millfork/include/nes_hardware.mfk

#if not(NES)
#warn nes_hardware module should be only used on NES/Famicom targets
#endif

volatile byte ppu_ctrl   @$2000
volatile byte ppu_mask   @$2001
volatile byte ppu_status @$2002
volatile byte oam_addr   @$2003
volatile byte oam_data   @$2004
volatile byte ppu_scroll @$2005
volatile byte ppu_addr   @$2006
volatile byte ppu_data   @$2007
volatile byte oam_dma    @$4014

// TODO: better names

volatile byte apu_pulse1_ctrl       @$4000
volatile byte apu_pulse1_sweep      @$4001
volatile word apu_pulse1_period     @$4002

volatile byte apu_pulse2_ctrl       @$4004
volatile byte apu_pulse2_sweep      @$4005
volatile word apu_pulse2_period     @$4006

volatile byte apu_triangle_unmute   @$4008
volatile word apu_triangle_period   @$400A

volatile byte apu_noise_ctrl        @$400C
volatile byte apu_noise_period      @$400E

volatile byte apu_dmc_ctrl          @$4010
volatile byte apu_dmc_load          @$4011
volatile byte apu_dmc_sample_addr   @$4012
volatile byte apu_dmc_sample_length @$4013

volatile byte apu_status            @$4015
volatile byte apu_frame_counter     @$4017

volatile byte joypad1_ctrl @$4016
volatile byte joypad2_ctrl @$4017

inline asm byte strobe_joypad() {
    ? LDA #1
    ! STA joypad1_ctrl
    ? LSR
    ! STA joypad1_ctrl
    ? RTS
}

inline asm byte read_joypad1() {
    ! LDA joypad1_ctrl
    ? RTS
}

inline asm byte read_joypad2() {
    ! LDA joypad2_ctrl
    ? RTS
}

macro asm void simulate_reset() {
    JMP (reset_vector.addr)
}

inline asm void ppu_set_addr(word register(ax) address) {
    ! STX ppu_addr
    ! STA ppu_addr
    ?RTS
}

inline asm byte read_ppu_status() {
    ! LDA ppu_status
    ? RTS
}

inline asm void ppu_set_scroll(byte register(a) xscroll, byte register(x) yscroll) {
    BIT ppu_status
    ! STA ppu_scroll
    ! STX ppu_scroll
    ? RTS
}

inline asm void ppu_write_data(byte register(a) data) {
    ! STA ppu_data
    ? RTS
}

inline asm void ppu_oam_dma_write(byte register(a) page) {
    ! STA oam_dma
    ? RTS
}