243 lines
7.2 KiB
Zig
243 lines
7.2 KiB
Zig
const std = @import("std");
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const Bit = @import("bitfield").Bit;
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const Bitfield = @import("bitfield").Bitfield;
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const Bus = @import("../Bus.zig");
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const log = std.log.scoped(.@"I/O");
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pub const Io = struct {
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const Self = @This();
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/// Read / Write
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ime: bool,
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ie: InterruptEnable,
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irq: InterruptRequest,
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postflg: PostFlag,
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is_halted: bool,
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keyinput: KeyInput,
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pub fn init() Self {
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return .{
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.ime = false,
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.ie = .{ .raw = 0x0000 },
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.irq = .{ .raw = 0x0000 },
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.postflg = .{ .raw = 0x00 },
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.keyinput = .{ .raw = 0x03FF },
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.is_halted = false,
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};
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}
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};
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pub fn read32(bus: *const Bus, addr: u32) u32 {
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return switch (addr) {
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0x0400_0000 => bus.ppu.dispcnt.raw,
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0x0400_0004 => bus.ppu.dispstat.raw,
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0x0400_0006 => bus.ppu.vcount.raw,
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0x0400_0200 => bus.io.ie.raw,
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0x0400_0208 => @boolToInt(bus.io.ime),
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else => std.debug.panic("Tried to read from {X:0>8}", .{addr}),
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};
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}
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pub fn write32(bus: *Bus, addr: u32, word: u32) void {
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switch (addr) {
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0x0400_0000 => bus.ppu.dispcnt.raw = @truncate(u16, word),
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0x0400_0004 => {
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bus.ppu.dispstat.raw = @truncate(u16, word);
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bus.ppu.vcount.raw = @truncate(u16, word >> 16);
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},
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0x0400_0008 => {
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bus.ppu.bg[0].cnt.raw = @truncate(u16, word);
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bus.ppu.bg[1].cnt.raw = @truncate(u16, word >> 16);
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},
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0x0400_000C => {
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bus.ppu.bg[2].cnt.raw = @truncate(u16, word);
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bus.ppu.bg[3].cnt.raw = @truncate(u16, word >> 16);
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},
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0x0400_0010 => {
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bus.ppu.bg[0].hofs.raw = @truncate(u16, word);
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bus.ppu.bg[0].vofs.raw = @truncate(u16, word >> 16);
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},
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0x0400_0014 => {
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bus.ppu.bg[1].hofs.raw = @truncate(u16, word);
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bus.ppu.bg[1].vofs.raw = @truncate(u16, word >> 16);
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},
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0x0400_0018 => {
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bus.ppu.bg[2].hofs.raw = @truncate(u16, word);
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bus.ppu.bg[2].vofs.raw = @truncate(u16, word >> 16);
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},
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0x0400_001C => {
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bus.ppu.bg[3].hofs.raw = @truncate(u16, word);
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bus.ppu.bg[3].vofs.raw = @truncate(u16, word >> 16);
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},
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0x0400_0200 => bus.io.ie.raw = @truncate(u16, word),
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0x0400_0204 => log.warn("Wrote 0x{X:0>8} to WAITCNT", .{word}),
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0x0400_0208 => bus.io.ime = word & 1 == 1,
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else => std.debug.panic("Tried to write 0x{X:0>8} to 0x{X:0>8}", .{ word, addr }),
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}
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}
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pub fn read16(bus: *const Bus, addr: u32) u16 {
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return switch (addr) {
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0x0400_0000 => bus.ppu.dispcnt.raw,
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0x0400_0004 => bus.ppu.dispstat.raw,
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0x0400_0006 => bus.ppu.vcount.raw,
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0x0400_0130 => bus.io.keyinput.raw,
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0x0400_0200 => bus.io.ie.raw,
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0x0400_0208 => @boolToInt(bus.io.ime),
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else => std.debug.panic("Tried to read from {X:0>4}", .{addr}),
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};
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}
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pub fn write16(bus: *Bus, addr: u32, halfword: u16) void {
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switch (addr) {
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0x0400_0000 => bus.ppu.dispcnt.raw = halfword,
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0x0400_0004 => bus.ppu.dispstat.raw = halfword,
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0x0400_0008...0x0400_000F => bus.ppu.bg[addr & 0x7].cnt.raw = halfword,
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0x0400_0010 => bus.ppu.bg[0].hofs.raw = halfword, // TODO: Don't write out every HOFS / VOFS?
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0x0400_0012 => bus.ppu.bg[0].vofs.raw = halfword,
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0x0400_0014 => bus.ppu.bg[1].hofs.raw = halfword,
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0x0400_0016 => bus.ppu.bg[1].vofs.raw = halfword,
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0x0400_0018 => bus.ppu.bg[2].hofs.raw = halfword,
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0x0400_001A => bus.ppu.bg[2].vofs.raw = halfword,
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0x0400_001C => bus.ppu.bg[3].hofs.raw = halfword,
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0x0400_001E => bus.ppu.bg[3].vofs.raw = halfword,
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0x0400_0200 => bus.io.ie.raw = halfword,
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0x0400_0202 => bus.io.irq.raw &= ~halfword,
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0x0400_0208 => bus.io.ime = halfword & 1 == 1,
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else => std.debug.panic("Tried to write 0x{X:0>4} to 0x{X:0>8}", .{ halfword, addr }),
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}
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}
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pub fn read8(bus: *const Bus, addr: u32) u8 {
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return switch (addr) {
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0x0400_0000 => @truncate(u8, bus.ppu.dispcnt.raw),
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0x0400_0004 => @truncate(u8, bus.ppu.dispstat.raw),
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0x0400_0200 => @truncate(u8, bus.io.ie.raw),
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0x0400_0300 => bus.io.postflg.raw,
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0x0400_0006 => @truncate(u8, bus.ppu.vcount.raw),
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else => std.debug.panic("Tried to read from 0x{X:0>8}", .{addr}),
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};
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}
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pub fn write8(self: *Bus, addr: u32, byte: u8) void {
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switch (addr) {
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0x0400_0208 => self.io.ime = byte & 1 == 1,
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0x0400_0301 => self.io.is_halted = byte >> 7 & 1 == 0, // TODO: Implement Stop?
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else => std.debug.panic("Tried to write 0x{X:0>2} to 0x{X:0>8}", .{ byte, addr }),
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}
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}
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/// Read / Write
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pub const PostFlag = extern union {
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/// 0 if First Boot, 1 if a Reset has been done
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not_first_boot: Bit(u8, 0),
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raw: u8,
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};
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/// Read / Write
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pub const DisplayControl = extern union {
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bg_mode: Bitfield(u16, 0, 3),
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frame_select: Bit(u16, 4),
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hblank_interval_free: Bit(u16, 5),
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obj_mapping: Bit(u16, 6),
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forced_blank: Bit(u16, 7),
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bg_enable: Bitfield(u16, 8, 4),
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obj_enable: Bit(u16, 12),
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win_enable: Bitfield(u16, 13, 2),
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obj_win_enable: Bit(u16, 15),
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raw: u16,
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};
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/// Read / Write
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pub const DisplayStatus = extern union {
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vblank: Bit(u16, 0),
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hblank: Bit(u16, 1),
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coincidence: Bit(u16, 2),
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vblank_irq: Bit(u16, 3),
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hblank_irq: Bit(u16, 4),
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vcount_irq: Bit(u16, 5),
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vcount_trigger: Bitfield(u16, 8, 8),
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raw: u16,
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};
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/// Read Only
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pub const VCount = extern union {
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scanline: Bitfield(u16, 0, 8),
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raw: u16,
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};
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/// Read / Write
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const InterruptEnable = extern union {
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vblank: Bit(u16, 0),
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hblank: Bit(u16, 1),
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coincidence: Bit(u16, 2),
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tm0_overflow: Bit(u16, 3),
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tm1_overflow: Bit(u16, 4),
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tm2_overflow: Bit(u16, 5),
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tm3_overflow: Bit(u16, 6),
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serial: Bit(u16, 7),
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dma0: Bit(u16, 8),
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dma1: Bit(u16, 9),
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dma2: Bit(u16, 10),
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dma3: Bit(u16, 11),
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keypad: Bit(u16, 12),
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game_pak: Bit(u16, 13),
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raw: u16,
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};
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/// Read Only
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/// 0 = Pressed, 1 = Released
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const KeyInput = extern union {
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a: Bit(u16, 0),
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b: Bit(u16, 1),
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select: Bit(u16, 2),
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start: Bit(u16, 3),
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right: Bit(u16, 4),
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left: Bit(u16, 5),
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up: Bit(u16, 6),
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down: Bit(u16, 7),
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shoulder_r: Bit(u16, 8),
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shoulder_l: Bit(u16, 9),
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raw: u16,
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};
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// Read / Write
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pub const BackgroundControl = extern union {
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priority: Bitfield(u16, 0, 2),
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char_base: Bitfield(u16, 2, 2),
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mosaic_enable: Bit(u16, 6),
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colour_mode: Bit(u16, 7),
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screen_base: Bitfield(u16, 8, 5),
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display_overflow: Bit(u16, 13),
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size: Bitfield(u16, 14, 2),
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raw: u16,
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};
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/// Write Only
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pub const BackgroundOffset = extern union {
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offset: Bitfield(u16, 0, 9),
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raw: u16,
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};
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/// Read / Write
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const InterruptRequest = extern union {
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vblank: Bit(u16, 0),
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hblank: Bit(u16, 1),
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coincidence: Bit(u16, 2),
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tim0_overflow: Bit(u16, 3),
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tim1_overflow: Bit(u16, 4),
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tim2_overflow: Bit(u16, 5),
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tim3_overflow: Bit(u16, 6),
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serial: Bit(u16, 7),
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dma0: Bit(u16, 8),
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dma1: Bit(u16, 9),
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dma2: Bit(u16, 10),
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dma3: Bit(u16, 11),
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keypad: Bit(u16, 12),
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game_pak: Bit(u16, 13),
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raw: u16,
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};
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