; Author: 	Example
; Date:		March 31, 2011
;
; Description:
; The program is a simple guessing game for a number between 0 and 9.
; The user gets 10 tries to guess the number, if their guess is high
; display to high, if their guess is low display to low, and if they don't
; right in 10 tries, display fail.
; If they guess correct display the number of attempts
;
; Variables:
;	R0: display number of tries (ascii)
;	R1: 
;	R2: guess counter
;	R3: compares guess to value
;	R4: 
;	R5: ascii mask (x30)
;	R6: ascii target value (negative)
;	R7:
;
; Initialization
;
	.ORIG x3000

	LD R6, val      ;r6 will hold the # to guess
	LD R5, ascii    ;get the ascii mask
	ADD R6, R6, r5  ;ascii mask to display guess target value
	AND R2, R2, #0	;clear r2, counter	
	NOT R6, R6      ;prep R6 for comparsion (-R6) 
	ADD R6, R6, #1  ;2's complement of R6

;;;;;;;;
; Main loop for guessing game
;;;;;;;;
loop    LEA R0, guess   		; load guess string
		PUTS			; display "?" to console (string must be in R0)
		GETC			; get guess value (ascii), does not echo to display, guess value in R0
		OUT			; echo guess value, R0 
		ADD r2, r2, #1		; increment counter
		ADD r1, r2, #-10 	; compare attempts, max 10.
		BRz fail         	; max attempts reached (10), print results (fail) and halt
		ADD R3, R6, R0  	; compare guess to value (guess - value)
		BRn low			; negative, guess too small, branch low
		BRp high		; positive, guess too big, branch high
					; zero, guess correct, fall thru, and print results
		LEA R0, tries		; load the tries string
		PUTS		
		ADD R0, R2, R5 		; prep number of tries (R2) for display by adding ascii mask (R5)		
		OUT			; display number of tries
		HALT			; halt program
;;;;;;;;
; Display feedback
;;;;;;;;

;;;;;;;;
; Failure to guess
;;;;;;;;
fail		LEA R0, noob	;load noob string
			puts
			HALT	;exit
;;;;;;;;
; Guess too high
;;;;;;;;
high    	LEA R0, big		; load too big string
			PUTS		
			BRnzp loop		;get back in the loop

;;;;;;;;;
; Guess to low
;;;;;;;;;
low    		LEA R0, small	; load too small strng
			PUTS		
			BRnzp loop		;get back in the loop

;;;;;;
; Variables
;;;;;;

val		.FILL	#6
ascii		.FILL	1	x0030
guess	.STRINGZ	"? "
small	.STRINGZ	"\nHigher\n"
big		.STRINGZ	"\nLower\n"
tries		.STRINGZ	"\nTries: "
noob	.STRINGZ	"\nFail"			

		.END