Write X86/64 ALP to convert 4-digit Hex number into its equivalent BCD number and 5-digit BCD number into its equivalent HEX number. Make your program user friendly to accept the choice from user for: (a) HEX to BCD b) BCD to HEX (c) EXIT. Display proper strings to prompt the user while accepting the input and displaying the result.(wherever necessary, use 64-bit registers)

                                            Savitribai Phule Pune University
                            Second Year of Computer Engineering (2015 Course)
                                                     210257: Microprocessor Lab
                                                                Assignment No.03

Problem Statement: Write X86/64 ALP to convert 4-digit Hex number into its equivalent BCD number and 5-digit BCD number into its equivalent HEX number. Make your program user friendly to accept the choice from user for:
(a) HEX to BCD b) BCD to HEX (c) EXIT.
Display proper strings to prompt the user while accepting the input and displaying the result.(wherever necessary, use 64-bit registers) 
;************************************************************
section .data
    menumsg db 10,10,'###### Menu for Code Conversion ######'
        db 10,'1: Hex to BCD'
        db 10,'2: BCD to Hex'
        db 10,'3: Exit'
        db 10,10,'Please Enter Choice::'
    menumsg_len equ $-menumsg
  

    hexinmsg db 10,10,'Please enter 4 digit hex number::'
    hexinmsg_len equ $-hexinmsg

    bcdopmsg db 10,10,'BCD Equivalent::'
    bcdopmsg_len equ $-bcdopmsg

    bcdinmsg db 10,10,'Please enter 5 digit BCD number::'
    bcdinmsg_len equ $-bcdinmsg

    hexopmsg db 10,10,'Hex Equivalent::'
    hexopmsg_len equ $-hexopmsg

;************************************************************

section .bss

    numascii resb 06  ;common buffer for choice, hex and bcd input
    outputbuff resb 02
    dispbuff resb 08

    %macro display 2
       mov rax,01
       mov rdi,01
       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 .text

    global _start
_start:

menu:    display menumsg,menumsg_len
    accept numascii,2

    cmp byte [numascii],'1'
    je hex2bcd_proc



    cmp byte [numascii],'2'
    je bcd2hex_proc
  

    cmp byte [numascii],'3'
    je exit
    jmp _start

exit:
    mov rax,60
    mov rbx,0
    syscall
;************************************************************
hex2bcd_proc:
    display hexinmsg,hexinmsg_len
    accept numascii,5
    call packnum
    mov ax,bx  
    mov rcx,0
    mov bx,10        ;Base of Decimal No. system
h2bup1:    mov dx,0
    div bx
    push rdx
    inc rcx
    cmp ax,0
    jne h2bup1
    mov rdi,outputbuff

h2bup2:    pop rdx
    add dl,30h
    mov [rdi],dl
    inc rdi
    loop h2bup2
  
    display bcdopmsg,bcdopmsg_len
    display outputbuff,5
    jmp menu
;************************************************************
bcd2hex_proc:
    display bcdinmsg,bcdinmsg_len
    accept numascii,6

    display hexopmsg,hexopmsg_len

    mov rsi,numascii
    mov rcx,05
    mov rax,0
    mov ebx,0ah

b2hup1:    mov rdx,0
    mul ebx
    mov dl,[rsi]
    sub dl,30h
    add rax,rdx
    inc rsi
    loop b2hup1
    mov ebx,eax
    call disp32_num
    jmp menu
;************************************************************
packnum:
    mov bx,0
    mov ecx,04
    mov esi,numascii
up1:
    rol bx,04
    mov al,[esi]
    cmp al,39h
    jbe skip1
    sub al,07h
skip1:    sub al,30h
    add bl,al
    inc esi
    loop up1
    ret

;************************************************************
disp32_num:
    mov rdi,dispbuff    ;point esi to buffer
    mov rcx,08        ;load number of digits to display

dispup1:
    rol ebx,4        ;rotate number left by four bits
    mov dl,bl        ;move lower byte in dl
    and dl,0fh        ;mask upper digit of byte in dl
    add dl,30h        ;add 30h to calculate ASCII code
    cmp dl,39h        ;compare with 39h
    jbe dispskip1        ;if less than 39h akip adding 07 more
    add dl,07h        ;else add 07

dispskip1:
    mov [rdi],dl        ;store ASCII code in buffer
    inc rdi            ;point to next byte
    loop dispup1        ;decrement the count of digits to display
                ;if not zero jump to repeat

    display dispbuff+3,5    ;Dispays only lower 5 digits as upper three are '0'
  
    ret
;******************OUTPUT****************************************

;###### Menu for Code Conversion ######
;1: Hex to BCD
;2: BCD to Hex
;3: Exit

;Please Enter Choice::1


;Please enter 4 digit hex number::000F


;BCD Equivalent::15

;###### Menu for Code Conversion ######
;1: Hex to BCD
;2: BCD to Hex
;3: Exit

;Please Enter Choice::2


;Please enter 5 digit BCD number::00015


;Hex Equivalent::0000F