CSC231 Mini Lab 1 Solution and Discussion

--D. Thiebaut 09:38, 12 September 2012 (EDT)

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Solution 1

;;; minilab1.asm
;;; D. Thiebaut
;;; prints this string on the screen:
;;;
;;; 	*********************************
;;;     * Welcome to CSC231             *
;;;     * Home of the Assembly Language *
;;;     *********************************


	section	.data

msg	db	"*********************************", 10
	db	"* Welcome to CSC231             *", 10
	db	"* Home of the Assembly Language *", 10	
	db	"*********************************", 10, 10
	
msgLen	equ	$-msg

	section	.text
	global	_start
_start:
	mov	eax,4
	mov	ebx,1
	mov	ecx,msg
	mov	edx,msgLen
	int	0x80

;;; exit
	mov	eax,1
	mov	ebx,0
	int	0x80

Solution 2

;;; minilab1_v1.asm
;;; D. Thiebaut
;;; prints this string on the screen:
;;;
;;; 	*********************************
;;;     * Welcome to CSC231             *
;;;     * Home of the Assembly Language *
;;;     *********************************


	section	.data

msg	db	"*********************************", 10
msgLen1	equ	$-msg	
	db	"* Welcome to CSC231             *", 10
	db	"* Home of the Assembly Language *", 10	
msgLen2	equ	$-msg
	
	section	.text
	global	_start
_start:
	
;;; print first 3 lines
	mov	eax,4
	mov	ebx,1
	mov	ecx,msg
	mov	edx,msgLen2
	int	0x80

;;; print first line back, to close box
	mov	eax,4
	mov	ebx,1
	mov	ecx,msg
	mov	edx,msgLen1
	int	0x80

;;; exit
	mov	eax,1
	mov	ebx,0
	int	0x80

What is the trade-off?

• Generate the listing of the assembly:

      nasm -f elf -F stabs minilab1_v1