Reintegrate wbw -> trunk

Source/util.asm

@@ -459,6 +459,53 @@ MULT8_LOOP:
 MULT8_NOADD:
 	DJNZ MULT8_LOOP
 	RET
+	
+	
+;
+; SET A BIT IN BYTE ARRAY AT HL, INDEX IN A
+;
+BITSET:
+	CALL	BITLOC		; LOCATE THE BIT
+	OR	(HL)		; SET THE SPECIFIED BIT
+	LD	(HL),A		; SAVE IT
+	RET			; RETURN
+;
+; CLEAR A BIT IN BYTE ARRAY AT HL, INDEX IN A
+;
+BITCLR:
+	CALL	BITLOC		; LOCATE THE BIT
+	CPL			; INVERT ALL BITS
+	AND	(HL)		; CLEAR SPECIFIED BIT
+	LD	(HL),A		; SAVE IT
+	RET			; RETURN
+;
+; GET VALUE OF A BIT IN BYTE ARRAY AT HL, INDEX IN A
+;
+BITTST:
+	CALL	BITLOC		; LOCATE THE BIT
+	AND	(HL)		; SET Z FLAG BASED ON BIT
+	RET			; RETURN
+;
+; LOCATE A BIT IN BYTE ARRAY AT HL, INDEX IN A
+; RETURN WITH HL POINTING TO BYTE AND A WITH MASK FOR SPECIFIC BIT
+;
+BITLOC:
+	PUSH	AF		; SAVE BIT INDEX
+	SRL	A		; DIVIDE BY 8 TO GET BYTE INDEX
+	SRL	A		; "
+	SRL	A		; "
+	LD	C,A		; MOVE TO BC
+	LD	B,0		; "
+	ADD	HL,BC		; HL NOW POINTS TO BYTE CONTAINING BIT
+	POP	AF		; RECOVER A (INDEX)
+	AND	$07		; ISOLATE REMAINDER, Z SET IF ZERO
+	LD	B,A		; SETUP SHIFT COUNTER
+	LD	A,1		; SETUP A WITH MASK
+	RET	Z		; DONE IF ZERO
+BITLOC1:
+	SLA	A		; SHIFT
+	DJNZ	BITLOC1		; LOOP AS NEEDED
+	RET			; DONE
 ;
 ; PRINT VALUE OF HL IN DECIMAL WITH LEADING ZERO SUPPRESSION
 ;