extern libz_strlen

global libz_hextoi

section .text

libz_hextoi:


;	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]

	cmp rax, 48
	jb _nan
	cmp rax, 70 ;if its not a number then return 0 then exit
	ja _nan		;this actually as a bug if you put a : it will be allowed

;	push rax

	cmp rax, 58 ;if(char < 58){sub char, 48}else{sub char, 55}
	jb _charbelow
	sub rax, 55
	jmp _hexitif
_charbelow:
	sub rax, 48
_hexitif:
    	
	mul rcx
	add r10, rax
;	pop rax

	cmp r9, rdi
	je _end
	dec r9
;	push rax
	mov rax, 16
	mul rcx
	mov rcx, rax
;	pop rax

	jmp _loop

_nan:
	xor r10, r10

_end:
	mov rax, r10
	ret