From af8fe66c430e31394562c5baa45d0b457524bc01 Mon Sep 17 00:00:00 2001 From: Rekai Musuka Date: Fri, 21 Oct 2022 05:12:36 -0300 Subject: [PATCH] feat: implement ch1 TODO: It's really loud --- src/apu.zig | 181 ++++++++++++++++++++++++++++++++++++------------- src/bus/io.zig | 15 ++-- 2 files changed, 143 insertions(+), 53 deletions(-) diff --git a/src/apu.zig b/src/apu.zig index 7bc8d4b..0eb8a1b 100644 --- a/src/apu.zig +++ b/src/apu.zig @@ -24,7 +24,8 @@ pub const Apu = struct { chB: DmaSound(.B), bias: io.SoundBias, - ch_vol_cnt: io.ChannelVolumeControl, + /// NR51 + psg_cnt: io.ChannelVolumeControl, dma_cnt: io.DmaSoundControl, cnt: io.SoundControl, @@ -33,6 +34,7 @@ pub const Apu = struct { sched: *Scheduler, fs: FrameSequencer, + capacitor: f32, pub fn init(sched: *Scheduler) Self { const apu: Self = .{ @@ -43,7 +45,7 @@ pub const Apu = struct { .chA = DmaSound(.A).init(), .chB = DmaSound(.B).init(), - .ch_vol_cnt = .{ .raw = 0 }, + .psg_cnt = .{ .raw = 0 }, .dma_cnt = .{ .raw = 0 }, .cnt = .{ .raw = 0 }, .bias = .{ .raw = 0x0200 }, @@ -52,16 +54,22 @@ pub const Apu = struct { .stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, 1 << 15, SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable, .sched = sched, + .capacitor = 0, .fs = FrameSequencer.init(), }; sched.push(.SampleAudio, sched.now() + apu.sampleTicks()); sched.push(.{ .ApuChannel = 0 }, sched.now() + SquareWave.ticks); - sched.push(.FrameSequencer, sched.now() + ((1 << 24) / 1 << 15)); + sched.push(.FrameSequencer, sched.now() + ((1 << 24) / 512)); return apu; } + fn reset(self: *Self) void { + self.ch1.reset(); + // TODO: Reset the rest of the channels + } + pub fn setDmaCnt(self: *Self, value: u16) void { const new: io.DmaSoundControl = .{ .raw = value }; @@ -80,11 +88,12 @@ pub const Apu = struct { if (value) { self.fs.step = 0; // Reset Frame Sequencer - // TODO: Reset Duty position for Square channels + // TODO: Reset Duty Position for Ch2 Square + self.ch1.square.pos = 0; // TODO: Reset Channel 3 offset ptr } else { - // TODO: Reset APU + self.reset(); } } @@ -102,12 +111,12 @@ pub const Apu = struct { /// NR50 pub fn setSoundCntLLow(self: *Self, byte: u8) void { - self.ch_vol_cnt.raw = (self.ch_vol_cnt.raw & 0xFF00) | byte; + self.psg_cnt.raw = (self.psg_cnt.raw & 0xFF00) | byte; } /// NR51 pub fn setSoundCntLHigh(self: *Self, byte: u8) void { - self.ch_vol_cnt.raw = @as(u16, byte) << 8 | (self.ch_vol_cnt.raw & 0xFF); + self.psg_cnt.raw = @as(u16, byte) << 8 | (self.psg_cnt.raw & 0xFF); } pub fn setBiasHigh(self: *Self, byte: u8) void { @@ -117,9 +126,31 @@ pub const Apu = struct { pub fn sampleAudio(self: *Self, late: u64) void { // Sample Channel 1 - const ch1_sample = self.ch1.amplitude(); - const ch1_left = if (self.ch_vol_cnt.ch1_left.read()) ch1_sample else 0; - const ch1_right = if (self.ch_vol_cnt.ch1_right.read()) ch1_sample else 0; + const ch1_sample = self.highPassFilter(self.ch1.amplitude(), self.ch1.enabled); + const ch1_left = if (self.psg_cnt.ch1_left.read()) ch1_sample else 0; + const ch1_right = if (self.psg_cnt.ch1_right.read()) ch1_sample else 0; + + const mixed_left = ch1_left; + const mixed_right = ch1_right; + + // Apply NR50 Volume Modifications + const nr50_left = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) * mixed_left; + const nr50_right = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) * mixed_right; + + // Apply SOUNDCNT_H Volume Modifications + const psg_left = switch (self.dma_cnt.ch_vol.read()) { + 0b00 => nr50_left * 0.25, + 0b01 => nr50_left * 0.5, + 0b10 => nr50_left * 0.75, + 0b11 => nr50_left, // Prohibited + }; + + const psg_right = switch (self.dma_cnt.ch_vol.read()) { + 0b00 => nr50_right * 0.25, + 0b01 => nr50_right * 0.5, + 0b10 => nr50_right * 0.75, + 0b11 => nr50_right, // Prohibited + }; // Sample Dma Channels // const chA = if (self.dma_cnt.chA_vol.read()) self.chA.amplitude() else self.chA.amplitude() / 2; @@ -131,10 +162,10 @@ pub const Apu = struct { // const chB_right = if (self.dma_cnt.chB_right.read()) chB else 0; // Mix all Channels - // const left = (chA_left + chB_left + ch1_left) / 3; - // const right = (chA_right + chB_right + ch1_right) / 3 - const left = ch1_left; - const right = ch1_right; + // const left = (chA_left + chB_left + psg_left) / 3; + // const right = (chA_right + chB_right + psg_right) / 3 + const left = psg_left; + const right = psg_right; if (self.sampling_cycle != self.bias.sampling_cycle.read()) { log.warn("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() }); @@ -176,7 +207,7 @@ pub const Apu = struct { 1, 3, 5 => {}, } - self.sched.push(.FrameSequencer, self.sched.now() + ((1 << 24) / 1 << 15) - late); + self.sched.push(.FrameSequencer, self.sched.now() + ((1 << 24) / 512) - late); } fn tickLengths(self: *Self) void { @@ -205,6 +236,18 @@ pub const Apu = struct { if (self.chB.len() <= 15) cpu.bus.dma._2.enableSoundDma(0x0400_00A4); } } + + fn highPassFilter(self: *Self, sample: f32, ch_enabled: bool) f32 { + const charge_factor = 0.999958; + + var output: f32 = 0; + if (ch_enabled) { + output = sample - self.capacitor; + self.capacitor = sample - output * std.math.pow(f32, charge_factor, @intToFloat(f32, (1 << 22) / self.sampleRate())); + } + + return output; + } }; const ToneSweep = struct { @@ -221,15 +264,12 @@ const ToneSweep = struct { /// Length Functionality len_dev: Length, - /// Sweep Functionality sweep_dev: Sweep, - /// Envelope Functionality env_dev: Envelope, - + /// Frequency Timer Functionality square: SquareWave, - enabled: bool, sample: u8, @@ -257,11 +297,11 @@ const ToneSweep = struct { this.timer = if (period == 0) 8 else period; if (this.enabled and period != 0) { - const new_freq: u11 = this.calcFrequency(ch1); + const new_freq = this.calcFrequency(ch1); if (new_freq <= 0x7FF and ch1.sweep.shift.read() != 0) { - ch1.freq.frequency.write(new_freq); - this.shadow = new_freq; + ch1.freq.frequency.write(@truncate(u11, new_freq)); + this.shadow = @truncate(u11, new_freq); _ = this.calcFrequency(ch1); } @@ -269,10 +309,12 @@ const ToneSweep = struct { } } - fn calcFrequency(this: *This, ch1: *Self) u11 { - const shadow_shifted = this.shadow >> ch1.sweep.shift.read(); + fn calcFrequency(this: *This, ch1: *Self) u12 { + const shadow = @as(u12, this.shadow); + const shadow_shifted = shadow >> ch1.sweep.shift.read(); const decrease = ch1.sweep.direction.read(); - const freq = if (decrease) this.shadow - shadow_shifted else this.shadow + shadow_shifted; + + const freq = if (decrease) shadow - shadow_shifted else shadow + shadow_shifted; if (freq > 0x7FF) ch1.enabled = false; @@ -296,6 +338,16 @@ const ToneSweep = struct { }; } + fn reset(self: *Self) void { + self.sweep.raw = 0; + self.duty.raw = 0; + self.envelope.raw = 0; + self.freq.raw = 0; + + self.sample = 0; + self.enabled = false; + } + fn tickSweep(self: *Self) void { self.sweep_dev.tick(self); } @@ -313,17 +365,23 @@ const ToneSweep = struct { self.sample = 0; if (!self.isDacEnabled()) return; - self.sample = if (self.enabled) self.square.getSample(self.duty) * self.env_dev.vol else 0; + self.sample = if (self.enabled) self.square.sample(self.duty) * self.env_dev.vol else 0; } fn amplitude(self: *const Self) f32 { return (@intToFloat(f32, self.sample) / 7.5) - 1.0; } + /// NR11, NR12 + pub fn setSoundCntH(self: *Self, value: u16) void { + self.setDuty(@truncate(u8, value)); + self.setEnvelope(@truncate(u8, value >> 8)); + } + /// NR11 pub fn setDuty(self: *Self, value: u8) void { self.duty.raw = value; - self.len_dev.timer = 64 - self.duty.length.read(); + self.len_dev.timer = @as(u7, self.duty.length.read() ^ 0x3F); } /// NR12 @@ -332,25 +390,35 @@ const ToneSweep = struct { if (!self.isDacEnabled()) self.enabled = false; } + /// NR13, NR14 + pub fn setFreq(self: *Self, fs: *const FrameSequencer, value: u16) void { + self.setFreqLow(@truncate(u8, value)); + self.setFreqHigh(fs, @truncate(u8, value >> 8)); + } + /// NR13 pub fn setFreqLow(self: *Self, byte: u8) void { self.freq.raw = (self.freq.raw & 0xFF00) | byte; } /// NR14 - pub fn setFreqHigh(self: *Self, byte: u8) void { + pub fn setFreqHigh(self: *Self, fs: *const FrameSequencer, byte: u8) void { var new: io.Frequency = .{ .raw = (@as(u16, byte) << 8) | (self.freq.raw & 0xFF) }; if (new.trigger.read()) { + self.enabled = true; // FIXME: is this necessary? + if (self.len_dev.timer == 0) { self.len_dev.timer = 64; - // FIXME: This conflicts with my GB emulator - new.length_enable.write(false); + // We unset this on the old frequency because of the obscure + // behaviour outside of this if statement's scope + self.freq.length_enable.write(false); } - // TODO: Reload Frequency Timer (last two bits unmodified) + // TODO: Reload Frequency Timer self.square.reloadTimer(self.freq.frequency.read()); + // Reload Envelope period and timer self.env_dev.timer = self.envelope.period.read(); self.env_dev.vol = self.envelope.init_vol.read(); @@ -367,6 +435,7 @@ const ToneSweep = struct { self.enabled = self.isDacEnabled(); } + self.square.updateLength(fs, self, new); self.freq = new; } @@ -559,12 +628,16 @@ const FrameSequencer = struct { pub fn tick(self: *Self) void { self.step +%= 1; } + + fn lengthIsNext(self: *const Self) bool { + return (self.step +% 1) & 1 == 0; // Steps, 0, 2, 4, and 6 clock length + } }; const Length = struct { const Self = @This(); - timer: u16, + timer: u7, pub fn init() Self { return .{ .timer = 0 }; @@ -613,9 +686,9 @@ const Envelope = struct { self.timer = cnt.period.read(); if (cnt.direction.read()) { - if (self.vol > 0x0) self.vol -= 1; - } else { if (self.vol < 0xF) self.vol += 1; + } else { + if (self.vol > 0x0) self.vol -= 1; } } } @@ -624,43 +697,57 @@ const Envelope = struct { const SquareWave = struct { const Self = @This(); - const ticks: u64 = (1 << 24) / (1 << 18); + const ticks: u64 = (1 << 24) / (1 << 22); pos: u3, sched: *Scheduler, + timer: u12, pub fn init(sched: *Scheduler) Self { return .{ + .timer = 0, .pos = 0, .sched = sched, }; } - fn handleTimerOverflow(self: *Self, cnt: io.Frequency, late: u64) void { - const when = (2048 - @as(u64, cnt.frequency.read())) * 4; + /// Obscure NRx4 Behaviour + fn updateLength(_: *Self, fs: *const FrameSequencer, ch1: *ToneSweep, new_cnt: io.Frequency) void { + if (!fs.lengthIsNext() and !ch1.freq.length_enable.read() and new_cnt.length_enable.read() and ch1.len_dev.timer != 0) { + ch1.len_dev.timer -= 1; + if (ch1.len_dev.timer == 0 and !new_cnt.trigger.read()) ch1.enabled = false; + } + } + + fn handleTimerOverflow(self: *Self, cnt: io.Frequency, late: u64) void { + const timer = (2048 - @as(u64, cnt.frequency.read())) * 4; + + self.timer = @truncate(u12, timer); self.pos = (self.pos +% 1) & 7; - self.sched.push(.{ .ApuChannel = 0 }, when * ticks - late); + + self.sched.push(.{ .ApuChannel = 0 }, self.sched.now() + timer * ticks - late); } fn reloadTimer(self: *Self, value: u11) void { self.sched.removeScheduledEvent(.{ .ApuChannel = 0 }); - // TODO: Implement Obscure Behaviour - const when = (2048 - @as(u64, value)) * 4; + const tmp: u64 = (2048 - @as(u64, value)) * 4; // What Freq Timer should be assuming no weird behaviour + 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 = 0 }, when * ticks); + self.sched.push(.{ .ApuChannel = 0 }, self.sched.now() + timer * ticks); } - fn getSample(self: *const Self, cnt: io.Duty) u1 { - const pattern = cnt.pattern.read(); // 2^18 + fn sample(self: *const Self, cnt: io.Duty) u1 { + const pattern = cnt.pattern.read(); const i = self.pos ^ 7; // index of 0 should get highest bit const result = switch (pattern) { - 0b00 => @as(u8, 0b00000001) >> i, // 1/8th - 0b01 => @as(u8, 0b10000001) >> i, // 1/4th - 0b10 => @as(u8, 0b10000111) >> i, // 1/2nd - 0b11 => @as(u8, 0b01111110) >> i, // 3/4th + 0b00 => @as(u8, 0b00000001) >> i, // 12.5% + 0b01 => @as(u8, 0b00000011) >> i, // 25% + 0b10 => @as(u8, 0b00001111) >> i, // 50% + 0b11 => @as(u8, 0b11111100) >> i, // 75% }; return @truncate(u1, result); diff --git a/src/bus/io.zig b/src/bus/io.zig index 31ff65f..c4f1a3f 100644 --- a/src/bus/io.zig +++ b/src/bus/io.zig @@ -118,7 +118,7 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) T { 0x0400_0073 => bus.apu.ch3.vol.raw, 0x0400_0079 => bus.apu.ch4.envelope.raw, 0x0400_007C => bus.apu.ch4.poly.raw, - 0x0400_0081 => @truncate(T, bus.apu.ch_vol_cnt.raw >> 8), + 0x0400_0081 => @truncate(T, bus.apu.psg_cnt.raw >> 8), 0x0400_0089 => @truncate(T, bus.apu.bias.raw >> 8), // Serial Communication 1 @@ -151,7 +151,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void { // Sound 0x0400_0080 => { - bus.apu.ch_vol_cnt.raw = @truncate(u16, value); + bus.apu.psg_cnt.raw = @truncate(u16, value); bus.apu.dma_cnt.raw = @truncate(u16, value >> 16); }, 0x0400_00A0 => bus.apu.chA.push(value), @@ -232,7 +232,10 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void { 0x0400_004E, 0x0400_0056 => {}, // Not used // Sound - 0x0400_0080 => bus.apu.ch_vol_cnt.raw = value, + 0x0400_0060 => bus.apu.ch1.sweep.raw = @truncate(u8, value), + 0x0400_0062 => bus.apu.ch1.setSoundCntH(value), + 0x0400_0064 => bus.apu.ch1.setFreq(&bus.apu.fs, value), + 0x0400_0080 => bus.apu.psg_cnt.raw = value, 0x0400_0082 => bus.apu.setDmaCnt(value), 0x0400_0084 => bus.apu.setSoundCntX(value >> 7 & 1 == 1), 0x0400_0088 => bus.apu.bias.raw = value, @@ -314,7 +317,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void { 0x0400_0062 => bus.apu.ch1.duty.raw = value, 0x0400_0063 => bus.apu.ch1.envelope.raw = value, 0x0400_0064 => bus.apu.ch1.setFreqLow(value), - 0x0400_0065 => bus.apu.ch1.setFreqHigh(value), + 0x0400_0065 => bus.apu.ch1.setFreqHigh(&bus.apu.fs, value), 0x0400_0068 => bus.apu.ch2.duty.raw = value, 0x0400_0069 => bus.apu.ch2.envelope.raw = value, 0x0400_006C => bus.apu.ch2.setFreqLow(value), @@ -578,8 +581,8 @@ pub const NoiseControl = extern union { /// Read / Write pub const ChannelVolumeControl = extern union { - left_vol: Bitfield(u16, 0, 3), - right_vol: Bitfield(u16, 4, 3), + right_vol: Bitfield(u16, 0, 3), + left_vol: Bitfield(u16, 4, 3), ch1_right: Bit(u16, 8), ch2_right: Bit(u16, 9),