feat(ppu): introduce concept of 2 graphics engines + refactor

This commit is contained in:
Rekai Nyangadzayi Musuka 2023-11-03 23:14:32 -05:00
parent 13f5497808
commit 16b3325fe3
8 changed files with 479 additions and 373 deletions

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@ -66,7 +66,7 @@ pub fn handle(self: *@This(), bus_ptr: ?*anyopaque, event: Event, late: u64) voi
bus.ppu.onHdrawEnd(self, late);
},
.hblank => bus.ppu.onHblankEnd(self, late),
.vblank => bus.ppu.onHblankEnd(self, late),
.vblank => bus.ppu.onVblankEnd(self, late),
.sqrt => bus.io.sqrt.onSqrtCalc(),
.div => bus.io.div.onDivCalc(),
}

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@ -132,7 +132,7 @@ pub const SharedCtx = struct {
const KiB = 0x400;
pub const Io = @import("io.zig").Io;
const Vram = @import("ppu.zig").Vram;
const Vram = @import("ppu/Vram.zig");
io: *Io,
main: *[4 * MiB]u8,

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@ -4,7 +4,7 @@ const io = @import("io.zig");
const Scheduler = @import("../Scheduler.zig");
const SharedCtx = @import("../emu.zig").SharedCtx;
const Wram = @import("../emu.zig").Wram;
const Vram = @import("../ppu.zig").Vram;
const Vram = @import("../ppu/Vram.zig");
const Bios = @import("Bios.zig");
const forceAlign = @import("../emu.zig").forceAlign;

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@ -2,7 +2,7 @@ const std = @import("std");
const log = std.log.scoped(.cp15);
const panic_on_unimplemented: bool = true;
const panic_on_unimplemented: bool = false;
control: u32 = 0x0005_2078,
dtcm_size_base: u32 = 0x0300_000A,

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@ -34,10 +34,6 @@ pub const Io = struct {
/// Caller must cast the `u32` to either `nds7.IntRequest` or `nds9.IntRequest`
irq: IntRequest = .{ .raw = 0x0000_0000 },
/// POWCNT1 - Graphics Power Control
/// Read / Write
powcnt: PowCnt = .{ .raw = 0x0000_0000 },
// Read Only
keyinput: AtomicKeyInput = .{},
@ -82,7 +78,7 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) T {
// Timers
0x0400_0100...0x0400_010E => warn("TODO: impl timer", .{}),
0x0400_0004 => bus.ppu.io.dispstat.raw,
0x0400_0004 => bus.ppu.engines[0].dispstat.raw,
0x0400_0130 => bus.io.keyinput.load(.Monotonic),
0x0400_0180 => @truncate(bus.io.shr.ipc._nds9.sync.raw),
@ -120,7 +116,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
// Timers
0x0400_0100...0x0400_010C => log.warn("TODO: impl timer", .{}),
0x0400_0000 => bus.ppu.io.dispcnt_a.raw = value,
0x0400_0000 => bus.ppu.engines[0].dispcnt.raw = value,
0x0400_0180 => bus.io.shr.ipc.setIpcSync(.nds9, value),
0x0400_0184 => bus.io.shr.ipc.setIpcFifoCnt(.nds9, value),
0x0400_0188 => bus.io.shr.ipc.send(.nds9, value),
@ -151,7 +147,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
bus.io.sqrt.schedule(bus.scheduler);
},
0x0400_0304 => bus.io.powcnt.raw = value,
0x0400_0304 => bus.ppu.io.powcnt.raw = value,
else => log.warn("unexpected: write(T: {}, addr: 0x{X:0>8}, value: 0x{X:0>8})", .{ T, address, value }),
},
@ -177,7 +173,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
bus.io.sqrt.schedule(bus.scheduler);
},
0x0400_0304 => bus.io.powcnt.raw = value,
0x0400_0304 => bus.ppu.io.powcnt.raw = value,
else => log.warn("unexpected: write(T: {}, addr: 0x{X:0>8}, value: 0x{X:0>4})", .{ T, address, value }),
},
@ -241,7 +237,7 @@ fn warn(comptime format: []const u8, args: anytype) u0 {
return 0;
}
const PowCnt = extern union {
pub const PowCnt = extern union {
// Enable flag for both LCDs
lcd: Bit(u32, 0),
engine2d_a: Bit(u32, 1),
@ -382,8 +378,7 @@ const SquareRootUnit = struct {
};
pub const DispcntA = extern union {
bg_mode: Bitfield(u32, 0, 2),
bg_mode: Bitfield(u32, 0, 3),
/// toggle between 2D and 3D for BG0
bg0_dimension: Bit(u32, 3),
tile_obj_mapping: Bit(u32, 4),
@ -400,7 +395,25 @@ pub const DispcntA = extern union {
bitmap_obj_1d_boundary: Bit(u32, 22),
obj_during_hblank: Bit(u32, 23),
character_base: Bitfield(u32, 24, 3),
screen_base: Bitfield(u32, 27, 2),
screen_base: Bitfield(u32, 27, 3),
bg_ext_pal_enable: Bit(u32, 30),
obj_ext_pal_enable: Bit(u32, 31),
raw: u32,
};
pub const DispcntB = extern union {
bg_mode: Bitfield(u32, 0, 3),
tile_obj_mapping: Bit(u32, 4),
bitmap_obj_2d_dimension: Bit(u32, 5),
bitmap_obj_mapping: Bit(u32, 6),
forced_blank: Bit(u32, 7),
bg_enable: Bitfield(u32, 8, 4),
obj_enable: Bit(u32, 12),
win_enable: Bitfield(u32, 13, 2),
obj_win_enable: Bit(u32, 15),
display_mode: Bitfield(u32, 16, 2),
tile_obj_1d_boundary: Bitfield(u32, 20, 2),
obj_during_hblank: Bit(u32, 23),
bg_ext_pal_enable: Bit(u32, 30),
obj_ext_pal_enable: Bit(u32, 31),
raw: u32,

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@ -4,6 +4,10 @@ const Allocator = std.mem.Allocator;
const Scheduler = @import("Scheduler.zig");
const System = @import("emu.zig").System;
const Vram = @import("ppu/Vram.zig");
const EngineA = @import("ppu/engine.zig").EngineA;
const EngineB = @import("ppu/engine.zig").EngineB;
pub const screen_width = 256;
pub const screen_height = 192;
const KiB = 0x400;
@ -15,18 +19,14 @@ pub const Ppu = struct {
vram: *Vram,
engines: struct { EngineA, EngineB } = .{ .{}, .{} },
io: Io = .{},
const Io = struct {
const nds9 = @import("nds9/io.zig");
const types = @import("nds9/io.zig");
/// Read / Write
dispcnt_a: nds9.DispcntA = .{ .raw = 0x0000_0000 },
/// Read / Write
dispstat: nds9.Dispstat = .{ .raw = 0x0000 },
/// Read-Only
vcount: nds9.Vcount = .{ .raw = 0x0000 },
powcnt: types.PowCnt = .{ .raw = 0x0000_0000 },
};
pub fn init(allocator: Allocator, vram: *Vram) !@This() {
@ -41,64 +41,69 @@ pub const Ppu = struct {
}
pub fn drawScanline(self: *@This(), bus: *System.Bus9) void {
const bg_mode = self.io.dispcnt_a.display_mode.read();
const scanline = self.io.vcount.scanline.read();
if (self.io.powcnt.engine2d_a.read())
self.engines[0].drawScanline(bus, &self.fb, &self.io.powcnt);
switch (bg_mode) {
0x0 => {},
0x1 => {},
0x2 => {
// Draw Top Screen
{
const buf = self.fb.top(.back);
const ptr: *[screen_width * screen_height]u32 = @ptrCast(@alignCast(buf.ptr));
const scanline_ptr = ptr[screen_width * @as(u32, scanline) ..][0..screen_width];
const base_addr: u32 = 0x0680_0000 + (screen_width * @sizeOf(u16)) * @as(u32, scanline);
// FIXME: I don't think it's okay to be accessing the ARM9 Bus instead of just working with
// memory directly. However, I do understand that VRAM-A, VRAM-B might change things
for (scanline_ptr, 0..) |*rgba, i| {
const addr = base_addr + @as(u32, @intCast(i)) * @sizeOf(u16);
rgba.* = rgba888(bus.dbgRead(u16, addr));
}
}
},
0x3 => {},
}
if (self.io.powcnt.engine2d_b.read())
self.engines[1].drawScanline(bus, &self.fb, &self.io.powcnt);
}
/// HDraw -> HBlank
pub fn onHdrawEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
const dots_in_hblank = 99;
std.debug.assert(self.io.dispstat.hblank.read() == false);
std.debug.assert(self.io.dispstat.vblank.read() == false);
inline for (&self.engines) |*engine| {
std.debug.assert(engine.dispstat.hblank.read() == false);
std.debug.assert(engine.dispstat.vblank.read() == false);
// TODO: Signal HBlank IRQ
self.io.dispstat.hblank.set();
engine.dispstat.hblank.set();
}
const dots_in_hblank = 99;
scheduler.push(.{ .nds9 = .hblank }, dots_in_hblank * cycles_per_dot -| late);
}
// VBlank -> HBlank (Still VBlank)
pub fn onVblankEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
inline for (&self.engines) |*engine| {
std.debug.assert(!engine.dispstat.hblank.read());
std.debug.assert(engine.vcount.scanline.read() == 262 or engine.dispstat.vblank.read());
// TODO: Signal HBlank IRQ
engine.dispstat.hblank.set();
}
const dots_in_hblank = 99;
scheduler.push(.{ .nds9 = .hblank }, dots_in_hblank * cycles_per_dot -| late);
}
/// HBlank -> HDraw / VBlank
pub fn onHblankEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
const scanline_count = 192 + 71;
const scanline_total = 263; // 192 visible, 71 blanking
const prev_scanline = self.io.vcount.scanline.read();
const scanline = (prev_scanline + 1) % scanline_count;
std.debug.assert(self.engines[0].vcount.scanline.read() == self.engines[1].vcount.scanline.read());
self.io.vcount.scanline.write(scanline);
self.io.dispstat.hblank.unset();
inline for (&self.engines) |*engine| {
const prev_scanline = engine.vcount.scanline.read();
const scanline = (prev_scanline + 1) % scanline_total;
const coincidence = scanline == self.io.dispstat.lyc.read();
self.io.dispstat.coincidence.write(coincidence);
engine.vcount.scanline.write(scanline);
engine.dispstat.hblank.unset();
const coincidence = scanline == engine.dispstat.lyc.read();
engine.dispstat.coincidence.write(coincidence);
}
const scanline = self.engines[0].vcount.scanline.read();
// TODO: LYC == LY IRQ
if (scanline < 192) {
std.debug.assert(self.io.dispstat.vblank.read() == false);
std.debug.assert(self.io.dispstat.hblank.read() == false);
inline for (&self.engines) |*engine| {
std.debug.assert(engine.dispstat.vblank.read() == false);
std.debug.assert(engine.dispstat.hblank.read() == false);
}
// Draw Another Scanline
const dots_in_hdraw = 256;
@ -108,16 +113,22 @@ pub const Ppu = struct {
if (scanline == 192) {
// Transition from Hblank to Vblank
self.fb.swap();
self.io.dispstat.vblank.set();
inline for (&self.engines) |*engine|
engine.dispstat.vblank.set();
// TODO: Signal VBlank IRQ
}
if (scanline == 262) self.io.dispstat.vblank.unset();
std.debug.assert(self.io.dispstat.vblank.read() == (scanline != 262));
if (scanline == 262) {
inline for (&self.engines) |*engine| {
engine.dispstat.vblank.unset();
std.debug.assert(engine.dispstat.vblank.read() == (scanline != 262));
}
}
const dots_in_scanline = 256 + 99;
scheduler.push(.{ .nds9 = .hblank }, dots_in_scanline * cycles_per_dot -| late);
const dots_in_vblank = 256;
scheduler.push(.{ .nds9 = .vblank }, dots_in_vblank * cycles_per_dot -| late);
}
};
@ -126,15 +137,15 @@ pub const FrameBuffer = struct {
current: u1 = 0,
ptr: *[len * 4]u8,
ptr: *align(@sizeOf(u32)) [len * 4]u8,
const Position = enum { top, bottom };
const Layer = enum { front, back };
pub fn init(allocator: Allocator) !@This() {
const ptr = try allocator.create([len * 4]u8);
const buf = try allocator.alignedAlloc(u8, @sizeOf(u32), len * 4);
return .{ .ptr = ptr };
return .{ .ptr = buf[0 .. len * 4] };
}
pub fn deinit(self: @This(), allocator: Allocator) void {
@ -162,303 +173,3 @@ pub const FrameBuffer = struct {
return self.get(.bottom, layer);
}
};
inline fn rgba888(bgr555: u16) u32 {
const b: u32 = bgr555 >> 10 & 0x1F;
const g: u32 = bgr555 >> 5 & 0x1F;
const r: u32 = bgr555 & 0x1F;
// zig fmt: off
return (r << 3 | r >> 2) << 24
| (g << 3 | g >> 2) << 16
| (b << 3 | b >> 2) << 8
| 0xFF;
// zig fmt: on
}
pub const Vram = struct {
const page_size = 16 * KiB; // smallest allocation is 16 KiB
const addr_space_size = 0x0100_0000; // 0x0600_0000 -> 0x06FF_FFFF (inclusive)
const table_len = addr_space_size / page_size;
const buf_len = 656 * KiB;
const IntFittingRange = std.math.IntFittingRange;
const log = std.log.scoped(.vram);
io: Io = .{},
_buf: *[buf_len]u8,
nds9_table: *const [table_len]?[*]u8,
nds7_table: *const [table_len]?[*]u8,
const Io = struct {
const nds9 = @import("nds9/io.zig");
const nds7 = @import("nds7/io.zig");
pub const Vramstat = @import("nds7/io.zig").Vramstat;
stat: nds7.Vramstat = .{ .raw = 0x00 },
/// Write-Only (according to melonDS these are readable lol)
cnt_a: nds9.Vramcnt.A = .{ .raw = 0x00 },
cnt_b: nds9.Vramcnt.A = .{ .raw = 0x00 },
cnt_c: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_d: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_e: nds9.Vramcnt.E = .{ .raw = 0x00 },
cnt_f: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_g: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_h: nds9.Vramcnt.H = .{ .raw = 0x00 },
cnt_i: nds9.Vramcnt.H = .{ .raw = 0x00 },
};
pub fn init(self: *@This(), allocator: Allocator) !void {
const buf = try allocator.create([buf_len]u8);
errdefer allocator.destroy(buf);
@memset(buf, 0);
const tables = try allocator.alloc(?[*]u8, 2 * table_len);
@memset(tables, null);
self.* = .{
.nds9_table = tables[0..table_len],
.nds7_table = tables[table_len .. 2 * table_len],
._buf = buf,
};
// ROMS like redpanda.nds won't write to VRAMCNT before trying to write to VRAM
// therefore we assume some default allocation (in this casee VRAMCNT_A -> VRAMCNT_I are 0x00)
self.update();
}
pub fn deinit(self: @This(), allocator: Allocator) void {
allocator.destroy(self._buf);
const ptr: [*]?[*]const u8 = @ptrCast(@constCast(self.nds9_table));
allocator.free(ptr[0 .. 2 * table_len]);
}
pub fn stat(self: *const @This()) Io.Vramstat {
const vram_c: u8 = @intFromBool(self.io.cnt_c.enable.read() and self.io.cnt_c.mst.read() == 2);
const vram_d: u8 = @intFromBool(self.io.cnt_d.enable.read() and self.io.cnt_d.mst.read() == 2);
return .{ .raw = (vram_d << 1) | vram_c };
}
const Kind = enum {
a,
b,
c,
d,
e,
f,
g,
h,
i,
/// In Bytes
inline fn size(self: @This()) u32 {
return switch (self) {
.a => 128 * KiB,
.b => 128 * KiB,
.c => 128 * KiB,
.d => 128 * KiB,
.e => 64 * KiB,
.f => 16 * KiB,
.g => 16 * KiB,
.h => 32 * KiB,
.i => 16 * KiB,
};
}
};
// TODO: Rename
fn range(comptime kind: Kind, mst: u3, offset: u2) u32 {
const ofs: u32 = offset;
// panic messages are from GBATEK
return switch (kind) {
.a => switch (mst) {
0 => 0x0680_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0640_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_A: Slot OFS(0-3)"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.b => switch (mst) {
0 => 0x0682_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0640_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_B: Slot OFS(0-3)"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.c => switch (mst) {
0 => 0x0684_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0600_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_C: Slot OFS(0-3)"),
4 => 0x0620_0000,
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.d => switch (mst) {
0 => 0x0686_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0600_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_D: Slot OFS(0-3)"),
4 => 0x0660_0000,
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.e => switch (mst) {
0 => 0x0688_0000,
1 => 0x0600_0000,
2 => 0x0640_0000,
3 => @panic("VRAMCNT_E: Slots 0-3"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.f => switch (mst) {
0 => 0x0689_0000,
1 => 0x0600_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
2 => 0x0640_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
3 => @panic("VRAMCNT_F: Slot (OFS.0*1)+(OFS.1*4)"),
4 => @panic("VRAMCNT_F: Slot 0-1 (OFS=0), Slot 2-3 (OFS=1)"),
5 => @panic("VRAMCNT_F: Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.g => switch (mst) {
0 => 0x0689_4000,
1 => 0x0600_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
2 => 0x0640_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
3 => @panic("VRAMCNT_G: Slot (OFS.0*1)+(OFS.1*4)"),
4 => @panic("VRAMCNT_G: Slot 0-1 (OFS=0), Slot 2-3 (OFS=1)"),
5 => @panic("VRAMCNT_G: Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.h => switch (mst) {
0 => 0x0689_8000,
1 => 0x0620_0000,
2 => @panic("VRAMCNT_H: Slot 0-3"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.i => switch (mst) {
0 => 0x068A_0000,
1 => 0x0620_8000,
2 => 0x0660_0000,
3 => @panic("Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
};
}
fn buf_offset(comptime kind: Kind) usize {
// zig fmt: off
return switch (kind) {
.a => 0, // 0x00000
.b => (128 * KiB) * 1, // 0x20000 (+ 0x20000)
.c => (128 * KiB) * 2, // 0x40000 (+ 0x20000)
.d => (128 * KiB) * 3, // 0x60000 (+ 0x20000)
.e => (128 * KiB) * 4, // 0x80000 (+ 0x20000)
.f => (128 * KiB) * 4 + (64 * KiB), // 0x90000 (+ 0x10000)
.g => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 1, // 0x94000 (+ 0x04000)
.h => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 2, // 0x98000 (+ 0x04000)
.i => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 2 + (32 * KiB) // 0xA0000 (+ 0x08000)
};
// zig fmt: on
}
fn CntType(comptime kind: Kind) type {
const io = @import("nds9/io.zig");
return switch (kind) {
.a => io.Vramcnt.A,
.b => io.Vramcnt.A,
.c => io.Vramcnt.C,
.d => io.Vramcnt.C,
.e => io.Vramcnt.E,
.f => io.Vramcnt.C,
.g => io.Vramcnt.C,
.h => io.Vramcnt.H,
.i => io.Vramcnt.H,
};
}
fn cntValue(self: *const @This(), comptime kind: Kind) CntType(kind) {
return switch (kind) {
.a => self.io.cnt_a,
.b => self.io.cnt_b,
.c => self.io.cnt_c,
.d => self.io.cnt_d,
.e => self.io.cnt_e,
.f => self.io.cnt_f,
.g => self.io.cnt_g,
.h => self.io.cnt_h,
.i => self.io.cnt_i,
};
}
// TODO: We always update the entirety of VRAM when that argubably isn't necessary
pub fn update(self: *@This()) void {
const nds9_tbl = @constCast(self.nds9_table);
const nds7_tbl = @constCast(self.nds7_table);
for (nds9_tbl, nds7_tbl, 0..) |*nds9_ptr, *nds7_ptr, i| {
const addr = 0x0600_0000 + (i * page_size);
inline for (std.meta.fields(Kind)) |f| {
const kind = @field(Kind, f.name);
const cnt = cntValue(self, kind);
const ofs = switch (kind) {
.e, .h, .i => 0,
else => cnt.offset.read(),
};
const min = range(kind, cnt.mst.read(), ofs);
const max = min + kind.size();
const offset = addr & (kind.size() - 1);
if (min <= addr and addr < max) {
if ((kind == .c or kind == .d) and cnt.mst.read() == 2) {
// Allocate to ARM7
nds7_ptr.* = self._buf[buf_offset(kind) + offset ..].ptr;
} else {
nds9_ptr.* = self._buf[buf_offset(kind) + offset ..].ptr;
}
}
}
}
}
// TODO: Rename
const Device = enum { nds9, nds7 };
pub fn read(self: @This(), comptime T: type, comptime dev: Device, address: u32) T {
const bits = @typeInfo(IntFittingRange(0, page_size - 1)).Int.bits;
const masked_addr = address & (addr_space_size - 1);
const page = masked_addr >> bits;
const offset = masked_addr & (page_size - 1);
const table = if (dev == .nds9) self.nds9_table else self.nds7_table;
if (table[page]) |some_ptr| {
const ptr: [*]const T = @ptrCast(@alignCast(some_ptr));
return ptr[offset / @sizeOf(T)];
}
log.err("{s}: read(T: {}, addr: 0x{X:0>8}) was in un-mapped VRAM space", .{ @tagName(dev), T, address });
return 0x00;
}
pub fn write(self: *@This(), comptime T: type, comptime dev: Device, address: u32, value: T) void {
const bits = @typeInfo(IntFittingRange(0, page_size - 1)).Int.bits;
const masked_addr = address & (addr_space_size - 1);
const page = masked_addr >> bits;
const offset = masked_addr & (page_size - 1);
const table = if (dev == .nds9) self.nds9_table else self.nds7_table;
if (table[page]) |some_ptr| {
const ptr: [*]T = @ptrCast(@alignCast(some_ptr));
ptr[offset / @sizeOf(T)] = value;
return;
}
log.err("{s}: write(T: {}, addr: 0x{X:0>8}, value: 0x{X:0>8}) was in un-mapped VRA< space", .{ @tagName(dev), T, address, value });
}
};

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const std = @import("std");
const KiB = 0x400;
const Allocator = std.mem.Allocator;
const IntFittingRange = std.math.IntFittingRange;
const page_size = 16 * KiB; // smallest allocation is 16 KiB
const addr_space_size = 0x0100_0000; // 0x0600_0000 -> 0x06FF_FFFF (inclusive)
const table_len = addr_space_size / page_size;
const buf_len = 656 * KiB;
const log = std.log.scoped(.vram);
io: Io = .{},
_buf: *[buf_len]u8,
nds9_table: *const [table_len]?[*]u8,
nds7_table: *const [table_len]?[*]u8,
const Io = struct {
pub const Vramstat = nds7.Vramstat;
const nds9 = @import("../nds9/io.zig");
const nds7 = @import("../nds7/io.zig");
stat: nds7.Vramstat = .{ .raw = 0x00 },
/// Write-Only (according to melonDS these are readable lol)
cnt_a: nds9.Vramcnt.A = .{ .raw = 0x00 },
cnt_b: nds9.Vramcnt.A = .{ .raw = 0x00 },
cnt_c: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_d: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_e: nds9.Vramcnt.E = .{ .raw = 0x00 },
cnt_f: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_g: nds9.Vramcnt.C = .{ .raw = 0x00 },
cnt_h: nds9.Vramcnt.H = .{ .raw = 0x00 },
cnt_i: nds9.Vramcnt.H = .{ .raw = 0x00 },
};
pub fn init(self: *@This(), allocator: Allocator) !void {
const buf = try allocator.create([buf_len]u8);
errdefer allocator.destroy(buf);
@memset(buf, 0);
const tables = try allocator.alloc(?[*]u8, 2 * table_len);
@memset(tables, null);
self.* = .{
.nds9_table = tables[0..table_len],
.nds7_table = tables[table_len .. 2 * table_len],
._buf = buf,
};
// ROMS like redpanda.nds won't write to VRAMCNT before trying to write to VRAM
// therefore we assume some default allocation (in this casee VRAMCNT_A -> VRAMCNT_I are 0x00)
self.update();
}
pub fn deinit(self: @This(), allocator: Allocator) void {
allocator.destroy(self._buf);
const ptr: [*]?[*]const u8 = @ptrCast(@constCast(self.nds9_table));
allocator.free(ptr[0 .. 2 * table_len]);
}
/// NDS7 VRAMSTAT
pub fn stat(self: *const @This()) Io.Vramstat {
const vram_c: u8 = @intFromBool(self.io.cnt_c.enable.read() and self.io.cnt_c.mst.read() == 2);
const vram_d: u8 = @intFromBool(self.io.cnt_d.enable.read() and self.io.cnt_d.mst.read() == 2);
return .{ .raw = (vram_d << 1) | vram_c };
}
const Kind = enum {
a,
b,
c,
d,
e,
f,
g,
h,
i,
/// In Bytes
inline fn size(self: @This()) u32 {
return switch (self) {
.a => 128 * KiB,
.b => 128 * KiB,
.c => 128 * KiB,
.d => 128 * KiB,
.e => 64 * KiB,
.f => 16 * KiB,
.g => 16 * KiB,
.h => 32 * KiB,
.i => 16 * KiB,
};
}
};
// TODO: Rename
fn range(comptime kind: Kind, mst: u3, offset: u2) u32 {
const ofs: u32 = offset;
// panic messages are from GBATEK
return switch (kind) {
.a => switch (mst) {
0 => 0x0680_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0640_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_A: Slot OFS(0-3)"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.b => switch (mst) {
0 => 0x0682_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0640_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_B: Slot OFS(0-3)"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.c => switch (mst) {
0 => 0x0684_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0600_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_C: Slot OFS(0-3)"),
4 => 0x0620_0000,
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.d => switch (mst) {
0 => 0x0686_0000,
1 => 0x0600_0000 + (0x0002_0000 * ofs),
2 => 0x0600_0000 + (0x0002_0000 * (ofs & 0b01)),
3 => @panic("VRAMCNT_D: Slot OFS(0-3)"),
4 => 0x0660_0000,
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.e => switch (mst) {
0 => 0x0688_0000,
1 => 0x0600_0000,
2 => 0x0640_0000,
3 => @panic("VRAMCNT_E: Slots 0-3"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.f => switch (mst) {
0 => 0x0689_0000,
1 => 0x0600_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
2 => 0x0640_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
3 => @panic("VRAMCNT_F: Slot (OFS.0*1)+(OFS.1*4)"),
4 => @panic("VRAMCNT_F: Slot 0-1 (OFS=0), Slot 2-3 (OFS=1)"),
5 => @panic("VRAMCNT_F: Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.g => switch (mst) {
0 => 0x0689_4000,
1 => 0x0600_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
2 => 0x0640_0000 + (0x0000_4000 * (ofs & 0b01)) + (0x0001_0000 * (ofs >> 1)),
3 => @panic("VRAMCNT_G: Slot (OFS.0*1)+(OFS.1*4)"),
4 => @panic("VRAMCNT_G: Slot 0-1 (OFS=0), Slot 2-3 (OFS=1)"),
5 => @panic("VRAMCNT_G: Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.h => switch (mst) {
0 => 0x0689_8000,
1 => 0x0620_0000,
2 => @panic("VRAMCNT_H: Slot 0-3"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
.i => switch (mst) {
0 => 0x068A_0000,
1 => 0x0620_8000,
2 => 0x0660_0000,
3 => @panic("Slot 0"),
else => std.debug.panic("Invalid MST for VRAMCNT_{s}", .{[_]u8{std.ascii.toUpper(@tagName(kind)[0])}}),
},
};
}
fn buf_offset(comptime kind: Kind) usize {
// zig fmt: off
return switch (kind) {
.a => 0, // 0x00000
.b => (128 * KiB) * 1, // 0x20000 (+ 0x20000)
.c => (128 * KiB) * 2, // 0x40000 (+ 0x20000)
.d => (128 * KiB) * 3, // 0x60000 (+ 0x20000)
.e => (128 * KiB) * 4, // 0x80000 (+ 0x20000)
.f => (128 * KiB) * 4 + (64 * KiB), // 0x90000 (+ 0x10000)
.g => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 1, // 0x94000 (+ 0x04000)
.h => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 2, // 0x98000 (+ 0x04000)
.i => (128 * KiB) * 4 + (64 * KiB) + (16 * KiB) * 2 + (32 * KiB) // 0xA0000 (+ 0x08000)
};
// zig fmt: on
}
fn CntType(comptime kind: Kind) type {
const Vramcnt = @import("../nds9/io.zig").Vramcnt;
return switch (kind) {
.a => Vramcnt.A,
.b => Vramcnt.A,
.c => Vramcnt.C,
.d => Vramcnt.C,
.e => Vramcnt.E,
.f => Vramcnt.C,
.g => Vramcnt.C,
.h => Vramcnt.H,
.i => Vramcnt.H,
};
}
fn cntValue(self: *const @This(), comptime kind: Kind) CntType(kind) {
return switch (kind) {
.a => self.io.cnt_a,
.b => self.io.cnt_b,
.c => self.io.cnt_c,
.d => self.io.cnt_d,
.e => self.io.cnt_e,
.f => self.io.cnt_f,
.g => self.io.cnt_g,
.h => self.io.cnt_h,
.i => self.io.cnt_i,
};
}
// TODO: We always update the entirety of VRAM when that argubably isn't necessary
pub fn update(self: *@This()) void {
const nds9_tbl = @constCast(self.nds9_table);
const nds7_tbl = @constCast(self.nds7_table);
for (nds9_tbl, nds7_tbl, 0..) |*nds9_ptr, *nds7_ptr, i| {
const addr = 0x0600_0000 + (i * page_size);
inline for (std.meta.fields(Kind)) |f| {
const kind = @field(Kind, f.name);
const cnt = cntValue(self, kind);
const ofs = switch (kind) {
.e, .h, .i => 0,
else => cnt.offset.read(),
};
const min = range(kind, cnt.mst.read(), ofs);
const max = min + kind.size();
const offset = addr & (kind.size() - 1);
if (min <= addr and addr < max) {
if ((kind == .c or kind == .d) and cnt.mst.read() == 2) {
// Allocate to ARM7
nds7_ptr.* = self._buf[buf_offset(kind) + offset ..].ptr;
} else {
nds9_ptr.* = self._buf[buf_offset(kind) + offset ..].ptr;
}
}
}
}
}
// TODO: Rename
const Device = enum { nds9, nds7 };
pub fn read(self: @This(), comptime T: type, comptime dev: Device, address: u32) T {
const bits = @typeInfo(IntFittingRange(0, page_size - 1)).Int.bits;
const masked_addr = address & (addr_space_size - 1);
const page = masked_addr >> bits;
const offset = masked_addr & (page_size - 1);
const table = if (dev == .nds9) self.nds9_table else self.nds7_table;
if (table[page]) |some_ptr| {
const ptr: [*]const T = @ptrCast(@alignCast(some_ptr));
return ptr[offset / @sizeOf(T)];
}
log.err("{s}: read(T: {}, addr: 0x{X:0>8}) was in un-mapped VRAM space", .{ @tagName(dev), T, address });
return 0x00;
}
pub fn write(self: *@This(), comptime T: type, comptime dev: Device, address: u32, value: T) void {
const bits = @typeInfo(IntFittingRange(0, page_size - 1)).Int.bits;
const masked_addr = address & (addr_space_size - 1);
const page = masked_addr >> bits;
const offset = masked_addr & (page_size - 1);
const table = if (dev == .nds9) self.nds9_table else self.nds7_table;
if (table[page]) |some_ptr| {
const ptr: [*]T = @ptrCast(@alignCast(some_ptr));
ptr[offset / @sizeOf(T)] = value;
return;
}
log.err("{s}: write(T: {}, addr: 0x{X:0>8}, value: 0x{X:0>8}) was in un-mapped VRA< space", .{ @tagName(dev), T, address, value });
}

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const std = @import("std");
const Bus = @import("../nds9/Bus.zig");
const FrameBuffer = @import("../ppu.zig").FrameBuffer;
const DispcntA = @import("../nds9/io.zig").DispcntA;
const DispcntB = @import("../nds9/io.zig").DispcntB;
const Dispstat = @import("../nds9/io.zig").Dispstat;
const Vcount = @import("../nds9/io.zig").Vcount;
const PowCnt = @import("../nds9/io.zig").PowCnt;
const width = @import("../ppu.zig").screen_width;
const height = @import("../ppu.zig").screen_height;
const EngineKind = enum { a, b };
pub const EngineA = Engine(.a);
pub const EngineB = Engine(.b);
fn Engine(comptime kind: EngineKind) type {
const log = std.log.scoped(.engine2d);
_ = log; // TODO: specify between 2D-A and 2D-B
// FIXME: don't commit zig crimes
const Type = struct {
fn inner(comptime TypeA: type, comptime TypeB: type) type {
return if (kind == .a) TypeA else TypeB;
}
}.inner;
return struct {
dispcnt: Type(DispcntA, DispcntB) = .{ .raw = 0x0000_0000 },
dispstat: Dispstat = .{ .raw = 0x0000_0000 },
vcount: Vcount = .{ .raw = 0x0000_0000 },
pub fn drawScanline(self: *@This(), bus: *Bus, fb: *FrameBuffer, powcnt: *PowCnt) void {
const disp_mode = self.dispcnt.display_mode.read();
switch (disp_mode) {
0 => { // Display Off
const buf = switch (kind) {
.a => if (powcnt.display_swap.read()) fb.top(.back) else fb.btm(.back),
.b => if (powcnt.display_swap.read()) fb.btm(.back) else fb.top(.back),
};
@memset(buf, 0xFF); // set everything to white
},
1 => @panic("TODO: standard graphics display (text mode, etc)"),
2 => { // VRAM display
if (kind == .b) return;
// TODO: Master Brightness can still affect this mode
const scanline: u32 = self.vcount.scanline.read();
const buf = if (powcnt.display_swap.read()) fb.top(.back) else fb.btm(.back);
const scanline_buf = blk: {
const rgba_ptr: *[width * height]u32 = @ptrCast(@alignCast(buf));
break :blk rgba_ptr[width * scanline ..][0..width];
};
const base_addr: u32 = 0x0680_0000 + (width * @sizeOf(u16)) * @as(u32, scanline);
for (scanline_buf, 0..) |*rgba, i| {
const addr = base_addr + @as(u32, @intCast(i)) * @sizeOf(u16);
rgba.* = rgba888(bus.dbgRead(u16, addr));
}
},
3 => {
if (kind == .b) return;
@panic("TODO: main memory display");
},
}
}
};
}
inline fn rgba888(bgr555: u16) u32 {
const b: u32 = bgr555 >> 10 & 0x1F;
const g: u32 = bgr555 >> 5 & 0x1F;
const r: u32 = bgr555 & 0x1F;
// zig fmt: off
return (r << 3 | r >> 2) << 24
| (g << 3 | g >> 2) << 16
| (b << 3 | b >> 2) << 8
| 0xFF;
// zig fmt: on
}