Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 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 | */ |
| 8 | #define _STRING_C |
| 9 | #include <linux/linkage.h> |
| 10 | #include <asm/dwarf2.h> |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 11 | #include <asm/cpufeature.h> |
Andy Lutomirski | 59e97e4 | 2011-07-13 09:24:10 -0400 | [diff] [blame] | 12 | #include <asm/alternative-asm.h> |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 13 | |
| 14 | #undef memmove |
| 15 | |
| 16 | /* |
| 17 | * Implement memmove(). This can handle overlap between src and dst. |
| 18 | * |
| 19 | * Input: |
| 20 | * rdi: dest |
| 21 | * rsi: src |
| 22 | * rdx: count |
| 23 | * |
| 24 | * Output: |
| 25 | * rax: dest |
| 26 | */ |
| 27 | ENTRY(memmove) |
| 28 | CFI_STARTPROC |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 29 | |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 30 | /* Handle more 32bytes in loop */ |
| 31 | mov %rdi, %rax |
| 32 | cmp $0x20, %rdx |
| 33 | jb 1f |
| 34 | |
| 35 | /* Decide forward/backward copy mode */ |
| 36 | cmp %rdi, %rsi |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 37 | jge .Lmemmove_begin_forward |
| 38 | mov %rsi, %r8 |
| 39 | add %rdx, %r8 |
| 40 | cmp %rdi, %r8 |
| 41 | jg 2f |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 42 | |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 43 | .Lmemmove_begin_forward: |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 44 | /* |
| 45 | * movsq instruction have many startup latency |
| 46 | * so we handle small size by general register. |
| 47 | */ |
| 48 | cmp $680, %rdx |
| 49 | jb 3f |
| 50 | /* |
| 51 | * movsq instruction is only good for aligned case. |
| 52 | */ |
| 53 | |
| 54 | cmpb %dil, %sil |
| 55 | je 4f |
| 56 | 3: |
| 57 | sub $0x20, %rdx |
| 58 | /* |
Andy Shevchenko | bb916ff | 2013-04-15 12:06:09 +0300 | [diff] [blame^] | 59 | * We gobble 32 bytes forward in each loop. |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 60 | */ |
| 61 | 5: |
| 62 | sub $0x20, %rdx |
| 63 | movq 0*8(%rsi), %r11 |
| 64 | movq 1*8(%rsi), %r10 |
| 65 | movq 2*8(%rsi), %r9 |
| 66 | movq 3*8(%rsi), %r8 |
| 67 | leaq 4*8(%rsi), %rsi |
| 68 | |
| 69 | movq %r11, 0*8(%rdi) |
| 70 | movq %r10, 1*8(%rdi) |
| 71 | movq %r9, 2*8(%rdi) |
| 72 | movq %r8, 3*8(%rdi) |
| 73 | leaq 4*8(%rdi), %rdi |
| 74 | jae 5b |
| 75 | addq $0x20, %rdx |
| 76 | jmp 1f |
| 77 | /* |
| 78 | * Handle data forward by movsq. |
| 79 | */ |
| 80 | .p2align 4 |
| 81 | 4: |
| 82 | movq %rdx, %rcx |
| 83 | movq -8(%rsi, %rdx), %r11 |
| 84 | lea -8(%rdi, %rdx), %r10 |
| 85 | shrq $3, %rcx |
| 86 | rep movsq |
| 87 | movq %r11, (%r10) |
| 88 | jmp 13f |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 89 | .Lmemmove_end_forward: |
| 90 | |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 91 | /* |
| 92 | * Handle data backward by movsq. |
| 93 | */ |
| 94 | .p2align 4 |
| 95 | 7: |
| 96 | movq %rdx, %rcx |
| 97 | movq (%rsi), %r11 |
| 98 | movq %rdi, %r10 |
| 99 | leaq -8(%rsi, %rdx), %rsi |
| 100 | leaq -8(%rdi, %rdx), %rdi |
| 101 | shrq $3, %rcx |
| 102 | std |
| 103 | rep movsq |
| 104 | cld |
| 105 | movq %r11, (%r10) |
| 106 | jmp 13f |
| 107 | |
| 108 | /* |
| 109 | * Start to prepare for backward copy. |
| 110 | */ |
| 111 | .p2align 4 |
| 112 | 2: |
| 113 | cmp $680, %rdx |
| 114 | jb 6f |
| 115 | cmp %dil, %sil |
| 116 | je 7b |
| 117 | 6: |
| 118 | /* |
| 119 | * Calculate copy position to tail. |
| 120 | */ |
| 121 | addq %rdx, %rsi |
| 122 | addq %rdx, %rdi |
| 123 | subq $0x20, %rdx |
| 124 | /* |
Andy Shevchenko | bb916ff | 2013-04-15 12:06:09 +0300 | [diff] [blame^] | 125 | * We gobble 32 bytes backward in each loop. |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 126 | */ |
| 127 | 8: |
| 128 | subq $0x20, %rdx |
| 129 | movq -1*8(%rsi), %r11 |
| 130 | movq -2*8(%rsi), %r10 |
| 131 | movq -3*8(%rsi), %r9 |
| 132 | movq -4*8(%rsi), %r8 |
| 133 | leaq -4*8(%rsi), %rsi |
| 134 | |
| 135 | movq %r11, -1*8(%rdi) |
| 136 | movq %r10, -2*8(%rdi) |
| 137 | movq %r9, -3*8(%rdi) |
| 138 | movq %r8, -4*8(%rdi) |
| 139 | leaq -4*8(%rdi), %rdi |
| 140 | jae 8b |
| 141 | /* |
| 142 | * Calculate copy position to head. |
| 143 | */ |
| 144 | addq $0x20, %rdx |
| 145 | subq %rdx, %rsi |
| 146 | subq %rdx, %rdi |
| 147 | 1: |
| 148 | cmpq $16, %rdx |
| 149 | jb 9f |
| 150 | /* |
| 151 | * Move data from 16 bytes to 31 bytes. |
| 152 | */ |
| 153 | movq 0*8(%rsi), %r11 |
| 154 | movq 1*8(%rsi), %r10 |
| 155 | movq -2*8(%rsi, %rdx), %r9 |
| 156 | movq -1*8(%rsi, %rdx), %r8 |
| 157 | movq %r11, 0*8(%rdi) |
| 158 | movq %r10, 1*8(%rdi) |
| 159 | movq %r9, -2*8(%rdi, %rdx) |
| 160 | movq %r8, -1*8(%rdi, %rdx) |
| 161 | jmp 13f |
| 162 | .p2align 4 |
| 163 | 9: |
| 164 | cmpq $8, %rdx |
| 165 | jb 10f |
| 166 | /* |
| 167 | * Move data from 8 bytes to 15 bytes. |
| 168 | */ |
| 169 | movq 0*8(%rsi), %r11 |
| 170 | movq -1*8(%rsi, %rdx), %r10 |
| 171 | movq %r11, 0*8(%rdi) |
| 172 | movq %r10, -1*8(%rdi, %rdx) |
| 173 | jmp 13f |
| 174 | 10: |
| 175 | cmpq $4, %rdx |
| 176 | jb 11f |
| 177 | /* |
| 178 | * Move data from 4 bytes to 7 bytes. |
| 179 | */ |
| 180 | movl (%rsi), %r11d |
| 181 | movl -4(%rsi, %rdx), %r10d |
| 182 | movl %r11d, (%rdi) |
| 183 | movl %r10d, -4(%rdi, %rdx) |
| 184 | jmp 13f |
| 185 | 11: |
| 186 | cmp $2, %rdx |
| 187 | jb 12f |
| 188 | /* |
| 189 | * Move data from 2 bytes to 3 bytes. |
| 190 | */ |
| 191 | movw (%rsi), %r11w |
| 192 | movw -2(%rsi, %rdx), %r10w |
| 193 | movw %r11w, (%rdi) |
| 194 | movw %r10w, -2(%rdi, %rdx) |
| 195 | jmp 13f |
| 196 | 12: |
| 197 | cmp $1, %rdx |
| 198 | jb 13f |
| 199 | /* |
| 200 | * Move data for 1 byte. |
| 201 | */ |
| 202 | movb (%rsi), %r11b |
| 203 | movb %r11b, (%rdi) |
| 204 | 13: |
| 205 | retq |
| 206 | CFI_ENDPROC |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 207 | |
| 208 | .section .altinstr_replacement,"ax" |
| 209 | .Lmemmove_begin_forward_efs: |
| 210 | /* Forward moving data. */ |
| 211 | movq %rdx, %rcx |
| 212 | rep movsb |
| 213 | retq |
| 214 | .Lmemmove_end_forward_efs: |
| 215 | .previous |
| 216 | |
| 217 | .section .altinstructions,"a" |
Andy Lutomirski | 59e97e4 | 2011-07-13 09:24:10 -0400 | [diff] [blame] | 218 | altinstruction_entry .Lmemmove_begin_forward, \ |
| 219 | .Lmemmove_begin_forward_efs,X86_FEATURE_ERMS, \ |
| 220 | .Lmemmove_end_forward-.Lmemmove_begin_forward, \ |
| 221 | .Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs |
Fenghua Yu | 057e05c | 2011-05-17 15:29:17 -0700 | [diff] [blame] | 222 | .previous |
Fenghua Yu | 9599ec0 | 2011-01-17 17:39:15 -0800 | [diff] [blame] | 223 | ENDPROC(memmove) |