ft_strdup.s

extern _ft_strlen
extern _ft_strcpy
extern ___error
extern _malloc

global _ft_strdup

section .text

_ft_strdup:
    mov r9, 0
    call _ft_strlen
    add rax, 1 ; add 1 the length of the string (for the terminating byte'\n')
    mov r10, rax ; move the contents of rax to r10 (strlen + 1)
    push rdi ; move the str (to be duplicate) to r11
    mov rdi, r10 ; move the length of str to rdi so malloc can use it
    call _malloc ; allocate as much bytes as we need to duplicate the str contained in r11
    cmp rax, 0   ; check that the poiner returned by malloc is not null
    je error
    pop rdi
    mov rsi, rdi
    mov rdi, rax ; mov the address of the alloced memory to rdi
    call _ft_strcpy ; call _ft_strcpy with rdi (dest) and rsi (src)
    ret

error:
    call ___error
    mov r8, 12
    mov [rax], r8
    mov rax, 0
    ret