projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 9599ec04 FY |
1 | /* |
| 2 | * Normally compiler builtins are used, but sometimes the compiler calls out | |
| 3 | * of line code. Based on asm-i386/string.h. | |
| 4 | * | |
| 5 | * This assembly file is re-written from memmove_64.c file. | |
| 6 | * - Copyright 2011 Fenghua Yu <fenghua.yu@intel.com> | |
| 7 | */ | |
| 9599ec04 | 8 | #include <linux/linkage.h> |
| cd4d09ec | 9 | #include <asm/cpufeatures.h> |
| 59e97e4d | 10 | #include <asm/alternative-asm.h> |
| 784d5699 | 11 | #include <asm/export.h> |
| 9599ec04 FY |
12 | |
| 13 | #undef memmove | |
| 14 | ||
| 15 | /* | |
| 16 | * Implement memmove(). This can handle overlap between src and dst. | |
| 17 | * | |
| 18 | * Input: | |
| 19 | * rdi: dest | |
| 20 | * rsi: src | |
| 21 | * rdx: count | |
| 22 | * | |
| 23 | * Output: | |
| 24 | * rax: dest | |
| 25 | */ | |
| 393f203f AR |
26 | .weak memmove |
| 27 | ||
| 9599ec04 | 28 | ENTRY(memmove) |
| 393f203f | 29 | ENTRY(__memmove) |
| 057e05c1 | 30 | |
| d50ba368 | 31 | /* Handle more 32 bytes in loop */ |
| 9599ec04 FY |
32 | mov %rdi, %rax |
| 33 | cmp $0x20, %rdx | |
| 34 | jb 1f | |
| 35 | ||
| 36 | /* Decide forward/backward copy mode */ | |
| 37 | cmp %rdi, %rsi | |
| 057e05c1 FY |
38 | jge .Lmemmove_begin_forward |
| 39 | mov %rsi, %r8 | |
| 40 | add %rdx, %r8 | |
| 41 | cmp %rdi, %r8 | |
| 42 | jg 2f | |
| 9599ec04 | 43 | |
| 057e05c1 | 44 | .Lmemmove_begin_forward: |
| a77600cd BP |
45 | ALTERNATIVE "", "movq %rdx, %rcx; rep movsb; retq", X86_FEATURE_ERMS |
| 46 | ||
| 9599ec04 FY |
47 | /* |
| 48 | * movsq instruction have many startup latency | |
| 49 | * so we handle small size by general register. | |
| 50 | */ | |
| 51 | cmp $680, %rdx | |
| 52 | jb 3f | |
| 53 | /* | |
| 54 | * movsq instruction is only good for aligned case. | |
| 55 | */ | |
| 56 | ||
| 57 | cmpb %dil, %sil | |
| 58 | je 4f | |
| 59 | 3: | |
| 60 | sub $0x20, %rdx | |
| 61 | /* | |
| bb916ff7 | 62 | * We gobble 32 bytes forward in each loop. |
| 9599ec04 FY |
63 | */ |
| 64 | 5: | |
| 65 | sub $0x20, %rdx | |
| 66 | movq 0*8(%rsi), %r11 | |
| 67 | movq 1*8(%rsi), %r10 | |
| 68 | movq 2*8(%rsi), %r9 | |
| 69 | movq 3*8(%rsi), %r8 | |
| 70 | leaq 4*8(%rsi), %rsi | |
| 71 | ||
| 72 | movq %r11, 0*8(%rdi) | |
| 73 | movq %r10, 1*8(%rdi) | |
| 74 | movq %r9, 2*8(%rdi) | |
| 75 | movq %r8, 3*8(%rdi) | |
| 76 | leaq 4*8(%rdi), %rdi | |
| 77 | jae 5b | |
| 78 | addq $0x20, %rdx | |
| 79 | jmp 1f | |
| 80 | /* | |
| 81 | * Handle data forward by movsq. | |
| 82 | */ | |
| 83 | .p2align 4 | |
| 84 | 4: | |
| 85 | movq %rdx, %rcx | |
| 86 | movq -8(%rsi, %rdx), %r11 | |
| 87 | lea -8(%rdi, %rdx), %r10 | |
| 88 | shrq $3, %rcx | |
| 89 | rep movsq | |
| 90 | movq %r11, (%r10) | |
| 91 | jmp 13f | |
| 057e05c1 FY |
92 | .Lmemmove_end_forward: |
| 93 | ||
| 9599ec04 FY |
94 | /* |
| 95 | * Handle data backward by movsq. | |
| 96 | */ | |
| 97 | .p2align 4 | |
| 98 | 7: | |
| 99 | movq %rdx, %rcx | |
| 100 | movq (%rsi), %r11 | |
| 101 | movq %rdi, %r10 | |
| 102 | leaq -8(%rsi, %rdx), %rsi | |
| 103 | leaq -8(%rdi, %rdx), %rdi | |
| 104 | shrq $3, %rcx | |
| 105 | std | |
| 106 | rep movsq | |
| 107 | cld | |
| 108 | movq %r11, (%r10) | |
| 109 | jmp 13f | |
| 110 | ||
| 111 | /* | |
| 112 | * Start to prepare for backward copy. | |
| 113 | */ | |
| 114 | .p2align 4 | |
| 115 | 2: | |
| 116 | cmp $680, %rdx | |
| 117 | jb 6f | |
| 118 | cmp %dil, %sil | |
| 119 | je 7b | |
| 120 | 6: | |
| 121 | /* | |
| 122 | * Calculate copy position to tail. | |
| 123 | */ | |
| 124 | addq %rdx, %rsi | |
| 125 | addq %rdx, %rdi | |
| 126 | subq $0x20, %rdx | |
| 127 | /* | |
| bb916ff7 | 128 | * We gobble 32 bytes backward in each loop. |
| 9599ec04 FY |
129 | */ |
| 130 | 8: | |
| 131 | subq $0x20, %rdx | |
| 132 | movq -1*8(%rsi), %r11 | |
| 133 | movq -2*8(%rsi), %r10 | |
| 134 | movq -3*8(%rsi), %r9 | |
| 135 | movq -4*8(%rsi), %r8 | |
| 136 | leaq -4*8(%rsi), %rsi | |
| 137 | ||
| 138 | movq %r11, -1*8(%rdi) | |
| 139 | movq %r10, -2*8(%rdi) | |
| 140 | movq %r9, -3*8(%rdi) | |
| 141 | movq %r8, -4*8(%rdi) | |
| 142 | leaq -4*8(%rdi), %rdi | |
| 143 | jae 8b | |
| 144 | /* | |
| 145 | * Calculate copy position to head. | |
| 146 | */ | |
| 147 | addq $0x20, %rdx | |
| 148 | subq %rdx, %rsi | |
| 149 | subq %rdx, %rdi | |
| 150 | 1: | |
| 151 | cmpq $16, %rdx | |
| 152 | jb 9f | |
| 153 | /* | |
| 154 | * Move data from 16 bytes to 31 bytes. | |
| 155 | */ | |
| 156 | movq 0*8(%rsi), %r11 | |
| 157 | movq 1*8(%rsi), %r10 | |
| 158 | movq -2*8(%rsi, %rdx), %r9 | |
| 159 | movq -1*8(%rsi, %rdx), %r8 | |
| 160 | movq %r11, 0*8(%rdi) | |
| 161 | movq %r10, 1*8(%rdi) | |
| 162 | movq %r9, -2*8(%rdi, %rdx) | |
| 163 | movq %r8, -1*8(%rdi, %rdx) | |
| 164 | jmp 13f | |
| 165 | .p2align 4 | |
| 166 | 9: | |
| 167 | cmpq $8, %rdx | |
| 168 | jb 10f | |
| 169 | /* | |
| 170 | * Move data from 8 bytes to 15 bytes. | |
| 171 | */ | |
| 172 | movq 0*8(%rsi), %r11 | |
| 173 | movq -1*8(%rsi, %rdx), %r10 | |
| 174 | movq %r11, 0*8(%rdi) | |
| 175 | movq %r10, -1*8(%rdi, %rdx) | |
| 176 | jmp 13f | |
| 177 | 10: | |
| 178 | cmpq $4, %rdx | |
| 179 | jb 11f | |
| 180 | /* | |
| 181 | * Move data from 4 bytes to 7 bytes. | |
| 182 | */ | |
| 183 | movl (%rsi), %r11d | |
| 184 | movl -4(%rsi, %rdx), %r10d | |
| 185 | movl %r11d, (%rdi) | |
| 186 | movl %r10d, -4(%rdi, %rdx) | |
| 187 | jmp 13f | |
| 188 | 11: | |
| 189 | cmp $2, %rdx | |
| 190 | jb 12f | |
| 191 | /* | |
| 192 | * Move data from 2 bytes to 3 bytes. | |
| 193 | */ | |
| 194 | movw (%rsi), %r11w | |
| 195 | movw -2(%rsi, %rdx), %r10w | |
| 196 | movw %r11w, (%rdi) | |
| 197 | movw %r10w, -2(%rdi, %rdx) | |
| 198 | jmp 13f | |
| 199 | 12: | |
| 200 | cmp $1, %rdx | |
| 201 | jb 13f | |
| 202 | /* | |
| 203 | * Move data for 1 byte. | |
| 204 | */ | |
| 205 | movb (%rsi), %r11b | |
| 206 | movb %r11b, (%rdi) | |
| 207 | 13: | |
| 208 | retq | |
| 393f203f | 209 | ENDPROC(__memmove) |
| 9599ec04 | 210 | ENDPROC(memmove) |
| 784d5699 AV |
211 | EXPORT_SYMBOL(__memmove) |
| 212 | EXPORT_SYMBOL(memmove) |