/*
 * LAB 7
 * factorial and fibonacci, with LCDINT
 * updated 11/29/01 (talby) */

#include <v2_17g2.asm>

	.sect .data
// START DO NOT MODIFY ****************************
numprompt:
	.asciz	"ENTER when ready"
factprompt:
	.asciz	"Fact("
fibprompt:
	.asciz	"Fib("
spaces:	.asciz	"                "

	.sect .text
main:	ldx	#spaces		// a bunch of initializations
	ldaa	#1
	jsr	LCDLINE
	ldx	#spaces
	ldaa	#2
	jsr	LCDLINE
mainloop:
	jsr	getnum		// returns B
	jsr	clearend
	jsr	putfact		// expects B
	jsr	clearend
// UNCOMMENT (and implement) FOLLOWING CODE FOR A X+
//	jsr	getnum
//	jsr	clearend
//	jsr	putfib
//	jsr	clearend
	bra	mainloop

getnum:
//Expects: nothing
//Returns: SWITCHES in ACCB
//Notes: prompts, waits for a keypress. clobbers A,X
	ldx	#numprompt
	ldaa	#1
	jsr	LCDLINE		// display a null-terminated string
	jsr	GETCHAR		// faking an interrupt
	clra
	ldab	SWITCHES
	rts

putfact:
//Expects: user input in ACCB
//Returns: nothing
//Notes: prints ACCB (user input), then calculates & prints fact(B)
	ldx	#factprompt
	ldaa	#2
	jsr	LCDLINE
	clra
	jsr	LCDINT		// expects :-D
	ldaa	#')'
	jsr	LCD_CHAR
	ldaa	#'='
	jsr	LCD_CHAR
	tba
	jsr	factorial	// expects: B
	jsr	LCDINT		// expects: D
	rts

putfib:
//Expects: user input in ACCB
//Returns: nothing
//Notes: prints ACCB (user input), then calculates & prints fib(B)
	ldx	#fibprompt
	ldaa	#2
	jsr	LCDLINE
	clra
	jsr	LCDINT
	ldaa	#')'
	jsr	LCD_CHAR
	ldaa	#'='
	jsr	LCD_CHAR
	tba
	jsr	fibonacci
	jsr	LCDINT
	rts

clearend:
//Expects: nothing
//Returns: nothing
//Notes: prints spaces to clear the end of a previously written line
	ldaa	#' '
	jsr	LCD_CHAR
	jsr	LCD_CHAR
	jsr	LCD_CHAR
	jsr	LCD_CHAR
	rts

// END DO NOT MODIFY ****************************

factorial:
//Expects: unsigned integer in ACCA
//Returns: fact(A) in ACCD
//Notes: If ACCA contains a negative number, return 0.
	rts

fibonacci: 		// For X+
//Expects: unsigned integer in ACCA
//Returns: fib(A) in ACCD
//Notes: If ACCA contains a negative number, return 0.
	rts