incrementExample (2).asm

;Assembly code to show how to increment a variable and print the value

section	.data
incMessage db "The inc value is :"
incMessageLen equ $-incMessage
cr db 10; newline
incValue db 5 ; the variable to be incremented

section .bss

section	.text
   global _start         ;must be declared for using gcc
_start:                  ;tell linker entry point
  inc byte [incValue] ; increment the value in the variable
  mov eax, [incValue] ;  move the incValue variable in eax
  add eax, 48 ; convert the integer into ascii value to print
  mov [incValue], eax ; Put the value back variable

; write the incremented statement to screen.  
  mov eax, 4 ; System call the screen
  mov ebx, 1 ; standard out
  mov ecx,  incMessage; print inc message
  mov edx, incMessageLen; Length of message
  int  80h ; interrupt

; write the incremented value to screen.  
  mov eax, 4 ; System call the screen
  mov ebx, 1 ; standard out
  mov ecx,  incValue; print value 
  mov edx, 1; One byte is size
  int  80h ; interrupt

; write the incremented value to screen.  
  mov eax, 4 ; System call the screen
  mov ebx, 1 ; standard out
  mov ecx,  cr; newline
  mov edx, 1; One byte is size
  int  80h ; interrupt
  
; write the news line to screen.  Same as endl in C++ 
   ;exit program
   mov	eax,1 ;system call exit
   int	0x80  ;call interrupt