122 lines
1.6 KiB
ArmAsm
122 lines
1.6 KiB
ArmAsm
/* Copyright 2002 Andi Kleen */
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#include <asm/cpufeature.h>
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/*
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* memcpy - Copy a memory block.
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*
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* Input:
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* rdi destination
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* rsi source
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* rdx count
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*
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* Output:
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* rax original destination
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*/
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.globl __memcpy
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.globl memcpy
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.p2align 4
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__memcpy:
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memcpy:
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pushq %rbx
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movq %rdi,%rax
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movl %edx,%ecx
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shrl $6,%ecx
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jz .Lhandle_tail
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.p2align 4
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.Lloop_64:
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decl %ecx
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movq (%rsi),%r11
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movq 8(%rsi),%r8
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movq %r11,(%rdi)
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movq %r8,1*8(%rdi)
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movq 2*8(%rsi),%r9
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movq 3*8(%rsi),%r10
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movq %r9,2*8(%rdi)
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movq %r10,3*8(%rdi)
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movq 4*8(%rsi),%r11
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movq 5*8(%rsi),%r8
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movq %r11,4*8(%rdi)
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movq %r8,5*8(%rdi)
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movq 6*8(%rsi),%r9
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movq 7*8(%rsi),%r10
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movq %r9,6*8(%rdi)
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movq %r10,7*8(%rdi)
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leaq 64(%rsi),%rsi
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leaq 64(%rdi),%rdi
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jnz .Lloop_64
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.Lhandle_tail:
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movl %edx,%ecx
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andl $63,%ecx
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shrl $3,%ecx
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jz .Lhandle_7
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.p2align 4
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.Lloop_8:
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decl %ecx
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movq (%rsi),%r8
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movq %r8,(%rdi)
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leaq 8(%rdi),%rdi
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leaq 8(%rsi),%rsi
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jnz .Lloop_8
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.Lhandle_7:
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movl %edx,%ecx
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andl $7,%ecx
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jz .Lende
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.p2align 4
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.Lloop_1:
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movb (%rsi),%r8b
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movb %r8b,(%rdi)
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incq %rdi
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incq %rsi
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decl %ecx
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jnz .Lloop_1
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.Lende:
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popq %rbx
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ret
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.Lfinal:
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/* Some CPUs run faster using the string copy instructions.
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It is also a lot simpler. Use this when possible */
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.section .altinstructions,"a"
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.align 8
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.quad memcpy
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.quad memcpy_c
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.byte X86_FEATURE_REP_GOOD
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.byte .Lfinal-memcpy
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.byte memcpy_c_end-memcpy_c
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.previous
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.section .altinstr_replacement,"ax"
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/* rdi destination
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* rsi source
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* rdx count
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*/
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memcpy_c:
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movq %rdi,%rax
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movl %edx,%ecx
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shrl $3,%ecx
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andl $7,%edx
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rep
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movsq
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movl %edx,%ecx
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rep
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movsb
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ret
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memcpy_c_end:
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.previous
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