a program in assembly language to to move immediate data to Registers.

SYS_EXIT  equ 1

SYS_READ  equ 3

SYS_WRITE equ 4

STDIN     equ 0

STDOUT    equ 1

segment .data

   msg1 db "Enter a digit ", 0xA,0xD

   len1 equ $- msg1

   msg2 db "Please enter a second digit", 0xA,0xD

   len2 equ $- msg2

   msg3 db "The sum is: "

   len3 equ $- msg3

segment .bss

   num1 resb 2

   num2 resb 2

   res resb 1   

section  .text

   global _start    ;must be declared for using gcc

        

_start:             ;tell linker entry point

   mov eax, SYS_WRITE        

   mov ebx, STDOUT        

   mov ecx, msg1        

   mov edx, len1

   int 0x80               

   mov eax, SYS_READ

   mov ebx, STDIN 

   mov ecx, num1

   mov edx, 2

   int 0x80           

   mov eax, SYS_WRITE       

   mov ebx, STDOUT        

   mov ecx, msg2         

   mov edx, len2        

   int 0x80

   mov eax, SYS_READ 

   mov ebx, STDIN 

   mov ecx, num2

   mov edx, 2

   int 0x80       

   mov eax, SYS_WRITE        

   mov ebx, STDOUT        

   mov ecx, msg3         

   mov edx, len3        

   int 0x80

   ; moving the first number to eax register and second number to ebx

   ; and subtracting ascii '0' to convert it into a decimal number

        

   mov eax, [num1]

   sub eax, '0'

        

   mov ebx, [num2]

   sub ebx, '0'

   ; add eax and ebx

   add eax, ebx

   ; add '0' to to convert the sum from decimal to ASCII

   add eax, '0'

   ; storing the sum in memory location res

   mov [res], eax

   ; print the sum

   mov eax, SYS_WRITE       

   mov ebx, STDOUT

   mov ecx, res        

   mov edx, 1       

   int 0x80

exit:   

  

   mov eax, SYS_EXIT  

   xor ebx, ebx

   int 0x80

When the above code is compiled and executed, it produces the following result −

Enter a digit:

3

Please enter a second digit:

4

The sum is:

7

The program with hardcoded variables −

 Live Demo

section  .text

   global _start    ;must be declared for using gcc

        

_start:             ;tell linker entry point

   mov   eax,'3'

   sub     eax, '0'

        

   mov   ebx, '4'

   sub     ebx, '0'

   add   eax, ebx

   add   eax, '0'

        

   mov   [sum], eax

   mov   ecx,msg 

   mov   edx, len

   mov   ebx,1    ;file descriptor (stdout)

   mov   eax,4    ;system call number (sys_write)

   int   0x80     ;call kernel

        

   mov   ecx,sum

   mov   edx, 1

   mov   ebx,1    ;file descriptor (stdout)

   mov   eax,4    ;system call number (sys_write)

   int   0x80     ;call kernel

        

   mov   eax,1    ;system call number (sys_exit)

   int   0x80     ;call kernel

        

section .data

   msg db "The sum is:", 0xA,0xD

   len equ $ - msg  

   segment .bss

   sum resb 1