N		equ	30	; array count
notfound	equ	-1
key		equ	190	; define the searching key
		
		org	$1000
result		rmw	1	; reserve a word for result

		org	$1500	; starting address of the program
		ldy	#N	; set up loop count
		ldd	#notfound
		std	result	; initialize the search result
		ldd	#key
		ldx	#vec_x	; place the starting address of vec_x in X
loop		cpd	2,X+	; compare the key with array element
		beq	found
		dbne	Y,loop	; decrement the count and check if done
		bra	done
found		dex
		dex
		stx	result
done		swi

vec_x		dw	13,15,320,980,42,86,130,319,430,4 
		dw	90,20,18,55,30,51,37,89,550,39
		dw	78,1023,897,930,880,810,650,710,300,190
		end