; THIS CODE HAS NOT BEEN TESTED AND IS NOT FULLY OPERATIONAL.

; Problem Statement: Write X86/64 ALP to perform multiplication of two 8-bit hexadecimal numbers. Using successive addition method. (Use of 64-bit registers is expected).

; Code from Microprocessor (SPPU - Second Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-se-comp-content/Microprocessor/


; BEGINNING OF CODE
%macro print 2
mov rax,1
mov rdi,1
mov rsi,%1
mov rdx,%2
syscall
%endmacro

%macro accept 2
mov rax,0
mov rdi,0
mov rsi,%1
mov rdx,%2
syscall
%endmacro

section .data

m1 db 10,"----- Multiplication using successive addition -----",10,13
l1 equ $-m1

m2 db 10,"Enter the multiplicand",10,13
l2 equ $-m2

m3 db 10,"Enter the multiplier",10,13
l3 equ $-m3

res db 10,"Multiplication of the numbers is::",10,13
rlen equ $-res


section .bss

numascii resb 03
mplier resq 02
mcand resq 02
;result resq 01
dispbuff resb 04

section .txt
global _start:
_start:

print m1,l1

print m2,l2
accept numascii,3
call packnum
mov byte[mcand],bl

print m3,l3
accept numascii,3
call packnum
mov byte[mplier],bl

print res,rlen

	mov rax,0
	cmp qword[mplier],0
	jz ll5
	
ll1:
	add rax,qword[mcand]
	dec qword[mplier]
	jnz ll1

ll5:
	call dispnum
	
exit:
	mov rax,60
	mov rbx,00
	syscall


dispnum:
	mov rbx,rax
	mov rcx,04
	mov rdi,dispbuff
	up2:
	rol bx,4
	mov al,bl
	and al,0fh
	cmp al,09
	jbe dskip
	add al,07h
dskip:
	add al,30h
	mov [rdi],al
	inc rdi
	loop up2
	print dispbuff,4
	ret


packnum:
	mov bl,0
	mov rcx,2
	mov rsi,numascii
	up1:
		rol bl,04
		mov al,[rsi]
		cmp al,39h
		jbe skip1
		sub al,07h
	skip1:
		sub al,30h
		add bl,al
		inc rsi
		loop up1
	ret