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chore: improve APU accuracy + scheduler refactoring

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This commit is contained in:
Rekai Nyangadzayi Musuka
2022-05-20 16:01:12 -03:00
parent e7777737b3
commit af2ad6c924
5 changed files with 39 additions and 43 deletions
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66
src/apu.zig
View File

@@ -60,12 +60,12 @@ pub const Apu = struct {
.fs = FrameSequencer.init(),
};
sched.push(.SampleAudio, sched.now() + apu.sampleTicks());
sched.push(.{ .ApuChannel = 0 }, sched.now() + SquareWave.ticks); // Channel 1
sched.push(.{ .ApuChannel = 1 }, sched.now() + SquareWave.ticks); // Channel 2
sched.push(.{ .ApuChannel = 2 }, sched.now() + WaveDevice.ticks); // Channel 3
sched.push(.{ .ApuChannel = 3 }, sched.now() + Noise.ticks); // Channel 4
sched.push(.FrameSequencer, sched.now() + ((1 << 24) / 512));
sched.push(.SampleAudio, apu.sampleTicks());
sched.push(.{ .ApuChannel = 0 }, SquareWave.tickInterval); // Channel 1
sched.push(.{ .ApuChannel = 1 }, SquareWave.tickInterval); // Channel 2
sched.push(.{ .ApuChannel = 2 }, WaveDevice.tickInterval); // Channel 3
sched.push(.{ .ApuChannel = 3 }, Lfsr.tickInterval); // Channel 4
sched.push(.FrameSequencer, ((1 << 24) / 512));
return apu;
}
@@ -143,6 +143,11 @@ pub const Apu = struct {
const ch_left: u4 = self.psg_cnt.ch_left.read();
const ch_right: u4 = self.psg_cnt.ch_right.read();
// FIXME: Obscure behaviour?
// Apply NR50 Volume Modifications
const left_master_vol = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) / 7.0;
const right_master_vol = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) / 7.0;
// Apply SOUNDCNT_H Volume Modifications
const gba_vol: f32 = switch (self.dma_cnt.ch_vol.read()) {
0b00 => 0.25,
@@ -152,35 +157,27 @@ pub const Apu = struct {
};
// Sample Channel 1
const ch1_sample = self.highPass(self.ch1.amplitude(), any_ch_enabled) * gba_vol;
const ch1_sample = self.highPass(self.ch1.amplitude(), any_ch_enabled);
const ch1_left = if (ch_left & 1 == 1) ch1_sample else 0;
const ch1_right = if (ch_right & 1 == 1) ch1_sample else 0;
// Sample Channel 2
const ch2_sample = self.highPass(self.ch2.amplitude(), any_ch_enabled) * gba_vol;
const ch2_sample = self.highPass(self.ch2.amplitude(), any_ch_enabled);
const ch2_left = if (ch_left >> 1 & 1 == 1) ch2_sample else 0;
const ch2_right = if (ch_right >> 1 & 1 == 1) ch2_sample else 0;
// Sample Channel 3
const ch3_sample = self.highPass(self.ch3.amplitude(), any_ch_enabled) * gba_vol;
const ch3_sample = self.highPass(self.ch3.amplitude(), any_ch_enabled);
const ch3_left = if (ch_left >> 2 & 1 == 1) ch3_sample else 0;
const ch3_right = if (ch_right >> 2 & 1 == 1) ch3_sample else 0;
// Sample Channel 4
const ch4_sample = self.highPass(self.ch4.amplitude(), any_ch_enabled) * gba_vol;
const ch4_sample = self.highPass(self.ch4.amplitude(), any_ch_enabled);
const ch4_left = if (ch_left >> 3 == 1) ch4_sample else 0;
const ch4_right = if (ch_right >> 3 == 1) ch4_sample else 0;
const mixed_left = ch1_left + ch2_left + ch3_left + ch4_left / 4;
const mixed_right = ch1_right + ch2_right + ch3_right + ch4_right / 4;
// FIXME: Obscure behaviour?
// Apply NR50 Volume Modifications
const left_master_vol = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) / 7;
const right_master_vol = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) / 7;
const psg_left = mixed_left * left_master_vol;
const psg_right = mixed_right * right_master_vol;
const psg_left = (ch1_left + ch2_left + ch3_left + ch4_left) * left_master_vol * gba_vol;
const psg_right = (ch1_right + ch2_right + ch3_right + ch4_right) * right_master_vol * gba_vol;
// Sample Dma Channels
const chA_sample = if (self.dma_cnt.chA_vol.read()) self.chA.amplitude() * 4 else self.chA.amplitude() * 2;
@@ -192,8 +189,8 @@ pub const Apu = struct {
const chB_right = if (self.dma_cnt.chB_right.read()) chB_sample else 0;
// Mix all Channels
const left = (chA_left + chB_left + psg_left) / 3;
const right = (chA_right + chB_right + psg_right) / 3;
const left = (chA_left + chB_left + psg_left) / 6.0;
const right = (chA_right + chB_right + psg_right) / 6.0;
if (self.sampling_cycle != self.bias.sampling_cycle.read()) {
log.info("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() });
@@ -210,7 +207,7 @@ pub const Apu = struct {
while (SDL.SDL_AudioStreamAvailable(self.stream) > (@sizeOf(f32) * 2 * 0x800)) {}
_ = SDL.SDL_AudioStreamPut(self.stream, &[2]f32{ left, right }, 2 * @sizeOf(f32));
self.sched.push(.SampleAudio, self.sched.now() + self.sampleTicks() - late);
self.sched.push(.SampleAudio, self.sampleTicks() -| late);
}
fn sampleTicks(self: *const Self) u64 {
@@ -235,7 +232,7 @@ pub const Apu = struct {
1, 3, 5 => {},
}
self.sched.push(.FrameSequencer, self.sched.now() + ((1 << 24) / 512) - late);
self.sched.push(.FrameSequencer, ((1 << 24) / 512) -| late);
}
fn tickLengths(self: *Self) void {
@@ -709,7 +706,6 @@ const Wave = struct {
const Noise = struct {
const Self = @This();
const ticks = (1 << 24) / (1 << 22);
/// Write-only
/// NR41
@@ -854,7 +850,7 @@ pub fn DmaSound(comptime kind: DmaSoundKind) type {
}
pub fn push(self: *Self, value: u32) void {
self.fifo.write(&intToBytes(u32, value)) catch {};
self.fifo.write(&intToBytes(u32, value)) catch |e| log.err("{} Error: {}", .{ kind, e });
}
pub fn len(self: *const Self) usize {
@@ -951,7 +947,7 @@ const EnvelopeDevice = struct {
const WaveDevice = struct {
const Self = @This();
const wave_len = 0x20;
const ticks = (1 << 24) / (1 << 22);
const tickInterval: u64 = (1 << 24) / (1 << 22);
buf: [wave_len]u8,
timer: u16,
@@ -973,7 +969,7 @@ const WaveDevice = struct {
const timer = (2048 - @as(u64, value)) * 4;
self.timer = @truncate(u11, timer);
self.sched.push(.{ .ApuChannel = 2 }, self.sched.now() + timer * ticks);
self.sched.push(.{ .ApuChannel = 2 }, timer * tickInterval);
}
fn handleTimerOverflow(self: *Self, cnt_freq: io.Frequency, cnt_sel: io.WaveSelect, late: u64) void {
@@ -987,7 +983,7 @@ const WaveDevice = struct {
self.offset = (self.offset + 1) % 0x20; // 0x10 bytes, which contain 2 samples each
}
self.sched.push(.{ .ApuChannel = 2 }, self.sched.now() + timer * ticks - late);
self.sched.push(.{ .ApuChannel = 2 }, timer * tickInterval -| late);
}
fn sample(self: *const Self, cnt: io.WaveSelect) u4 {
@@ -1046,7 +1042,7 @@ const WaveDevice = struct {
const SquareWave = struct {
const Self = @This();
const ticks: u64 = (1 << 24) / (1 << 22);
const tickInterval: u64 = (1 << 24) / (1 << 22);
pos: u3,
sched: *Scheduler,
@@ -1098,7 +1094,7 @@ const SquareWave = struct {
self.timer = @truncate(u12, timer);
self.pos +%= 1;
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, self.sched.now() + timer * ticks - late);
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, timer * tickInterval -| late);
}
fn reloadTimer(self: *Self, comptime kind: ChannelKind, value: u11) void {
@@ -1108,7 +1104,7 @@ const SquareWave = struct {
const timer = (tmp & ~@as(u64, 0x3)) | self.timer & 0x3; // Keep the last two bits from the old timer
self.timer = @truncate(u12, timer);
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, self.sched.now() + timer * ticks);
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, timer * tickInterval);
}
fn sample(self: *const Self, cnt: io.Duty) u1 {
@@ -1129,7 +1125,7 @@ const SquareWave = struct {
// Linear Feedback Shift Register
const Lfsr = struct {
const Self = @This();
const ticks = (1 << 24) / (1 << 22);
const tickInterval: u64 = (1 << 24) / (1 << 22);
shift: u15,
timer: u16,
@@ -1169,7 +1165,7 @@ const Lfsr = struct {
const div = Self.divisor(poly.div_ratio.read());
const timer = @as(u64, div << poly.shift.read());
self.sched.push(.{ .ApuChannel = 3 }, self.sched.now() + timer * ticks);
self.sched.push(.{ .ApuChannel = 3 }, timer * tickInterval);
}
fn handleTimerOverflow(self: *Self, poly: io.PolyCounter, late: u64) void {
@@ -1182,7 +1178,7 @@ const Lfsr = struct {
if (poly.width.read())
self.shift = (self.shift & ~@as(u15, 0x40)) | tmp << 6;
self.sched.push(.{ .ApuChannel = 3 }, self.sched.now() + timer * ticks - late);
self.sched.push(.{ .ApuChannel = 3 }, timer * tickInterval -| late);
}
fn divisor(code: u3) u16 {

2
src/bus/timer.zig
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@@ -126,7 +126,7 @@ fn Timer(comptime id: u2) type {
const when = (@as(u64, 0x10000) - self._counter) * self.frequency();
self._start_timestamp = self.sched.now();
self.sched.push(.{ .TimerOverflow = id }, self.sched.now() + when - late);
self.sched.push(.{ .TimerOverflow = id }, when -| late);
}
fn frequency(self: *const Self) u16 {

2
src/cpu.zig
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@@ -269,8 +269,8 @@ pub const Arm7tdmi = struct {
pub fn handleDMATransfers(self: *Self) void {
while (self.bus.isDmaRunning()) {
if (self.bus.dma[1].step(self)) continue;
if (self.bus.dma[0].step(self)) continue;
if (self.bus.dma[1].step(self)) continue;
if (self.bus.dma[2].step(self)) continue;
if (self.bus.dma[3].step(self)) continue;
}

8
src/ppu.zig
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@@ -44,7 +44,7 @@ pub const Ppu = struct {
pub fn init(alloc: Allocator, sched: *Scheduler) !Self {
// Queue first Hblank
sched.push(.Draw, sched.tick + (240 * 4));
sched.push(.Draw, 240 * 4);
const framebufs = try alloc.alloc(u8, (framebuf_pitch * height) * 2);
std.mem.set(u8, framebufs, 0);
@@ -429,7 +429,7 @@ pub const Ppu = struct {
pollBlankingDma(&cpu.bus, .HBlank);
self.dispstat.hblank.set();
self.sched.push(.HBlank, self.sched.now() + (68 * 4) - late);
self.sched.push(.HBlank, 68 * 4 -| late);
}
pub fn handleHBlankEnd(self: *Self, cpu: *Arm7tdmi, late: u64) void {
@@ -451,7 +451,7 @@ pub const Ppu = struct {
if (scanline < 160) {
// Transitioning to another Draw
self.sched.push(.Draw, self.sched.now() + (240 * 4) - late);
self.sched.push(.Draw, 240 * 4 -| late);
} else {
// Transitioning to a Vblank
if (scanline == 160) {
@@ -469,7 +469,7 @@ pub const Ppu = struct {
}
if (scanline == 227) self.dispstat.vblank.unset();
self.sched.push(.VBlank, self.sched.now() + (240 * 4) - late);
self.sched.push(.VBlank, 240 * 4 -| late);
}
}
};

4
src/scheduler.zig
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@@ -16,7 +16,7 @@ pub const Scheduler = struct {
pub fn init(alloc: Allocator) Self {
var sched = Self{ .tick = 0, .queue = PriorityQueue(Event, void, lessThan).init(alloc, {}) };
sched.push(.HeatDeath, std.math.maxInt(u64));
sched.queue.add(.{ .kind = .HeatDeath, .tick = std.math.maxInt(u64) }) catch unreachable;
return sched;
}
@@ -87,7 +87,7 @@ pub const Scheduler = struct {
}
pub fn push(self: *Self, kind: EventKind, end: u64) void {
self.queue.add(.{ .kind = kind, .tick = end }) catch unreachable;
self.queue.add(.{ .kind = kind, .tick = self.now() + end }) catch unreachable;
}
pub fn nextTimestamp(self: *Self) u64 {