zombie-lib/atoi.asm

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429 B
NASM
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extern libz_strlen
global libz_atoi
section .text
libz_atoi:
; mov r11, rdi ;saveing it for later
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push rdi
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call libz_strlen
mov r9, rax
pop rdi
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xor r10, r10
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mov rcx, 1
add r9, rdi
dec r9
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_loop:
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xor rax, rax
mov al, [r9]
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; push rax
sub rax, 48
mul rcx
add r10, rax
; pop rax
cmp r9, rdi
je _end
dec r9
; push rax
mov rax, 10
mul rcx
mov rcx, rax
; pop rax
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jmp _loop
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_end:
mov rax, r10
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ret