Multiplication of two 8-bit hexadecimal numbers (Assembly x64)
section .data msg db 10,13,”Which operation to perform:1.Successive Addition2.Add and rotate left3.Exit” msglen equ $-msg msg1 db 10,13,”Enter first 4 digit hexadecimal no:” msg1len equ $-msg1 msg2 db 10,13,”Enter second 4 digit hexadecimal no:” msg2len equ $-msg2 msg3 db 10,13,”Result by first method is:” msg3len equ $-msg3 msg4 db 10,13,”Result by second method is:” msg4len equ $-msg4 section .bss choice resb 2 abc resb 8 %macro display 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 num1 resb 5 num2 resb 5 cnt resb 1 num resb 5 number resb 4 section .text global _start _start: display msg,msglen accept choice,2 mov al,[choice] sub al,30h cmp al,01 je successive_addition cmp al,02 je add_rol cmp al,03 je exit successive_addition: display msg1,msg1len accept num,5 call ascii_original mov [num1],rbx display msg2,msg2len accept num,5 call ascii_original mov [num2],rbx mov rbx,0 mov rax,0 ;used for sum variable mov rdx,0 ;used for carry mov rbx,[num1] mov rcx,[num2] l11: add rax,rbx jnc l12 inc rdx ;ie carry=carry+1 l12: dec rcx jnz l11 mov rbx,0 call original_ascii jmp _start add_rol: display msg1,msg1len accept num,5 call ascii_original mov [num1],bx display msg2,msg2len accept num,5 call ascii_original mov [num2],bx mov rax,0 mov rbx,0 mov rcx,0 mov cx,16 mov ax,[num1] mov bx,[num2] l15: ;add rax,rax shl ax,1 jnc l66 add ax,bx l66: dec cl jnz l15 ;mov bx,ax call original_ascii exit: mov rax,60 mov rbx,0 syscall ascii_original: mov esi,num mov ecx,4 mov bx,0 l2: rol bx,4 mov al,[esi] cmp al,39h jbe l3 sub al,07h l3: sub al,30h mov ah,0 add bx,ax inc esi loop l2 ret original_ascii: mov ecx,4 mov esi,number l4: rol ax,4 mov dl,al and dl,0fh cmp dl,09h jbe l5 add dl,07h l5: add dl,30h mov [esi],dl inc esi loop l4 display number,4 ret