~rabbits/spacetime: Basic timers

4 files changed, 229 insertions(+), 73 deletions(-)

M build.sh
M src/cart.asm
M src/sprite.chr
M zeropage.lua

M build.sh => build.sh +2 -2

@@ 33,5 33,5 @@ echo "Assembling new cart."
 tools/asm6 src/cart.asm cart.nes
 
 # Run
-# fceux cart.nes --loadlua zeropage.lua
-fceux cart.nes 
+fceux cart.nes --loadlua zeropage.lua
+# fceux cart.nes

M src/cart.asm => src/cart.asm +226 -70

@@ 9,7 9,59 @@
 	.fillvalue $FF ; Sets all unused space in rom to value $FF
 	.org $C000
 
-;; Reset
+;; constants
+
+PPUCTRL             .equ $2000 
+PPUMASK             .equ $2001 
+PPUSTATUS           .equ $2002 ; Using BIT PPUSTATUS preserves the previous contents of A.
+SPRADDR             .equ $2003 
+PPUSCROLL           .equ $2005 
+PPUADDR             .equ $2006 
+PPUDATA             .equ $2007 
+	; APU
+APUCH1VOL           .equ $4000 ; APU
+APUCH1SWP           .equ $4001 
+APUCH1FRQ           .equ $4002 
+APUCH1LEN           .equ $4003 
+APUCH2VOL           .equ $4004 
+APUCH2SWP           .equ $4005 
+APUCH2FRQ           .equ $4006 
+APUCH2LEN           .equ $4007 
+APUCH3CNT           .equ $4008 
+APUCH3SWP           .equ $4009 
+APUCH3FRQ           .equ $400a 
+APUCH3LEN           .equ $400b 
+APUCH4VOL           .equ $400c 
+APUCH4SWP           .equ $400d 
+APUCH4FRQ           .equ $400e 
+APUCH4LEN           .equ $400f 
+SPRDMA              .equ $4014 
+APUCTRL             .equ $4015 
+JOY1                .equ $4016 
+JOY2                .equ $4017 
+BUTTON_RIGHT        .equ #$01 
+BUTTON_LEFT         .equ #$02 
+BUTTON_DOWN         .equ #$04 
+BUTTON_UP           .equ #$08 
+BUTTON_START        .equ #$10 
+BUTTON_SELECT       .equ #$20 
+BUTTON_B            .equ #$40 
+BUTTON_A            .equ #$80 
+
+;; variables
+
+	.enum $0000
+rate                    .dsb 1 
+timer                   .dsb 1 
+position                .dsb 1 
+cursor                  .dsb 1 
+note                    .dsb 1 
+down@input              .dsb 1 
+last@input              .dsb 1 
+next@input              .dsb 1 
+	.ende 
+
+;; reset
 
 RESET:                         ;
 	SEI                          ; disable IRQs


@@ 19,15 71,15 @@ RESET:                         ;
 	LDX #$FF
 	TXS                          ; Set up stack
 	INX                          ; now X = 0
-	STX $2000                    ; disable NMI
-	STX $2001                    ; disable rendering
+	STX PPUCTRL                  ; disable NMI
+	STX PPUMASK                  ; disable rendering
 	STX $4010                    ; disable DMC IRQs
 
-vblankwait1:                   ; First wait for vblank to make sure PPU is ready
-	BIT $2002
-	BPL vblankwait1
+Vblankwait1:                   ; First wait for vblank to make sure PPU is ready
+	BIT PPUSTATUS
+	BPL Vblankwait1
 
-clrmem:                        ;
+Clrmem:                        ;
 	LDA #$00
 	STA $0000, x
 	STA $0100, x


@@ 39,31 91,120 @@ clrmem:                        ;
 	LDA #$FE
 	STA $0200, x                 ; move all sprites off screen
 	INX 
-	BNE clrmem
+	BNE Clrmem
+
+Vblankwait2:                   ; Second wait for vblank, PPU is ready after this
+	BIT PPUSTATUS
+	BPL Vblankwait2
+
+;; begin setup
+
+SetupPalettes:                 ;
+	LDA PPUSTATUS
+	LDA #$3F
+	STA PPUADDR
+	LDA #$00
+	STA PPUADDR
+	LDX #$00
+@loop:                         ;
+	LDA Palettes, x
+	STA PPUDATA
+	INX 
+	CPX #$20
+	BNE @loop
 
-vblankwait2:                   ; Second wait for vblank, PPU is ready after this
-	BIT $2002
-	BPL vblankwait2
-	JSR LoadPalettes
-	JSR LoadAttributes
+SetupAttributes:               ;
+	LDA PPUSTATUS
+	LDA #$23
+	STA PPUADDR
+	LDA #$C0
+	STA PPUADDR
+	LDX #$00
+@loop:                         ;
+	LDA #$00
+	STA PPUDATA
+	INX 
+	CPX #$40
+	BNE @loop
 	JSR Redraw
 
+SetupVariables:
+	LDA #$10
+	STA rate
+	LDA #$40
+	STA note
+
+SetupPlayer:
+	LDA #$88
+	ADC timer
+	STA $0200                    ; set tile.y pos
+	LDA #$02
+	STA $0201                    ; set tile.id
+	LDA #$00
+	STA $0202                    ; set tile.attribute
+
 EnableSprites:                 ;
 	LDA #%10010000               ; enable NMI, sprites from Pattern Table 0, background from Pattern Table 1
-	STA $2000
+	STA PPUCTRL
 	LDA #%00011110               ; enable sprites, enable background, no clipping on left side
-	STA $2001
+	STA PPUMASK
 	LDA #$00                     ; No background scrolling
-	STA $2006
-	STA $2006
-	STA $2005
-	STA $2005
+	STA PPUADDR
+	STA PPUADDR
+	STA PPUSCROLL
+	STA PPUSCROLL
+
+MAIN:
+	; route inputs
+	LDA next@input
+	CMP BUTTON_LEFT
+	BEQ MoveLeft
+	CMP BUTTON_RIGHT
+	BEQ MoveRight
+	JMP MAIN                     ; jump back to Forever, infinite loop
 
-Forever:                       ;
-	JMP Forever                  ; jump back to Forever, infinite loop
+;; General functions
+
+MoveLeft:
+	DEC cursor
+	LDA cursor
+	CMP #$ff
+	BNE @done                    ; when equal skip
+	; wrap around
+	LDA #$0f
+	STA cursor
+@done:                         ;
+	LDA #$00
+	STA next@input
+	STA RedrawTimeline
+	JMP MAIN
+
+MoveRight:
+	INC cursor
+	LDA cursor
+	CMP #$10
+	BCC @done                    ; when greater skip
+	; wrap around
+	LDA #$00
+	STA cursor
+@done:                         ;
+	LDA #$00
+	STA next@input
+	STA RedrawTimeline
+	JMP MAIN
 
 ;; interface
 
+RedrawPlayer:
+	LDA position
+	ASL 
+	ASL 
+	ASL 
+	CLC 
+	ADC #$40
+	STA $0203                    ; set tile.x pos
+	RTS 
+
 RedrawMeter:
 	; selector
 	LDA #$04


@@ 108,82 249,97 @@ RedrawLine:
 	RTS 
 
 RedrawTimeline:
-	LDA #$10
-	LDX #$07
-	LDY #$22
+	LDX #$00
 @loop:                         ;
+	LDA #$22                     ; v pos
+	STA PPUADDR
+	LDA TimelinePositions, x     ; x pos
+	STA PPUADDR
+	LDA #$20
+	STA PPUDATA
 	INX 
-	JSR DrawAt
-	CPX #$18
+	CPX #$10
 	BNE @loop
 	RTS 
 
 Redraw:
+	LDA PPUSTATUS
 	JSR RedrawTimeline
 	JSR RedrawMeter
+	JSR RedrawPlayer
 	RTS 
 
 DrawAt:                        ; (a:id,x,y)
-	STY $2006
-	STX $2006
-	STA $2007
+	STY PPUADDR
+	STX PPUADDR
+	STA PPUDATA
 	RTS 
 
-LoadPalettes:                  ;
-	LDA $2002
-	LDA #$3F
-	STA $2006
-	LDA #$00
-	STA $2006
-	LDX #$00
-@loop:                         ;
-	LDA palettes, x
-	STA $2007
-	INX 
-	CPX #$20
-	BNE @loop
-	RTS 
+NMI:                           ;
 
-LoadAttributes:                ;
-	LDA $2002
-	LDA #$23
-	STA $2006
-	LDA #$C0
-	STA $2006
-	LDX #$00
-@loop:                         ;
-	LDA attributes, x
-	STA $2007
-	INX 
-	CPX #$40
-	BNE @loop
-	RTS 
+ReadJoy:
+	LDA #$01
+	STA JOY1                     ; start reading
+	STA down@input
+	LSR a
+	STA JOY1
+@loop:
+	LDA JOY1
+	LSR a
+	ROL down@input
+	BCC @loop
 
-NMI:                           ;
+SaveJoy:                       ; [skip]
+	LDA down@input
+	CMP last@input
+	BEQ @done
+	STA last@input
+	CMP #$00
+	BEQ @done
+	STA next@input
+@done:
 	LDA #$00
-	STA $2003                    ; set the low byte (00) of the RAM address
+	STA SPRADDR                  ; set the low byte (00) of the RAM address
 	LDA #$02
 	STA $4014                    ; set the high byte (02) of the RAM address, start the transfer
+
+RunTimer:
+	INC timer
+	; check if timer has reached rate
+	LDA timer
+	CMP rate
+	BNE @done
+	LDA #$00
+	STA timer
+	INC position
+	; check if position has reached 16
+	LDA position
+	CMP #$10
+	BNE @done
+	LDA #$00
+	STA position
+@done:
+
+Finish:
+	JSR Redraw
+@end:
+	LDA PPUSTATUS
+	LDA #$00                     ; No background scrolling
+	STA PPUSCROLL
+	STA PPUSCROLL
 	RTI                          ; return from interrupt
 
 ;; Tables
 
 	.org $E000
 
-attributes:                    ;
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-	.db %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000, %00000000
-
-palettes:                      ;
+Palettes:                      ;
 	.db $0F,$3B,$16,$30, $3B,$3B,$0F,$0F, $0F,$3B,$0F,$0F, $0F,$3B,$0F,$0F
 	.db $0F,$10,$17,$07, $0F,$3B,$0F,$0F, $0F,$0F,$0F,$0F, $0F,$0F,$0F,$0F
 
+TimelinePositions:
+	.db $08,$09,$0a,$0b,$0c,$0d,$0e,$0f,$10,$11,$12,$13,$14,$15,$16,$17
+
 ;; Vectors
 
 	.pad $FFFA

M src/sprite.chr => src/sprite.chr +0 -0

M zeropage.lua => zeropage.lua +1 -1

@@ 10,7 10,7 @@ end
 
 while true do
   for x=0,15 do 
-    for y=0,15 do 
+    for y=0,8 do 
       id = x + (y * 16)
       gui.text((x * 15) + 10, (y * 10) + 15, printaddr(id))
     end