| Gabe Black | ccdc005 | 2013-07-07 14:08:30 -0700 | [diff] [blame] | 1 | #include <string.h> |
| 2 | |
| 3 | void *memmove(void *dest, const void *src, size_t n) |
| 4 | { |
| 5 | int d0,d1,d2,d3,d4,d5; |
| 6 | char *ret = dest; |
| 7 | |
| 8 | __asm__ __volatile__( |
| 9 | /* Handle more 16bytes in loop */ |
| 10 | "cmp $0x10, %0\n\t" |
| 11 | "jb 1f\n\t" |
| 12 | |
| 13 | /* Decide forward/backward copy mode */ |
| 14 | "cmp %2, %1\n\t" |
| 15 | "jb 2f\n\t" |
| 16 | |
| 17 | /* |
| 18 | * movs instruction have many startup latency |
| 19 | * so we handle small size by general register. |
| 20 | */ |
| 21 | "cmp $680, %0\n\t" |
| 22 | "jb 3f\n\t" |
| 23 | /* |
| 24 | * movs instruction is only good for aligned case. |
| 25 | */ |
| 26 | "mov %1, %3\n\t" |
| 27 | "xor %2, %3\n\t" |
| 28 | "and $0xff, %3\n\t" |
| 29 | "jz 4f\n\t" |
| 30 | "3:\n\t" |
| 31 | "sub $0x10, %0\n\t" |
| 32 | |
| 33 | /* |
| 34 | * We gobble 16byts forward in each loop. |
| 35 | */ |
| 36 | "3:\n\t" |
| 37 | "sub $0x10, %0\n\t" |
| 38 | "mov 0*4(%1), %3\n\t" |
| 39 | "mov 1*4(%1), %4\n\t" |
| 40 | "mov %3, 0*4(%2)\n\t" |
| 41 | "mov %4, 1*4(%2)\n\t" |
| 42 | "mov 2*4(%1), %3\n\t" |
| 43 | "mov 3*4(%1), %4\n\t" |
| 44 | "mov %3, 2*4(%2)\n\t" |
| 45 | "mov %4, 3*4(%2)\n\t" |
| 46 | "lea 0x10(%1), %1\n\t" |
| 47 | "lea 0x10(%2), %2\n\t" |
| 48 | "jae 3b\n\t" |
| 49 | "add $0x10, %0\n\t" |
| 50 | "jmp 1f\n\t" |
| 51 | |
| 52 | /* |
| 53 | * Handle data forward by movs. |
| 54 | */ |
| 55 | ".p2align 4\n\t" |
| 56 | "4:\n\t" |
| 57 | "mov -4(%1, %0), %3\n\t" |
| 58 | "lea -4(%2, %0), %4\n\t" |
| 59 | "shr $2, %0\n\t" |
| 60 | "rep movsl\n\t" |
| 61 | "mov %3, (%4)\n\t" |
| 62 | "jmp 11f\n\t" |
| 63 | /* |
| 64 | * Handle data backward by movs. |
| 65 | */ |
| 66 | ".p2align 4\n\t" |
| 67 | "6:\n\t" |
| 68 | "mov (%1), %3\n\t" |
| 69 | "mov %2, %4\n\t" |
| 70 | "lea -4(%1, %0), %1\n\t" |
| 71 | "lea -4(%2, %0), %2\n\t" |
| 72 | "shr $2, %0\n\t" |
| 73 | "std\n\t" |
| 74 | "rep movsl\n\t" |
| 75 | "mov %3,(%4)\n\t" |
| 76 | "cld\n\t" |
| 77 | "jmp 11f\n\t" |
| 78 | |
| 79 | /* |
| 80 | * Start to prepare for backward copy. |
| 81 | */ |
| 82 | ".p2align 4\n\t" |
| 83 | "2:\n\t" |
| 84 | "cmp $680, %0\n\t" |
| 85 | "jb 5f\n\t" |
| 86 | "mov %1, %3\n\t" |
| 87 | "xor %2, %3\n\t" |
| 88 | "and $0xff, %3\n\t" |
| 89 | "jz 6b\n\t" |
| 90 | |
| 91 | /* |
| 92 | * Calculate copy position to tail. |
| 93 | */ |
| 94 | "5:\n\t" |
| 95 | "add %0, %1\n\t" |
| 96 | "add %0, %2\n\t" |
| 97 | "sub $0x10, %0\n\t" |
| 98 | |
| 99 | /* |
| 100 | * We gobble 16byts backward in each loop. |
| 101 | */ |
| 102 | "7:\n\t" |
| 103 | "sub $0x10, %0\n\t" |
| 104 | |
| 105 | "mov -1*4(%1), %3\n\t" |
| 106 | "mov -2*4(%1), %4\n\t" |
| 107 | "mov %3, -1*4(%2)\n\t" |
| 108 | "mov %4, -2*4(%2)\n\t" |
| 109 | "mov -3*4(%1), %3\n\t" |
| 110 | "mov -4*4(%1), %4\n\t" |
| 111 | "mov %3, -3*4(%2)\n\t" |
| 112 | "mov %4, -4*4(%2)\n\t" |
| 113 | "lea -0x10(%1), %1\n\t" |
| 114 | "lea -0x10(%2), %2\n\t" |
| 115 | "jae 7b\n\t" |
| 116 | /* |
| 117 | * Calculate copy position to head. |
| 118 | */ |
| 119 | "add $0x10, %0\n\t" |
| 120 | "sub %0, %1\n\t" |
| 121 | "sub %0, %2\n\t" |
| 122 | |
| 123 | /* |
| 124 | * Move data from 8 bytes to 15 bytes. |
| 125 | */ |
| 126 | ".p2align 4\n\t" |
| 127 | "1:\n\t" |
| 128 | "cmp $8, %0\n\t" |
| 129 | "jb 8f\n\t" |
| 130 | "mov 0*4(%1), %3\n\t" |
| 131 | "mov 1*4(%1), %4\n\t" |
| 132 | "mov -2*4(%1, %0), %5\n\t" |
| 133 | "mov -1*4(%1, %0), %1\n\t" |
| 134 | |
| 135 | "mov %3, 0*4(%2)\n\t" |
| 136 | "mov %4, 1*4(%2)\n\t" |
| 137 | "mov %5, -2*4(%2, %0)\n\t" |
| 138 | "mov %1, -1*4(%2, %0)\n\t" |
| 139 | "jmp 11f\n\t" |
| 140 | |
| 141 | /* |
| 142 | * Move data from 4 bytes to 7 bytes. |
| 143 | */ |
| 144 | ".p2align 4\n\t" |
| 145 | "8:\n\t" |
| 146 | "cmp $4, %0\n\t" |
| 147 | "jb 9f\n\t" |
| 148 | "mov 0*4(%1), %3\n\t" |
| 149 | "mov -1*4(%1, %0), %4\n\t" |
| 150 | "mov %3, 0*4(%2)\n\t" |
| 151 | "mov %4, -1*4(%2, %0)\n\t" |
| 152 | "jmp 11f\n\t" |
| 153 | |
| 154 | /* |
| 155 | * Move data from 2 bytes to 3 bytes. |
| 156 | */ |
| 157 | ".p2align 4\n\t" |
| 158 | "9:\n\t" |
| 159 | "cmp $2, %0\n\t" |
| 160 | "jb 10f\n\t" |
| 161 | "movw 0*2(%1), %%dx\n\t" |
| 162 | "movw -1*2(%1, %0), %%bx\n\t" |
| 163 | "movw %%dx, 0*2(%2)\n\t" |
| 164 | "movw %%bx, -1*2(%2, %0)\n\t" |
| 165 | "jmp 11f\n\t" |
| 166 | |
| 167 | /* |
| 168 | * Move data for 1 byte. |
| 169 | */ |
| 170 | ".p2align 4\n\t" |
| 171 | "10:\n\t" |
| 172 | "cmp $1, %0\n\t" |
| 173 | "jb 11f\n\t" |
| 174 | "movb (%1), %%cl\n\t" |
| 175 | "movb %%cl, (%2)\n\t" |
| 176 | ".p2align 4\n\t" |
| 177 | "11:" |
| 178 | : "=&c" (d0), "=&S" (d1), "=&D" (d2), |
| 179 | "=r" (d3),"=r" (d4), "=r"(d5) |
| 180 | :"0" (n), |
| 181 | "1" (src), |
| 182 | "2" (dest) |
| 183 | :"memory"); |
| 184 | |
| 185 | return ret; |
| 186 | |
| 187 | } |