1 files changed, 116 insertions(+), 12 deletions(-)

M src/cart.asm

@@ 13,7 13,7 @@
 
 PPUCTRL             .equ $2000 
 PPUMASK             .equ $2001 
-PPUSTATUS           .equ $2002 ; Using BIT PPUSTATUS preserves the previous contents of A.
+PPUSTATUS           .equ $2002 
 SPRADDR             .equ $2003 
 PPUSCROLL           .equ $2005 
 PPUADDR             .equ $2006 


@@ 51,8 51,6 @@ BUTTON_A            .equ #$80
 ;; variables
 
 	.enum $0000
-rate                    .dsb 1 
-timer                   .dsb 1 
 position                .dsb 1 
 cursor                  .dsb 1 
 note                    .dsb 1 


@@ 61,6 59,9 @@ selection               .dsb 1
 down@input              .dsb 1 
 last@input              .dsb 1 
 next@input              .dsb 1 
+rate                    .dsb 1 
+timer                   .dsb 1 
+seed                    .dsb 1 
 	.ende 
 
 ;; reset


@@ 289,9 290,6 @@ RedrawOctave:
 	JSR DrawAt
 	RTS 
 
-RedrawLine:
-	RTS 
-
 RedrawTimeline:
 	LDX #$00
 @loop:                         ;


@@ 330,6 328,110 @@ DrawAt:                        ; (a:id,x,y)
 	STA PPUDATA
 	RTS 
 
+DoIncNote:
+	INC note
+	LDA note
+	CMP #$0c
+	BNE @done
+	LDA #$00
+	STA note
+@done:
+	JMP DoOperationEnd
+
+DoDecNote:
+	DEC note
+	LDA note
+	CMP #$ff
+	BNE @done
+	LDA #$0b
+	STA note
+@done:
+	JMP DoOperationEnd
+
+DoIncOctave:
+	INC octave
+	LDA octave
+	CMP #$08
+	BCC @done
+	LDA #$00
+	STA octave
+@done:
+	JMP DoOperationEnd
+
+DoDecOctave:
+	DEC octave
+	LDA octave
+	CMP #$ff
+	BNE @done
+	LDA #$08
+	STA octave
+@done:
+	JMP DoOperationEnd
+
+DoRandomNote:
+	LDA seed
+@loop:
+	SEC 
+	SBC #$0c
+	CMP #$0c
+	BCS @loop
+	STA note
+	INC seed
+	JMP DoOperationEnd
+
+DoIncMetro:
+	INC rate
+	LDA rate
+	CMP #$08
+	BCC @done
+	LDA #$01
+	STA rate
+@done:
+	JMP DoOperationEnd
+
+DoDecMetro:
+	DEC rate
+	LDA rate
+	CMP #$00
+	BNE @done
+	LDA #$08
+	STA rate
+@done:
+	JMP DoOperationEnd
+
+DoRandomPosition:
+	LDA seed
+@loop:
+	SEC 
+	SBC #$10
+	CMP #$10
+	BCS @loop
+	STA position
+	JMP DoOperationEnd
+
+DoOperation:
+	LDX position
+	LDA $10,x
+	CMP #$00                     ;
+	BEQ DoIncNote
+	CMP #$01
+	BEQ DoDecNote
+	CMP #$02
+	BEQ DoIncOctave
+	CMP #$03
+	BEQ DoDecOctave
+	CMP #$04
+	BEQ DoRandomNote
+	CMP #$05
+	BEQ DoIncMetro
+	CMP #$06
+	BEQ DoDecMetro
+	CMP #$07
+	BEQ DoRandomPosition
+
+DoOperationEnd:
+	RTS 
+
 ;; nmi phase
 
 NMI:                           ;


@@ 361,13 463,15 @@ SaveJoy:                       ; [skip]
 	STA $4014                    ; set the high byte (02) of the RAM address, start the transfer
 
 RunTimer:
+	INC seed
 	INC timer
 	; check if timer has reached rate
 	LDA timer
 	CMP rate
-	BNE @done
+	BNE @done                    ; skip if timer is less than rate
 	LDA #$00
-	STA timer
+	STA timer                    ; reset timer
+	JSR DoOperation
 	INC position
 	; check if position has reached 16
 	LDA position


@@ 377,9 481,7 @@ RunTimer:
 	STA position
 @done:
 
-RunOperator:
-@done:
-	; cleanup
+Cleanup:
 	JSR Redraw
 	LDA PPUSTATUS
 	LDA #$00                     ; No background scrolling


@@ 400,7 502,9 @@ TimelinePositions:
 
 Sequence:
 	; .db $00,$01,$05,$01,$02,$06,$03,$04,$00,$01,$05,$01,$02,$06,$03,$07
-	.db $00,$01,$02,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
+	; .db $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
+	; .db $01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01,$01
+	.db $04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04,$04
 
 ;; Vectors