Update nascom.asm

Source/HBIOS/nascom.asm

@@ -4417,7 +4417,7 @@ OUTNCR: CALL    OUTC            ; Output character in A
 		
 ; ---------------------------------------------------------------------------------------
 
-;	PLAY	O,N,D		; PLAY OCTAVE 0-8, NOTE N (0-11), DURATION (1-8)
+;	PLAY	O,N,D		; PLAY OCTAVE 0-8, NOTE N (0-11), DURATION (1-8) [1/8 - 8/8 SECONDS]
 
 PLAY:	CALL    GETINT          ; GET OCTAVE
 	PUSH	AF		; AND SAVE
@@ -4453,7 +4453,7 @@ PLAY:	CALL    GETINT          ; GET OCTAVE
 	INC	HL		; IN DE
 	LD	E,A		; WHICH IS THE
 	LD	A,(HL)		; FREQUENCY FOR
-	INC	HL		; THE EIGTH
+	INC	HL		; THE EIGHTH
 	LD	D,A		; OCTAVE
 
 	PUSH	DE
@@ -4469,7 +4469,7 @@ PLAY:	CALL    GETINT          ; GET OCTAVE
 	POP	DE
 
 	LD	A,8		; DIVIDE THE
-	SUB	B		; FREQENCY BASED
+	SUB	B		; FREQUENCY BASED
 	JR	Z,SPK_OCTOK	; ON THE OCTAVE
 	LD	B,A
 SPK_OCTDIV:
@@ -4478,23 +4478,34 @@ SPK_OCTDIV:
 	SLA	L	; C<L<0	; TIME WE DIVIDE
 	RL	H	; C<H<C	; THE FREQUENCY
 	DJNZ	SPK_OCTDIV
+
+	JR	NC,SPK_OCTOK	; SET TO MAXIMUM
+	LD	HL,$FFFF	; IF OVERFLOW
+
 SPK_OCTOK:		
-	POP	BC		; RECALL DURATION
-	LD	C,B
-
-	LD	B,16		; DIVIDE BY DURATION
-	XOR	A
-	ADD	HL,HL
-	RLA
-	CP	C
-	JR	C,$+4
-	INC	L
-	SUB	C
-	DJNZ	$-7
-	ADD	A,A
-	CP	C
-	JR	C,$+3
-	INC	HL
+	POP	BC		; MULTIPLY CHL X B
+	PUSH	DE		; SAVE
+
+	EX	DE,HL
+	LD	C,0
+	LD	H,C
+	LD	L,C
+MULSKP:	ADD	HL,DE
+	JR	NC,MULDLP
+	INC	C
+MULDLP:	DJNZ	MULSKP
+
+	SRL	C		; 0>C>C	; BCHL = BCHL / 2
+	RR	H		; C>H>C ;
+	RR	L		; C>L>C	;
+	SRL	C		; 0>C>C	; BCHL = BCHL / 2
+	RR	H		; C>H>C ;
+	RR	L		; C>L>C	;
+	SRL	C		; 0>C>C	; BCHL = BCHL / 2
+	RR	H		; C>H>C ;
+	RR	L		; C>L>C	;
+
+	POP	DE
 ;
 ;	The following SPK_BEEPER routine is a modification of code from 
 ;	"The Complete SPECTRUM ROM DISSASSEMBLY" by Dr Ian Logan & Dr Frank O’Hara
@@ -4622,9 +4633,15 @@ DIV_CANSUB:
 	DEC	A
 	JR	NZ, DIV_LP		; IX = RESULT
 
+;	LD	DE,$FFFF		; IF OVERFLOW SET TO
+;	LD	A,H
+;	OR	L			; MAXIMUM. OCCURS
+;	CALL	NZ,DISP
+;	JR	NZ,DUROVF		; FOR 10MHZ+
+
 	PUSH	IX			; SAVE RESULT IN TABLE
 	POP	DE
-	LD	(IY+2),E
+DUROVF:	LD	(IY+2),E
 	LD	(IY+3),D
 
 	LD	DE,4			; POINT TO NEXT TABLE 
@@ -4637,18 +4654,24 @@ DIV_CANSUB:
 	DJNZ	TBL_LP			; LOOP COUNTER
 	RET
 
-DISP:	PUSH	BC
+DISP:	
+	PUSH	BC
+	PUSH	DE
+	PUSH	HL
 
-;	PUSH	DE
-;	POP	BC
-;	CALL	PRTHEXWORD
-;
-;	PUSH	DE
-;	POP	BC
-;	CALL	PRTHEXWORD
+	PUSH	DE
+	POP	BC
+	CALL	PRTHEXWORD
 
-	LD	A,'*'
+	PUSH	HL
+	POP	BC
+	CALL	PRTHEXWORD
+
+	LD	A,' '
 	CALL	MONOUT
+
+	POP	HL
+	POP	DE
 	POP	BC
 	RET