forked from Bananymous/banan-os
63 lines
856 B
ArmAsm
63 lines
856 B
ArmAsm
.global memchr
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memchr:
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movb %sil, %al
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movq %rdx, %rcx
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movq $1, %rdx
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cmpq $1, %rcx # clear ZF if count is zero
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repne scasb
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cmoveq %rdi, %rdx
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leaq -1(%rdx), %rax
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ret
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.global memcmp
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memcmp:
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movq %rdx, %rcx
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testq %rcx, %rcx # set ZF if count is zero
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repe cmpsb
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jne .memcmp_not_equal
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xorq %rax, %rax
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ret
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.memcmp_not_equal:
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movzbl -1(%rdi), %eax
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movzbl -1(%rsi), %ecx
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subq %rcx, %rax
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ret
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.global memcpy
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memcpy:
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movq %rdi, %rax
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movq %rdx, %rcx
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rep movsb
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ret
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.global memmove
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memmove:
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cmpq %rdi, %rsi
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jae memcpy
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movq %rdi, %rax
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leaq -1(%rdi, %rdx), %rdi
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leaq -1(%rsi, %rdx), %rsi
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movq %rdx, %rcx
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std
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rep movsb
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cld
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ret
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.global memset
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memset:
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movq %rdi, %r8
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movb %sil, %al
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movq %rdx, %rcx
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rep stosb
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movq %r8, %rax
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ret
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.global strlen
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strlen:
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xorb %al, %al
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movq $-1, %rcx
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repne scasb
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movq $-2, %rax
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subq %rcx, %rax
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ret
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