zombie-lib/atoi.asm

51 lines
429 B
NASM

extern libz_strlen
global libz_atoi
section .text
libz_atoi:
; mov r11, rdi ;saveing it for later
push rdi
call libz_strlen
mov r9, rax
pop rdi
xor r10, r10
mov rcx, 1
add r9, rdi
dec r9
_loop:
xor rax, rax
mov al, [r9]
; 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
jmp _loop
_end:
mov rax, r10
ret