background colors

This commit is contained in:
Tyrel Souza 2022-11-28 22:55:23 -05:00
parent e58a6330d9
commit db9827a299
4 changed files with 95 additions and 70 deletions

11
helloppu/consts.inc Executable file
View File

@ -0,0 +1,11 @@
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Constants for PPU registers mapped from addresses $2000 to $2007
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
PPU_CTRL = $2000
PPU_MASK = $2001
PPU_STATUS = $2002
OAM_ADDR = $2003
OAM_DATA = $2004
PPU_SCROLL = $2005
PPU_ADDR = $2006
PPU_DATA = $2007

13
helloppu/header.inc Normal file
View File

@ -0,0 +1,13 @@
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; The iNES header (contains a total of 16 bytes with the header flags)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.segment "HEADER"
.byte $4E,$45,$53,$1A ; 4 bytes with the characters 'N','E','S','\n'
.byte $02 ; How many 16KB of PRG-ROM we'll use (=32KB)
.byte $01 ; How many 8KB of CHR-ROM we'll use (=8KB)
.byte %00000000 ; Horz mirroring, no battery, mapper 0
.byte %00000000 ; mapper 0, playchoice, NES 2.0
.byte $00 ; No PRG-RAM
.byte $00 ; NTSC TV format
.byte $00 ; Extra flags for TV format and PRG-RAM
.byte $00,$00,$00,$00,$00 ; Unused padding to complete 16 bytes of header

View File

@ -1,99 +1,62 @@
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Constants for PPU registers mapped from addresses $2000 to $2007
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
PPU_CTRL = $2000
PPU_MASK = $2001
PPU_STATUS = $2002
OAM_ADDR = $2003
OAM_DATA = $2004
PPU_SCROLL = $2005
PPU_ADDR = $2006
PPU_DATA = $2007
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; The iNES header (contains a total of 16 bytes with the flags at $7F00)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.segment "HEADER"
.byte $4E,$45,$53,$1A ; 4 bytes with the characters 'N','E','S','\n'
.byte $02 ; How many 16KB of PRG-ROM we'll use (=32KB)
.byte $01 ; How many 8KB of CHR-ROM we'll use (=8KB)
.byte %00000000 ; Horz mirroring, no battery, mapper 0
.byte %00000000 ; mapper 0, playchoice, NES 2.0
.byte $00 ; No PRG-RAM
.byte $00 ; NTSC TV format
.byte $00 ; Extra flags for TV format and PRG-RAM
.byte $00,$00,$00,$00,$00 ; Unused padding to complete 16 bytes of header
.include "consts.inc"
.include "header.inc"
.include "reset.inc"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PRG-ROM code located at $8000
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.segment "CODE"
.proc LoadPalette
ldy #0
LoopPalette: ;unnamed label
lda PaletteData,y ; lookup byte in ROM
sta PPU_DATA ; set the value to send to PPU_DATA,
; will auto increment PPU_ADDR
iny
cpy #32
bne LoopPalette ; loop to previous label
rts ;return from subroutine
.endproc
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Reset handler (called when the NES resets or powers on)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Reset:
sei ; Disable all IRQ interrupts
cld ; Clear decimal mode (not supported by the NES)
ldx #$FF
txs ; Initialize the stack pointer at address $FF
inx ; Increment X, causing a rolloff from $FF to $00
stx PPU_CTRL ; disable NMI
stx PPU_MASK ; disable rendering
stx $4010 ; disable DMC IRQs
lda #$40
sta $4017 ; disable APU frame IRQ
Wait1stVBlank:
bit PPU_STATUS
bpl Wait1stVBlank
txa ; A = 0
ClearRAM:
sta $0000,x ; Zero RAM addresses from $0000 to $00FF
sta $0100,x ; Zero RAM addresses from $0100 to $01FF
sta $0200,x ; Zero RAM addresses from $0200 to $02FF
sta $0300,x ; Zero RAM addresses from $0300 to $03FF
sta $0400,x ; Zero RAM addresses from $0400 to $04FF
sta $0500,x ; Zero RAM addresses from $0500 to $05FF
sta $0600,x ; Zero RAM addresses from $0600 to $06FF
sta $0700,x ; Zero RAM addresses from $0700 to $07FF
inx
bne ClearRAM
Wait2ndVBlank:
bit PPU_STATUS
bpl Wait2ndVBlank ; bit-7 is 1
INIT_NES
Main:
ldx #$3F
stx PPU_ADDR
ldx #$00
stx PPU_ADDR
bit PPU_STATUS ; reset the latch
ldx #$3F
stx PPU_ADDR
ldx #$00
stx PPU_ADDR
lda #$25
sta PPU_DATA
jsr LoadPalette ;jump to subroutine
lda %00011110
sta PPU_MASK
lda #%00011110
sta PPU_MASK
LoopForever:
jmp LoopForever
jmp LoopForever
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; NMI interrupt handler
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
NMI:
rti ; Return from interrupt
rti ; Return from interrupt
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; IRQ interrupt handler
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
IRQ:
rti ; Return from interrupt
rti ; Return from interrupt
PaletteData:
.byte $0F,$2A,$0C,$3A, $0F,$2A,$0C,$3A, $0F,$2A,$0C,$3A, $0F,$2A,$0C,$3A ; background
.byte $0F,$10,$00,$26, $0F,$10,$00,$26, $0F,$10,$00,$26, $0F,$10,$00,$26 ; sprite
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Vectors with the addresses of the handlers that we always add at $FFFA

38
helloppu/reset.inc Normal file
View File

@ -0,0 +1,38 @@
.macro INIT_NES
sei ; Disable all IRQ interrupts
cld ; Clear decimal mode (not supported by the NES)
ldx #$FF
txs ; Initialize the stack pointer at address $FF
inx ; Increment X, causing a rolloff from $FF to $00
stx PPU_CTRL ; disable NMI
stx PPU_MASK ; disable rendering
stx $4010 ; disable DMC IRQs
lda #$40
sta $4017 ; disable APU frame IRQ
Wait1stVBlank:
bit PPU_STATUS
bpl Wait1stVBlank
txa ; A = 0
ClearRAM:
sta $0000,x ; Zero RAM addresses from $0000 to $00FF
sta $0100,x ; Zero RAM addresses from $0100 to $01FF
sta $0200,x ; Zero RAM addresses from $0200 to $02FF
sta $0300,x ; Zero RAM addresses from $0300 to $03FF
sta $0400,x ; Zero RAM addresses from $0400 to $04FF
sta $0500,x ; Zero RAM addresses from $0500 to $05FF
sta $0600,x ; Zero RAM addresses from $0600 to $06FF
sta $0700,x ; Zero RAM addresses from $0700 to $07FF
inx
bne ClearRAM
Wait2ndVBlank:
bit PPU_STATUS
bpl Wait2ndVBlank ; bit-7 is 1
.endmacro