workingexample.asm

; ubuntu@ubuntu:~/Desktop/usr/bin$ ./nasm -f elf hello.asm
; ubuntu@ubuntu:~/Desktop/usr/bin$ gcc -o hello hello.o
; ubuntu@ubuntu:~/Desktop/usr/bin$ ./hello
; a=5, eax=7


extern printf
        SECTION .data		; Data section, initialized variables

	a:	dd	5		; int a=5;
fmt:    db "a=%d, eax=%d", 10, 0 ; The printf format, "\n",'0'


        SECTION .text                   ; Code section.

        global main ; the standard gcc entry point
main:				; the program label for the entry point
        push    ebp		; set up stack frame
        mov     ebp,esp

	mov	eax, [a]	; put a from store into register
	add	eax, 2		; a+2
	push	eax		; value of a+2
        push    dword [a]	; value of variable a
        push    dword fmt	; address of ctrl string
        call    printf		; Call C function
        add     esp, 12		; pop stack 3 push times 4 bytes

        mov     esp, ebp	; takedown stack frame
        pop     ebp		; same as "leave" op

	mov	eax,0		;  normal, no error, return value
	ret			; return