banan-os/userspace/libraries/LibC/arch/x86_64/string.S

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.global memchr
memchr:
movb %sil, %al
movq %rdx, %rcx
repne scasb
xorq %rax, %rax
testq %rcx, %rcx
cmovnzq %rdi, %rax
ret
.global memcmp
memcmp:
movq %rdx, %rcx
repe cmpsb
jne .memcmp_not_equal
xorq %rax, %rax
ret
.memcmp_not_equal:
movzbl -1(%rdi), %eax
movzbl -1(%rsi), %ecx
subq %rcx, %rax
ret
.global memcpy
memcpy:
movq %rdi, %rax
movq %rdx, %rcx
movq %rdi, %rdx
rep movsb
movq %rdx, %rax
ret
.global memmove
memmove:
cmpq %rdi, %rsi
jae memcpy
leaq -1(%rdi, %rdx), %rdi
leaq -1(%rsi, %rdx), %rsi
movq %rdx, %rcx
std
rep movsb
cld
leaq 1(%rdi), %rax
ret
.global memset
memset:
movq %rdi, %r8
movb %sil, %al
movq %rdx, %rcx
rep stosb
movq %r8, %rax
ret
.global strlen
strlen:
xorb %al, %al
movq $-1, %rcx
repne scasb
movq $-2, %rax
subq %rcx, %rax
ret