**********
* Program NUM_ODD (6811)
*
* Searches memory locations $E000 - $E0FF and outputs the number
* of bytes which have an odd value.
*
* Illustrates use of indexed addressing and use of CPX.
*
* P. H. Anderson, MSU, 20 Sept 90; 15 Jan 93
**********

PSCT	EQU  $C000
DSCT	EQU  $D000
IDSCT	EQU  $D300

REG_BASE	EQU  $1000
STACKTP		EQU  $0045

PORTB	EQU  $04
PORTC	EQU  $03
DDRC	EQU  $07

	ORG PSCT
	
	LDS #STACKTP

	LDY #REG_BASE

	CLR DDRC,Y	* port c configured as 8-bit input
*			* although switches not used in this program
	CLR NUM_ODD	* initialize

	LDX #$E000	* index reg points to first location
L1
	LDAA 00,X	* get the value
	LSRA		* shift right, lsb in CY
	BCC AROUND	* value is even
	INC NUM_ODD	* otherwise it was odd
AROUND
	INX		* pointer incremented
	CPX #$E100	* gone to far?
	BNE L1		* if not continue

	LDAA NUM_ODD	* if done, display number of odd
	STAA PORTB,Y

	SWI		* return control to monitor

	ORG DSCT

NUM_ODD RMB 1