Write X86/64 ALP to perform multiplication of two 8-bit hexadecimal numbers. Use add and shift method.(use of 64-bit registers is expected)

Flowchart of Multiplication Algorithm

     Example:
                 Using 4-bit numbers, perform the multiplication 9 × 12 (1001 × 1100).

                        

Step	Ax	Dx	Bx	Operation
0	0000 0000	1100	0000 1001	Initialization
1	0000 0000 0000 0000	1100 0110	0001 0010 0001 0010	Shift left B Shift right Q
2	0000 0000 0000 0000	0110 0011	0010 0100 0010 0100	Shift left B Shift right Q
3	0010 0100 0010 0100 0010 0100	0011  0011 0001	0010 0100 0100 1000 0100 1000	Add B to A Shift left B Shift right Q
4	0110 1100 0110 1100 0110 1100	0001  0001  0000	0100 1000 1001 0000 1001 0000	Add B to A  Shift left B Shift right Q

                                                    

64-bit nasm code

section .data

            innum1 db "Enter First 8 bit HEX no: ",10

            lennum1 equ $ -innum1

            innum2 db "Enter Second 8 bit HEX no: ",10

            lennum2 equ $ -innum2

            product db "Multiplication of two HEX no is: ",10

            productlen equ $ -product

section .bss

            num1 resb 3

            num2 resb 3

            result resb 4

%macro output 2                  ;macro for output

            mov rax,01h

            mov rdi,01h

            mov rsi,%1

            mov rdx,%2

            syscall

%endmacro

%macro input 2                    ;macro for input

            mov rax,00h

            mov rdi,00h

            mov rsi,%1

            mov rdx,%2

            syscall

%endmacro

section .text

global _start

 _start:

            output innum1,lennum1

            input num1,03

            output innum2,lennum2

            input num2,03

           

            mov rsi,num1

           call AtoH

           mov bx,ax

            mov rsi,num2

           call AtoH

           mov dx,ax

; Actual logic for multiplication of two numbers using add and shift method

                                                                

            xor ax,ax

            mov ch,08

again:

            bt dx,0   

            jnc skip1   

           add ax,bx   

skip1:   

           shl bx,1  

            shr dx,1

            dec ch

            jnz again

; logic to convert HEX to ASCII

            mov rsi,result

            mov ch,04

            mov cl,04

again1:

            rol ax,cl

            mov bl,al

            and bl,0fh

            cmp bl,09h

            jng skip2

            add bl,07h

skip2:

            add bl,30h

            mov [rsi],bl

            inc rsi

            dec ch

            jnz again1

            output product, productlen

            output result,04

mov rax,3ch

mov rdi,00

syscall

;procedure to convert ASCII to HEX

AtoH:

            xor ax,ax

            mov cl,04

            mov ch,02

up:

            cmp byte[rsi],39h

            jng down

            sub byte[rsi],07h

down:

            sub byte[rsi],30h

            shl ax,cl

            add al,[rsi]

            inc rsi

            dec ch

            jnz up

ret

Output:

[root@localhost ~]# nasm -f elf64 mul.asm

[root@localhost ~]# ld -o mul mul.o

[root@localhost ~]# ./mul

Enter First 8 bit HEX no: 15

Enter Second 8 bit HEX no: 12

Multiplication of two HEX no is: 017A