%macro scall 4
    mov rax, %1      
    mov rdi, %2      
    mov rsi, %3      
    mov rdx, %4      
    syscall          
%endmacro

section .data
    m1 db 10, "Enter 4 digit hex no."
    l1 equ $-m1      

    m2 db 10, 13, "Equivalent BCD no. is: "
    l2 equ $-m2      

section .bss
    buf resb 6        
    digitcount resb 1 
    char_ans resb 4   

section .text
global _start
_start:
    scall 01, 01, m1, l1      
    scall 0, 0, buf, 5        
    call accept_proc          
    mov ax, bx                
    call h2bproc    

;---------------exit--------------------------
    mov rax, 60               
    mov rdi, 0                
    syscall                   

;----------------HEX to BCD-------------------
h2bproc:
    mov rbx, 0Ah              ; Set divisor to 10 (hex to decimal conversion)

back:
    xor rdx, rdx              ; Clear rdx for division
    div rbx                   ; Divide by 10
    push dx                   ; Push the remainder on the stack
    inc byte [digitcount]    ; Increment digit count
    cmp rax, 0h              ; Check if quotient is zero
    jne back                  ; If not, continue
    scall 01, 01, m2, l2      ; Print "Equivalent BCD no. is"

print_bcd:
    pop dx                    ; Pop the remainder from the stack
    add dl, 30h               ; Convert to ASCII character
    mov [char_ans], dl        ; Store the character in char_ans
    scall 01, 01, char_ans, 1 ; Print the character
    dec byte [digitcount]    ; Decrement digit count
    jnz print_bcd             ; If more digits, print next
ret

;-------------------accept procedure-----------------
accept_proc:
    xor bx, bx                
    mov rcx, 4                
    mov rsi, buf              

next_digit:
    shl bx, 04               
    mov al, [rsi]             
    cmp al, 39h               
    jbe label1                
    sub al, 07h               
label1:
    sub al, 30h               
    add bx, ax                
    inc rsi                   
    loop next_digit           
    ret