Exercise 7.3_1   and 7.3_2  PAG  196


1.	mov	ax,	1234h
	xchg	ah,	al   ;		ax = 3412h

	mov	ax,	1234h
	mov	bx,	5678h
	xchg	ax,	bx   ;		ax = 5678h
;					bx = 1234h

	mov	ax,	1234h
	mov	bx,	5678h	
	xchg	ah,	bl  ;		ax = 7834h
;					bx = 5612h
	mov	ax,	1111h
	mov	bx,	2222h	
	mov	cx,	3333h
	xchg	ax,	bx
	xchg	ax,	cx  ;		ax = 3333h
					bx = 1111h
					cx = 2222h


2.  	mov	ax, 	0  ;
	mov	bx,	10
	mov	dx, 	9

	xchg	bx,	ax

	push	ax ;
	push	bx  ;
	push	dx  ;

	xchg	dx,	bx

	pop	dx
	pop	bx
	pop	ax