***Listing 1 for di2362: Frequency Multiplier code***

.include "1200def.inc"
.device AT90S1200

.def		cnt		=r16			;
.def		temp_1	=r17			;
.def		temp_2	=r18			;
.def		temp_3	=r19			;
.def		temp_4	=r20			;
.def		temp_5	=r21			;
.def		temp_6	=r22			;
.def		number	=r23			;
.def		pulse		=r24			;
.def		delay_1	=r25			;
.def		delay_2	=r26			;
.def		cnt_1		=r27			;
.def		cnt_2		=r28			;
							;
reset:						;
		rjmp	init				;
int:							;
		in	temp_4,		PINB	;	read input
		andi	temp_4,		$07	;
		mov	temp_5,		temp_4;
		mov	temp_6,		temp_4;
		lsl	temp_5			;
		lsr	temp_6			;
		ldi	temp_2,		$0	;
		cp	number,		temp_4;
		brne	next_1			;
		ldi	temp_2,		$1	;
next_1:						;
		dec	temp_2			;
		breq	next_2			;
		out	PORTD,		pulse	;
		inc	pulse				;
next_2:						;
		cp	number,		temp_4;
		brlo	dec_cnt			;
		cp	number,		temp_5;
		brlo	inc_cnt			;
		sec					;
		rol	cnt_1				;
		rol	cnt_2				;
		brcc	int_out			;
cnt_overflow:					;
		ldi	cnt_1,		$ff	;
		ldi	cnt_2,		$ff	;
		rjmp	int_out			;
inc_cnt:						;
		add	cnt_2,		temp_3;
		breq	inc_1				;
		add	cnt_1,		cnt_2	;
		brcc	inc_1				;
		inc	cnt_2				;
		breq	cnt_overflow		;
inc_1:						;
		inc	cnt_1				;
		brne	int_out			;
		inc	cnt_2				;
		breq	cnt_overflow		;
		rjmp	int_out			;
dec_cnt:						;
		cp	number,		temp_6;
		brlo	half_cnt			;
		add	cnt_2,		temp_3;
		breq	dec_1				;
		sub	cnt_1,		cnt_2	;
		brcc	dec_1				;
		subi	cnt_2,		$1	;
		brcs	cnt_underflow		;
dec_1:						;
		subi	cnt_1,		$1	;
		brcc	int_out			;
		subi	cnt_2,		$1	;
		brcc	int_out			;
cnt_underflow:					;
		ldi	cnt_1,		$1	;
		ldi	cnt_2,		$0	;
int_out:						;
		ldi	number, 	$0		;
		rjmp	loop_1			;
half_cnt:						;
		clc					;
		ror	cnt_2				;
		ror	cnt_1				;
		rjmp	int_out			;
init:							;
		ser	temp_1			;
		out	PORTB,		temp_1;
		out	PORTD,		temp_1;
		ldi	temp_1,		$0	;
		out	DDRB,			temp_1;
		ldi	temp_1,		$1	;
		out	DDRD,			temp_1;
		ldi	delay_1,	$ff		;
		ldi	delay_2,	$ff		;
		ldi	temp_1,		$40	;
		out	GIMSK,		temp_1;
		ldi	temp_1,		$3	;
		out	MCUCR,		temp_1;
		ldi	pulse,		$0	;
		ldi	number,		$0	;
		ldi	temp_3,		$0	;
		in	temp_4,		PINB	;
		andi	temp_4,		$07	;
		mov	temp_5,		temp_4;
		mov	temp_6,		temp_4;
		lsl	temp_5			;
		lsr	temp_6			;
							;
loop_1:						; endless loop
		sei					;
		mov	delay_1,	cnt_1		;
		mov	delay_2,	cnt_2		;
loop_2:						; delay loop
		subi	delay_1,	$1		;
		brcc	loop_2			;
		subi	delay_2,	$1		;
		brcc	loop_2			;
		cli					;
		out	PORTD,		pulse	; send output
		inc	pulse				;
		sbrs	pulse,		$0	;
		inc	number			;
		rjmp	loop_1			;