mirror of
https://github.com/cc65/cc65.git
synced 2024-11-01 11:04:34 +00:00
159 lines
5.9 KiB
ArmAsm
159 lines
5.9 KiB
ArmAsm
;
|
|
; Written by Groepaz/Hitmen <groepaz@gmx.net>
|
|
; Cleanup by Ullrich von Bassewitz <uz@cc65.org>
|
|
;
|
|
|
|
.export ppuinit
|
|
.export paletteinit, paldata
|
|
|
|
.include "nes.inc"
|
|
|
|
;+---------+----------------------------------------------------------+
|
|
;| $2000 | PPU Control Register #1 (W) |
|
|
;| | |
|
|
;| | D7: Execute NMI on VBlank |
|
|
;| | 0 = Disabled |
|
|
;| | 1 = Enabled |
|
|
;| | D6: PPU Master/Slave Selection --+ |
|
|
;| | 0 = Master +-- UNUSED |
|
|
;| | 1 = Slave --+ |
|
|
;| | D5: Sprite Size |
|
|
;| | 0 = 8x8 |
|
|
;| | 1 = 8x16 |
|
|
;| | D4: Background Pattern Table Address |
|
|
;| | 0 = $0000 (VRAM) |
|
|
;| | 1 = $1000 (VRAM) |
|
|
;| | D3: Sprite Pattern Table Address |
|
|
;| | 0 = $0000 (VRAM) |
|
|
;| | 1 = $1000 (VRAM) |
|
|
;| | D2: PPU Address Increment |
|
|
;| | 0 = Increment by 1 |
|
|
;| | 1 = Increment by 32 |
|
|
;| | D1-D0: Name Table Address |
|
|
;| | 00 = $2000 (VRAM) |
|
|
;| | 01 = $2400 (VRAM) |
|
|
;| | 10 = $2800 (VRAM) |
|
|
;| | 11 = $2C00 (VRAM) |
|
|
;+---------+----------------------------------------------------------+
|
|
;+---------+----------------------------------------------------------+
|
|
;| $2001 | PPU Control Register #2 (W) |
|
|
;| | |
|
|
;| | D7-D5: Full Background Colour (when D0 == 1) |
|
|
;| | 000 = None +------------+ |
|
|
;| | 001 = Green | NOTE: Do not use more |
|
|
;| | 010 = Blue | than one type |
|
|
;| | 100 = Red +------------+ |
|
|
;| | D7-D5: Colour Intensity (when D0 == 0) |
|
|
;| | 000 = None +--+ |
|
|
;| | 001 = Intensify green | NOTE: Do not use more |
|
|
;| | 010 = Intensify blue | than one type |
|
|
;| | 100 = Intensify red +--+ |
|
|
;| | D4: Sprite Visibility |
|
|
;| | 0 = Sprites not displayed |
|
|
;| | 1 = Sprites visible |
|
|
;| | D3: Background Visibility |
|
|
;| | 0 = Background not displayed |
|
|
;| | 1 = Background visible |
|
|
;| | D2: Sprite Clipping |
|
|
;| | 0 = Sprites invisible in left 8-pixel column |
|
|
;| | 1 = No clipping |
|
|
;| | D1: Background Clipping |
|
|
;| | 0 = BG invisible in left 8-pixel column |
|
|
;| | 1 = No clipping |
|
|
;| | D0: Display Type |
|
|
;| | 0 = Colour display |
|
|
;| | 1 = Monochrome display |
|
|
;+---------+----------------------------------------------------------+
|
|
|
|
|
|
;-----------------------------------------------------------------------------
|
|
|
|
.segment "ONCE"
|
|
|
|
.proc ppuinit
|
|
|
|
lda #%10101000
|
|
sta PPU_CTRL1
|
|
|
|
lda #%00011110
|
|
sta PPU_CTRL2
|
|
|
|
; Wait for vblank
|
|
|
|
@wait: lda PPU_STATUS
|
|
bpl @wait
|
|
|
|
; reset scrolling
|
|
|
|
lda #0
|
|
sta PPU_VRAM_ADDR1
|
|
sta PPU_VRAM_ADDR1
|
|
|
|
; Make all sprites invisible
|
|
|
|
lda #$00
|
|
ldy #$f0
|
|
sta PPU_SPR_ADDR
|
|
ldx #$40
|
|
@loop: sty PPU_SPR_IO
|
|
sta PPU_SPR_IO
|
|
sta PPU_SPR_IO
|
|
sty PPU_SPR_IO
|
|
dex
|
|
bne @loop
|
|
|
|
rts
|
|
|
|
.endproc
|
|
|
|
;-----------------------------------------------------------------------------
|
|
|
|
.proc paletteinit
|
|
|
|
; Wait for v-blank
|
|
@wait: lda PPU_STATUS
|
|
bpl @wait
|
|
|
|
lda #$3F
|
|
sta PPU_VRAM_ADDR2
|
|
lda #$00
|
|
sta PPU_VRAM_ADDR2
|
|
|
|
ldx #0
|
|
@loop: lda paldata,x
|
|
sta PPU_VRAM_IO
|
|
inx
|
|
cpx #(16*2)
|
|
bne @loop
|
|
|
|
rts
|
|
|
|
.endproc
|
|
|
|
;-----------------------------------------------------------------------------
|
|
|
|
.rodata
|
|
|
|
paldata:
|
|
.repeat 2
|
|
.byte $0f ; 0 black
|
|
.byte $14 ; 4 violet
|
|
.byte $3b ; 3 cyan
|
|
.byte $3d ; 1 white
|
|
|
|
.byte $38 ; 7 yellow
|
|
.byte $2d ; b dark grey
|
|
.byte $22 ; e light blue
|
|
.byte $04 ; 2 red
|
|
|
|
.byte $18 ; 8 orange
|
|
.byte $08 ; 9 brown
|
|
.byte $35 ; a light red
|
|
.byte $01 ; 6 blue
|
|
|
|
.byte $10 ; c middle grey
|
|
.byte $2b ; d light green
|
|
.byte $3d ; f light gray
|
|
.byte $1a ; 5 green
|
|
.endrepeat
|