projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 | 1 | /* Copyright 2002 Andi Kleen, SuSE Labs */ |
| 8d379dad JB |
2 | |
| 3 | #include <linux/config.h> | |
| 4 | #include <linux/linkage.h> | |
| 5 | #include <asm/dwarf2.h> | |
| 6 | ||
| 1da177e4 LT |
7 | /* |
| 8 | * ISO C memset - set a memory block to a byte value. | |
| 9 | * | |
| 10 | * rdi destination | |
| 11 | * rsi value (char) | |
| 12 | * rdx count (bytes) | |
| 13 | * | |
| 14 | * rax original destination | |
| 15 | */ | |
| 8d379dad JB |
16 | ALIGN |
| 17 | memset_c: | |
| 18 | CFI_STARTPROC | |
| 19 | movq %rdi,%r9 | |
| 20 | movl %edx,%r8d | |
| 21 | andl $7,%r8d | |
| 22 | movl %edx,%ecx | |
| 23 | shrl $3,%ecx | |
| 24 | /* expand byte value */ | |
| 25 | movzbl %sil,%esi | |
| 26 | movabs $0x0101010101010101,%rax | |
| 27 | mulq %rsi /* with rax, clobbers rdx */ | |
| 28 | rep stosq | |
| 29 | movl %r8d,%ecx | |
| 30 | rep stosb | |
| 31 | movq %r9,%rax | |
| 32 | ret | |
| 33 | CFI_ENDPROC | |
| 34 | ENDPROC(memset_c) | |
| 35 | ||
| 36 | ENTRY(memset) | |
| 37 | ENTRY(__memset) | |
| 38 | CFI_STARTPROC | |
| 7bcd3f34 AK |
39 | movq %rdi,%r10 |
| 40 | movq %rdx,%r11 | |
| 41 | ||
| 42 | /* expand byte value */ | |
| 43 | movzbl %sil,%ecx | |
| 44 | movabs $0x0101010101010101,%rax | |
| 45 | mul %rcx /* with rax, clobbers rdx */ | |
| 46 | ||
| 47 | /* align dst */ | |
| 48 | movl %edi,%r9d | |
| 49 | andl $7,%r9d | |
| 50 | jnz .Lbad_alignment | |
| 8d379dad | 51 | CFI_REMEMBER_STATE |
| 7bcd3f34 AK |
52 | .Lafter_bad_alignment: |
| 53 | ||
| 54 | movl %r11d,%ecx | |
| 55 | shrl $6,%ecx | |
| 56 | jz .Lhandle_tail | |
| 57 | ||
| 58 | .p2align 4 | |
| 59 | .Lloop_64: | |
| 60 | decl %ecx | |
| 61 | movq %rax,(%rdi) | |
| 62 | movq %rax,8(%rdi) | |
| 63 | movq %rax,16(%rdi) | |
| 64 | movq %rax,24(%rdi) | |
| 65 | movq %rax,32(%rdi) | |
| 66 | movq %rax,40(%rdi) | |
| 67 | movq %rax,48(%rdi) | |
| 68 | movq %rax,56(%rdi) | |
| 69 | leaq 64(%rdi),%rdi | |
| 70 | jnz .Lloop_64 | |
| 71 | ||
| 72 | /* Handle tail in loops. The loops should be faster than hard | |
| 73 | to predict jump tables. */ | |
| 74 | .p2align 4 | |
| 75 | .Lhandle_tail: | |
| 76 | movl %r11d,%ecx | |
| 77 | andl $63&(~7),%ecx | |
| 78 | jz .Lhandle_7 | |
| 79 | shrl $3,%ecx | |
| 80 | .p2align 4 | |
| 81 | .Lloop_8: | |
| 82 | decl %ecx | |
| 83 | movq %rax,(%rdi) | |
| 84 | leaq 8(%rdi),%rdi | |
| 85 | jnz .Lloop_8 | |
| 86 | ||
| 87 | .Lhandle_7: | |
| 88 | movl %r11d,%ecx | |
| 89 | andl $7,%ecx | |
| 90 | jz .Lende | |
| 91 | .p2align 4 | |
| 92 | .Lloop_1: | |
| 93 | decl %ecx | |
| 94 | movb %al,(%rdi) | |
| 95 | leaq 1(%rdi),%rdi | |
| 96 | jnz .Lloop_1 | |
| 97 | ||
| 98 | .Lende: | |
| 99 | movq %r10,%rax | |
| 100 | ret | |
| 101 | ||
| 8d379dad | 102 | CFI_RESTORE_STATE |
| 7bcd3f34 AK |
103 | .Lbad_alignment: |
| 104 | cmpq $7,%r11 | |
| 105 | jbe .Lhandle_7 | |
| 106 | movq %rax,(%rdi) /* unaligned store */ | |
| 107 | movq $8,%r8 | |
| 108 | subq %r9,%r8 | |
| 109 | addq %r8,%rdi | |
| 110 | subq %r8,%r11 | |
| 111 | jmp .Lafter_bad_alignment | |
| 8d379dad JB |
112 | .Lfinal: |
| 113 | CFI_ENDPROC | |
| 114 | ENDPROC(memset) | |
| 115 | ENDPROC(__memset) | |
| 7bcd3f34 AK |
116 | |
| 117 | /* Some CPUs run faster using the string instructions. | |
| 118 | It is also a lot simpler. Use this when possible */ | |
| 119 | ||
| 120 | #include <asm/cpufeature.h> | |
| 121 | ||
| 8d379dad JB |
122 | .section .altinstr_replacement,"ax" |
| 123 | 1: .byte 0xeb /* jmp <disp8> */ | |
| 124 | .byte (memset_c - memset) - (2f - 1b) /* offset */ | |
| 125 | 2: | |
| 126 | .previous | |
| 7bcd3f34 AK |
127 | .section .altinstructions,"a" |
| 128 | .align 8 | |
| 8d379dad JB |
129 | .quad memset |
| 130 | .quad 1b | |
| 131 | .byte X86_FEATURE_REP_GOOD | |
| 132 | .byte .Lfinal - memset | |
| 133 | .byte 2b - 1b | |
| 7bcd3f34 | 134 | .previous |