tiny_music: auto-generate the frequency table

demos/tiny_music/interrupt_handler.s

@@ -27,8 +27,6 @@ interrupt_handler:
 	tya
 	pha			; save Y
 
-
-
 	inc	$0404		; debug (flashes char onscreen)
 
 
@@ -113,10 +111,6 @@ done_update_song:
 
 done_ay3_irq_handler:
 
-
-
-exit_interrupt:
-
 	pla
 	tay			; restore Y
 	pla
@@ -126,7 +120,7 @@ exit_interrupt:
 	; on II+/IIe (but not IIc) we need to do this?
 interrupt_smc:
 	lda	$45		; restore A
-	plp
+	plp			; restore flags
 
 	rti			; return from interrupt			; 6
 
@@ -134,15 +128,8 @@ interrupt_smc:
 								; typical
 								; ???? cycles
 
-; starts at C4
-frequency_lookup:
-.byte $F4,$E6,$D9,$CD,$C1,$B7,$AC,$A3,$99,$91,$89,$81,$00,$00,$00,$00
-.byte $7A,$73,$6C,$66,$60,$5B,$56,$51,$4C,$48,$44,$40,$00,$00,$00,$00
-.byte $3D,$39,$36,$33,$30,$2D,$2B,$28,$26,$24,$22,$20,$00,$00,$00,$00
-
-; .byte $EE,$E1,$D4,$C8,$BD,$B2,$A8,$9F,$96,$8E,$86,$7E,$00,$00,$00,$00
-; .byte $77,$70,$6A,$64,$5E,$59,$54,$4F,$4B,$47,$43,$3F,$00,$00,$00,$00
-; .byte $3B,$38,$35,$32,$2F,$2C,$2A,$27,$25,$23,$21,$1F,$00,$00,$00,$00
+
+
 
 
 

demos/tiny_music/mockingboard_setup.s

@@ -60,8 +60,6 @@ MOCK_AY_LATCH_ADDR	=	$7	;	1	1	1
 
 mockingboard_init:
 
-
-
 	;=========================
 	; Initialize the 6522s
 	; set the data direction for all pins of PortA/PortB to be output
@@ -166,11 +164,11 @@ init_smc:
 	txa
 	tay
 	lda	(SONG_L),Y
-	jsr	ay3_write_reg
+	jsr	ay3_write_reg		; trashes Y
 	dex
 	bne	init_loop
 
-	; update SONG_L to point to beginning
+	; update SONG_L to point past the init
 	lda	SONG_L
 	clc
 	adc	#14
@@ -179,6 +177,17 @@ init_smc:
 	inc	SONG_H
 no_oflo:
 
+	; create Frequency Table
+	ldx	#12
+make_freq_loop:
+	lda	frequency_lookup,X
+	lsr
+	sta	frequency_lookup+16,X
+	lsr
+	sta	frequency_lookup+32,X
+	dex
+	bpl	make_freq_loop
+
 	rts
 
 
@@ -223,3 +232,12 @@ ay3_write_reg:
 	sty	MOCK_6522_ORB2                                          ; 4
 
 	rts
+
+
+; starts at C4
+frequency_lookup:
+.byte $F4,$E6,$D9,$CD,$C1,$B7,$AC,$A3,$99,$91,$89,$81,$00
+
+;.byte $00,$00,$00,$00
+;.byte $7A,$73,$6C,$66,$60,$5B,$56,$51,$4C,$48,$44,$40,$00,$00,$00,$00
+;.byte $3D,$39,$36,$33,$30,$2D,$2B,$28,$26,$24,$22,$20,$00,$00,$00,$00

demos/tiny_music/music.s

@@ -47,7 +47,10 @@ forever:
 	jmp	forever
 
 
-.include        "mockingboard_setup.s"
+.include "yankee_music.s"
+
 .include        "interrupt_handler.s"
 
-	.include "yankee_music.s"
+; must be last
+.include        "mockingboard_setup.s"
+