even between movem and move16 is really at 38.7 * 2, but |
| 40 | modulo 44, so up to the next multiple of 44, we use ordinary code. */ |
| 41 | #define MEMCPY_BY_BLOCK_THRESHOLD (44 * 2) |
| 42 | #endif |
| 43 | |
| 44 | /* No name ambiguities in this file. */ |
| 45 | __asm__ (".syntax no_register_prefix"); |
| 46 | |
| 47 | void * |
| 48 | memcpy(void *pdst, const void *psrc, size_t pn) |
| 49 | { |
| 50 | /* Now we want the parameters put in special registers. |
| 51 | Make sure the compiler is able to make something useful of this. |
| 52 | As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). |
| 53 | |
| 54 | If gcc was allright, it really would need no temporaries, and no |
| 55 | stack space to save stuff on. */ |
| 56 | |
| 57 | register void *return_dst __asm__ ("r10") = pdst; |
| 58 | register unsigned char *dst __asm__ ("r13") = pdst; |
| 59 | register unsigned const char *src __asm__ ("r11") = psrc; |
| 60 | register int n __asm__ ("r12") = pn; |
| 61 | |
| 62 | /* When src is aligned but not dst, this makes a few extra needless |
| 63 | cycles. I believe it would take as many to check that the |
| 64 | re-alignment was unnecessary. */ |
| 65 | if (((unsigned long) dst & 3) != 0 |
| 66 | /* Don't align if we wouldn't copy more than a few bytes; so we |
| 67 | don't have to check further for overflows. */ |
| 68 | && n >= 3) |
| 69 | { |
| 70 | if ((unsigned long) dst & 1) |
| 71 | { |
| 72 | n--; |
| 73 | *dst = *src; |
| 74 | src++; |
| 75 | dst++; |
| 76 | } |
| 77 | |
| 78 | if ((unsigned long) dst & 2) |
| 79 | { |
| 80 | n -= 2; |
| 81 | *(short *) dst = *(short *) src; |
| 82 | src += 2; |
| 83 | dst += 2; |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | /* Decide which copying method to use. */ |
| 88 | if (n >= MEMCPY_BY_BLOCK_THRESHOLD) |
| 89 | { |
| 90 | /* It is not optimal to tell the compiler about clobbering any |
| 91 | registers; that will move the saving/restoring of those registers |
| 92 | to the function prologue/epilogue, and make non-movem sizes |
| 93 | suboptimal. */ |
| 94 | __asm__ __volatile__ |
| 95 | ("\ |
| 96 | ;; GCC does promise correct register allocations, but let's \n\ |
| 97 | ;; make sure it keeps its promises. \n\ |
| 98 | .ifnc %0-%1-%2,$r13-$r11-$r12 \n\ |
| 99 | .error \"GCC reg alloc bug: %0-%1-%4 != $r13-$r12-$r11\" \n\ |
| 100 | .endif \n\ |
| 101 | \n\ |
| 102 | ;; Save the registers we'll use in the movem process \n\ |
| 103 | ;; on the stack. \n\ |
| 104 | subq 11*4,sp \n\ |
| 105 | movem r10,[sp] \n\ |
| 106 | \n\ |
| 107 | ;; Now we've got this: \n\ |
| 108 | ;; r11 - src \n\ |
| 109 | ;; r13 - dst \n\ |
| 110 | ;; r12 - n \n\ |
| 111 | \n\ |
| 112 | ;; Update n for the first loop. \n\ |
| 113 | subq 44,r12 \n\ |
| 114 | 0: \n\ |
| 115 | " |
| 116 | #ifdef __arch_common_v10_v32 |
| 117 | /* Cater to branch offset difference between v32 and v10. We |
| 118 | assume the branch below has an 8-bit offset. */ |
| 119 | " setf\n" |
| 120 | #endif |
| 121 | " movem [r11+],r10 \n\ |
| 122 | subq 44,r12 \n\ |
| 123 | bge 0b \n\ |
| 124 | movem r10,[r13+] \n\ |
| 125 | \n\ |
| 126 | ;; Compensate for last loop underflowing n. \n\ |
| 127 | addq 44,r12 \n\ |
| 128 | \n\ |
| 129 | ;; Restore registers from stack. \n\ |
| 130 | movem [sp+],r10" |
| 131 | |
| 132 | /* Outputs. */ |
| 133 | : "=r" (dst), "=r" (src), "=r" (n) |
| 134 | |
| 135 | /* Inputs. */ |
| 136 | : "0" (dst), "1" (src), "2" (n)); |
| 137 | } |
| 138 | |
| 139 | while (n >= 16) |
| 140 | { |
| 141 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 142 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 143 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 144 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 145 | |
| 146 | n -= 16; |
| 147 | } |
| 148 | |
| 149 | switch (n) |
| 150 | { |
| 151 | case 0: |
| 152 | break; |
| 153 | |
| 154 | case 1: |
| 155 | *dst = *src; |
| 156 | break; |
| 157 | |
| 158 | case 2: |
| 159 | *(short *) dst = *(short *) src; |
| 160 | break; |
| 161 | |
| 162 | case 3: |
| 163 | *(short *) dst = *(short *) src; dst += 2; src += 2; |
| 164 | *dst = *src; |
| 165 | break; |
| 166 | |
| 167 | case 4: |
| 168 | *(long *) dst = *(long *) src; |
| 169 | break; |
| 170 | |
| 171 | case 5: |
| 172 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 173 | *dst = *src; |
| 174 | break; |
| 175 | |
| 176 | case 6: |
| 177 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 178 | *(short *) dst = *(short *) src; |
| 179 | break; |
| 180 | |
| 181 | case 7: |
| 182 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 183 | *(short *) dst = *(short *) src; dst += 2; src += 2; |
| 184 | *dst = *src; |
| 185 | break; |
| 186 | |
| 187 | case 8: |
| 188 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 189 | *(long *) dst = *(long *) src; |
| 190 | break; |
| 191 | |
| 192 | case 9: |
| 193 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 194 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 195 | *dst = *src; |
| 196 | break; |
| 197 | |
| 198 | case 10: |
| 199 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 200 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 201 | *(short *) dst = *(short *) src; |
| 202 | break; |
| 203 | |
| 204 | case 11: |
| 205 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 206 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 207 | *(short *) dst = *(short *) src; dst += 2; src += 2; |
| 208 | *dst = *src; |
| 209 | break; |
| 210 | |
| 211 | case 12: |
| 212 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 213 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 214 | *(long *) dst = *(long *) src; |
| 215 | break; |
| 216 | |
| 217 | case 13: |
| 218 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 219 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 220 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 221 | *dst = *src; |
| 222 | break; |
| 223 | |
| 224 | case 14: |
| 225 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 226 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 227 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 228 | *(short *) dst = *(short *) src; |
| 229 | break; |
| 230 | |
| 231 | case 15: |
| 232 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 233 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 234 | *(long *) dst = *(long *) src; dst += 4; src += 4; |
| 235 | *(short *) dst = *(short *) src; dst += 2; src += 2; |
| 236 | *dst = *src; |
| 237 | break; |
| 238 | } |
| 239 | |
| 240 | return return_dst; |
| 241 | } |
| 242 | libc_hidden_def(memcpy) |