;-----------------------------------------------------------------
; EX68.ASM  IMPLEMENTING COMBINATORIAL LOGIC	C.P. Diduch 2001
;
; Implement the Boolean equation, a0 = b5'b2b1'b0 or b7b6'b5'b2.
; Assume output port data at OPORT = a15 ... a0.
; Assume input port data at IPORT = b15 ... b0.
;
;    Author(s):
; Signature(s):                              Date:
;-----------------------------------------------------------------
.EQU	IPORT	0		; #define IPORT 0
.EQU	OPORT	2		; #define OPORT 2
				;
        .ORG    0x8000          ; "assign the following to ROM"
				;
                                ; void main(void) {
				;
                                ; do {
B0:     LOADP   R0, IPORT       ;    R0 = inport(IPORT);
        ADD     R1, R0, NULL    ;    R1 = R0; 
        ANDL    R1, R1, 0x027   ;    if(((R0 & 0x0027)==0x0005)  
        SUBL    NULL, R1, 0x005 ;     
        JMPZ    B1              ;
				;
	ADD	R1, R0, NULL	;     | ((R0 & 0x00E4)==0x0084)){	 
	ANDL	R1, R1, 0x0E4	; 
	SUBL	NULL, R1, 0x084	;    
        JMPNZ   B2              ;   
				;    
B1:     ADDL    R0, NULL, 1     ;      outportb(OPORT, 1);
        STOREP  OPORT, R0       ;    
        JMP     B3              ;       }
				;
B2:     ADDL    R0, NULL, 0     ;    else { 
        STOREP  OPORT, R0       ;       outportb(OPORT, 0);
                                ;       }
B3:     JMP     B0              ;    }
                                ; }