CSC231 prog2.asm

--D. Thiebaut 15:03, 4 March 2011 (EST)

---

;;; prog2.asm
;;; D. Thiebaut
;;; a simple demo program to add 2 numbers
;;; together, and store the sum in a 3rd variable
;;; 
;;; Assemble, link and run as follows:
;;;   nasm -f elf asm_io.asm        (do this only once)
;;;   nasm -f elf prog2.asm
;;;   gcc -o prog2 driver.c prog2.o asm_io.o
;;;   ./prog2
;;; 
%include "asm_io.inc"
        
%assign SYS_EXIT        1

        ;; -------------------------
        ;; data segment
        ;; -------------------------
        section .data
a       dd      3
b       dd      5
result  dd      0

        ;; -------------------------
        ;; code area
        ;; -------------------------
        section .text
        global  asm_main
asm_main:       
        mov     eax,[a]
        add     eax,[b]
        mov     [result],eax
        
        mov     eax,[result]          ; pass result to print_int
        call    print_int             ; and print value

        call    print_nl              ; call the function that prints
                                      ; a new blank line

        ;; return to C program

        ret