;  Executable name : EATSYSCALL
; Version : 1.0
; created date: 1/7/2009
; last update: 1/7/2009
; Description : A simple assembly app for Linux, using NASM 2.05,
;              demonstrating the use of Linux INT 80H syscalls
;           to display text.
;
;  Build using these commands:
;   nasm -f elf -g -F stabs eatsyscall.asm
;   ld -o eatsyscall eatsyscall.o
;

SECTION .data   ; Section containing intialized data

EatMsg: db "Eat at Joe's!", 10
EatLen: equ $-EatMsg

SECTION .bss     ; Section containing uninitialized data
SECTION .text     ; Section containing code

global _start         ; Linker needs this to find the entry point!

_start:
        nop                  ; This no-op keeps gdb happy (see text)
        mov eax, 4       ; Specify sys_write syscall
        mov ebx, 1       ; specify file descriptor 1: Standard Output
        mov ecx, EatMsg   ; pass offset of the message
        mov edx, EatLen    ; pass the length of the message
        int 80H                    ; make syscall to output the text to stdout

        mov eax, 1             ; Specify exit syscall
        mov ebx, 0             ; return a code of zero
        int 80H                    ; make syscall to terminate the program