;----------------------------------------------------------------
; LD231.ASM
; Detecting a keypress on a 4x4 keypad. 
; ASM Code for the DECE Microprocessor.
; C.P. Diduch, 2001.
;----------------------------------------------------------------
.EQU	OPORT	0x0002		; #define OPORT 0x0002
.EQU    IPORT   0x0001          ; #define IPORT 0x0000
        .ORG    0x8000          ;
				; void main() {
                                ; do {
K0:     ADDL    R0, NULL, 0     ;    outport(OPORT, 0x0000);
	STOREP	OPORT, R0	;
K1:     LOADP   R0, IPORT       ;    do {col = 0x00F0 
	ANDL	R0, R0, 0x00F0	;               & inport(IPORT);} 
	SUBL	NULL, R0, 0x0F0 ;    while (col == 0x0F0);
        JMPZ    K1              ;
                                ;
        STOREP  0x0003, R0      ; outport(0x0003, col);
        JMP     K0              ; }
;----------------------------------------------------------------