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paoda:april-fools
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paoda:apu-things
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216
src/apu.zig
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@ -53,7 +53,7 @@ pub const Apu = struct {
.bias = .{ .raw = 0x0200 }, .bias = .{ .raw = 0x0200 },
.sampling_cycle = 0b00, .sampling_cycle = 0b00,
.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_U16, 2, 1 << 15, SDL.AUDIO_U16, 2, host_sample_rate) orelse unreachable, .stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, 1 << 15, SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable,
.sched = sched, .sched = sched,
.capacitor = 0, .capacitor = 0,
@ -133,60 +133,64 @@ pub const Apu = struct {
} }
pub fn sampleAudio(self: *Self, late: u64) void { pub fn sampleAudio(self: *Self, late: u64) void {
var left: i16 = 0; // zig fmt: off
var right: i16 = 0; const any_ch_enabled = self.ch1.enabled
or self.ch2.enabled
or self.ch3.enabled
or self.ch4.enabled;
// zig fmt: on
// SOUNDCNT_L Channel Enable flags
const ch_left: u4 = self.psg_cnt.ch_left.read(); const ch_left: u4 = self.psg_cnt.ch_left.read();
const ch_right: u4 = self.psg_cnt.ch_right.read(); const ch_right: u4 = self.psg_cnt.ch_right.read();
// Determine SOUNDCNT_H volume modifications // FIXME: Obscure behaviour?
const gba_vol: u4 = switch (self.dma_cnt.ch_vol.read()) { // Apply NR50 Volume Modifications
0b00 => 2, const left_master_vol = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) / 7.0;
0b01 => 1, const right_master_vol = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) / 7.0;
else => 0,
// Apply SOUNDCNT_H Volume Modifications
const gba_vol: f32 = switch (self.dma_cnt.ch_vol.read()) {
0b00 => 0.25,
0b01 => 0.5,
0b10 => 0.75,
0b11 => 0.0,
}; };
// Add all PSG channels together // Sample Channel 1
left += if (ch_left & 1 == 1) self.ch1.amplitude() else 0; const ch1_sample = self.highPass(self.ch1.amplitude(), any_ch_enabled);
left += if (ch_left >> 1 & 1 == 1) self.ch2.amplitude() else 0; const ch1_left = if (ch_left & 1 == 1) ch1_sample else 0;
left += if (ch_left >> 2 & 1 == 1) self.ch3.amplitude() else 0; const ch1_right = if (ch_right & 1 == 1) ch1_sample else 0;
left += if (ch_left >> 3 == 1) self.ch4.amplitude() else 0;
right += if (ch_right & 1 == 1) self.ch1.amplitude() else 0; // Sample Channel 2
right += if (ch_right >> 1 & 1 == 1) self.ch2.amplitude() else 0; const ch2_sample = self.highPass(self.ch2.amplitude(), any_ch_enabled);
right += if (ch_right >> 2 & 1 == 1) self.ch3.amplitude() else 0; const ch2_left = if (ch_left >> 1 & 1 == 1) ch2_sample else 0;
right += if (ch_right >> 3 == 1) self.ch4.amplitude() else 0; const ch2_right = if (ch_right >> 1 & 1 == 1) ch2_sample else 0;
// Multiply by master channel volume // Sample Channel 3
left *= 1 + @as(i16, self.psg_cnt.left_vol.read()); const ch3_sample = self.highPass(self.ch3.amplitude(), any_ch_enabled);
right *= 1 + @as(i16, self.psg_cnt.right_vol.read()); 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;
// Apply GBA volume modifications to PSG Channels // Sample Channel 4
left >>= gba_vol; const ch4_sample = self.highPass(self.ch4.amplitude(), any_ch_enabled);
right >>= gba_vol; 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 chA_sample = self.chA.amplitude() << if (self.dma_cnt.chA_vol.read()) @as(u4, 2) else 1; const psg_left = (ch1_left + ch2_left + ch3_left + ch4_left) * left_master_vol * gba_vol;
const chB_sample = self.chB.amplitude() << if (self.dma_cnt.chB_vol.read()) @as(u4, 2) else 1; const psg_right = (ch1_right + ch2_right + ch3_right + ch4_right) * right_master_vol * gba_vol;
left += if (self.dma_cnt.chA_left.read()) chA_sample else 0; // Sample Dma Channels
left += if (self.dma_cnt.chB_left.read()) chB_sample else 0; const chA_sample = if (self.dma_cnt.chA_vol.read()) self.chA.amplitude() * 4 else self.chA.amplitude() * 2;
const chA_left = if (self.dma_cnt.chA_left.read()) chA_sample else 0;
const chA_right = if (self.dma_cnt.chA_right.read()) chA_sample else 0;
right += if (self.dma_cnt.chA_right.read()) chA_sample else 0; const chB_sample = if (self.dma_cnt.chB_vol.read()) self.chB.amplitude() * 4 else self.chB.amplitude() * 2;
right += if (self.dma_cnt.chB_right.read()) chB_sample else 0; const chB_left = if (self.dma_cnt.chB_left.read()) chB_sample else 0;
const chB_right = if (self.dma_cnt.chB_right.read()) chB_sample else 0;
// Add SOUNDBIAS // Mix all Channels
// FIXME: Is SOUNDBIAS 9-bit or 10-bit? const left = (chA_left + chB_left + psg_left) / 6.0;
const bias = @as(i16, self.bias.level.read()) << 1; const right = (chA_right + chB_right + psg_right) / 6.0;
left += bias;
right += bias;
const tmp_left = std.math.clamp(@intCast(u16, left), std.math.minInt(u11), std.math.maxInt(u11));
const tmp_right = std.math.clamp(@intCast(u16, left), std.math.minInt(u11), std.math.maxInt(u11));
// Extend to 16-bit signed audio samples
const final_left = (tmp_left << 5) | (tmp_left >> 6);
const final_right = (tmp_right << 5) | (tmp_right >> 6);
if (self.sampling_cycle != self.bias.sampling_cycle.read()) { if (self.sampling_cycle != self.bias.sampling_cycle.read()) {
log.info("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() }); log.info("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() });
@ -197,90 +201,15 @@ pub const Apu = struct {
defer SDL.SDL_FreeAudioStream(old); defer SDL.SDL_FreeAudioStream(old);
self.sampling_cycle = self.bias.sampling_cycle.read(); self.sampling_cycle = self.bias.sampling_cycle.read();
self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_U16, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_U16, 2, host_sample_rate) orelse unreachable; self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable;
} }
_ = SDL.SDL_AudioStreamPut(self.stream, &[2]u16{ final_left, final_right }, 2 * @sizeOf(u16)); 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.sampleTicks() -| late); self.sched.push(.SampleAudio, self.sampleTicks() -| late);
} }
// pub fn sampleAudio(self: *Self, late: u64) void {
// // zig fmt: off
// const any_ch_enabled = self.ch1.enabled
// or self.ch2.enabled
// or self.ch3.enabled
// or self.ch4.enabled;
// // zig fmt: on
// 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,
// 0b01 => 0.5,
// else => 1.0,
// };
// // Sample Channel 1
// 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);
// 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);
// 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);
// 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 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;
// const chA_left = if (self.dma_cnt.chA_left.read()) chA_sample else 0;
// const chA_right = if (self.dma_cnt.chA_right.read()) chA_sample else 0;
// const chB_sample = if (self.dma_cnt.chB_vol.read()) self.chB.amplitude() * 4 else self.chB.amplitude() * 2;
// const chB_left = if (self.dma_cnt.chB_left.read()) chB_sample else 0;
// 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) / 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() });
// // Sample Rate Changed, Create a new Resampler since i can't figure out how to change
// // the parameters of the old one
// const old = self.stream;
// defer SDL.SDL_FreeAudioStream(old);
// self.sampling_cycle = self.bias.sampling_cycle.read();
// self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable;
// }
// 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.sampleTicks() -| late);
// }
fn sampleTicks(self: *const Self) u64 { fn sampleTicks(self: *const Self) u64 {
return (1 << 24) / self.sampleRate(); return (1 << 24) / self.sampleRate();
} }
@ -367,7 +296,7 @@ const ToneSweep = struct {
square: SquareWave, square: SquareWave,
enabled: bool, enabled: bool,
sample: i8, sample: u8,
const SweepDevice = struct { const SweepDevice = struct {
const This = @This(); const This = @This();
@ -460,11 +389,11 @@ const ToneSweep = struct {
self.sample = 0; self.sample = 0;
if (!self.isDacEnabled()) return; if (!self.isDacEnabled()) return;
self.sample = if (self.enabled) self.square.sample(self.duty) * @as(i8, 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) i16 { fn amplitude(self: *const Self) f32 {
return @as(i16, self.sample); return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
} }
/// NR11, NR12 /// NR11, NR12
@ -555,7 +484,7 @@ const Tone = struct {
square: SquareWave, square: SquareWave,
enabled: bool, enabled: bool,
sample: i8, sample: u8,
fn init(sched: *Scheduler) Self { fn init(sched: *Scheduler) Self {
return .{ return .{
@ -594,11 +523,11 @@ const Tone = struct {
self.sample = 0; self.sample = 0;
if (!self.isDacEnabled()) return; if (!self.isDacEnabled()) return;
self.sample = if (self.enabled) self.square.sample(self.duty) * @as(i8, 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) i16 { fn amplitude(self: *const Self) f32 {
return @as(i16, self.sample); return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
} }
/// NR21, NR22 /// NR21, NR22
@ -680,7 +609,7 @@ const Wave = struct {
wave_dev: WaveDevice, wave_dev: WaveDevice,
enabled: bool, enabled: bool,
sample: i8, sample: u8,
fn init(sched: *Scheduler) Self { fn init(sched: *Scheduler) Self {
return .{ return .{
@ -767,12 +696,11 @@ const Wave = struct {
self.sample = 0; self.sample = 0;
if (!self.select.enabled.read()) return; if (!self.select.enabled.read()) return;
// Convert unsigned 4-bit wave sample to signed 8-bit sample self.sample = if (self.enabled) self.wave_dev.sample(self.select) >> self.wave_dev.shift(self.vol) else 0;
self.sample = (2 * @as(i8, self.wave_dev.sample(self.select)) - 15) >> self.wave_dev.shift(self.vol);
} }
fn amplitude(self: *const Self) i16 { fn amplitude(self: *const Self) f32 {
return @as(i16, self.sample); return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
} }
}; };
@ -799,7 +727,7 @@ const Noise = struct {
lfsr: Lfsr, lfsr: Lfsr,
enabled: bool, enabled: bool,
sample: i8, sample: u8,
fn init(sched: *Scheduler) Self { fn init(sched: *Scheduler) Self {
return .{ return .{
@ -893,11 +821,11 @@ const Noise = struct {
self.sample = 0; self.sample = 0;
if (!self.isDacEnabled()) return; if (!self.isDacEnabled()) return;
self.sample = if (self.enabled) self.lfsr.sample() * @as(i8, self.env_dev.vol) else 0; self.sample = if (self.enabled) self.lfsr.sample() * self.env_dev.vol else 0;
} }
fn amplitude(self: *const Self) i16 { fn amplitude(self: *const Self) f32 {
return @as(i16, self.sample); return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
} }
fn isDacEnabled(self: *const Self) bool { fn isDacEnabled(self: *const Self) bool {
@ -933,8 +861,8 @@ pub fn DmaSound(comptime kind: DmaSoundKind) type {
if (self.fifo.readItem()) |sample| self.sample = @bitCast(i8, sample); if (self.fifo.readItem()) |sample| self.sample = @bitCast(i8, sample);
} }
pub fn amplitude(self: *const Self) i16 { pub fn amplitude(self: *const Self) f32 {
return @as(i16, self.sample); return @intToFloat(f32, self.sample) / 127.5 - (1 / 255);
} }
}; };
} }
@ -1172,7 +1100,7 @@ const SquareWave = struct {
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, @as(u64, self.timer) * tickInterval); self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, @as(u64, self.timer) * tickInterval);
} }
fn sample(self: *const Self, cnt: io.Duty) i8 { fn sample(self: *const Self, cnt: io.Duty) u1 {
const pattern = cnt.pattern.read(); const pattern = cnt.pattern.read();
const i = self.pos ^ 7; // index of 0 should get highest bit const i = self.pos ^ 7; // index of 0 should get highest bit
@ -1183,7 +1111,7 @@ const SquareWave = struct {
0b11 => @as(u8, 0b11111100) >> i, // 75% 0b11 => @as(u8, 0b11111100) >> i, // 75%
}; };
return if (result & 1 == 1) 1 else -1; return @truncate(u1, result);
} }
}; };
@ -1205,8 +1133,8 @@ const Lfsr = struct {
}; };
} }
fn sample(self: *const Self) i8 { fn sample(self: *const Self) u1 {
return if ((~self.shift & 1) == 1) 1 else -1; return @truncate(u1, ~self.shift);
} }
fn updateLength(_: *Self, fs: *const FrameSequencer, ch4: *Noise, new: io.NoiseControl) void { fn updateLength(_: *Self, fs: *const FrameSequencer, ch4: *Noise, new: io.NoiseControl) void {

87
src/emu.zig
View File

@ -1,17 +1,14 @@
const std = @import("std"); const std = @import("std");
const SDL = @import("sdl2");
const Bus = @import("Bus.zig"); const Bus = @import("Bus.zig");
const Scheduler = @import("scheduler.zig").Scheduler; const Scheduler = @import("scheduler.zig").Scheduler;
const Arm7tdmi = @import("cpu.zig").Arm7tdmi; const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
const FpsTracker = @import("util.zig").FpsTracker; const EmulatorFps = @import("util.zig").EmulatorFps;
const Timer = std.time.Timer; const Timer = std.time.Timer;
const Thread = std.Thread; const Thread = std.Thread;
const Atomic = std.atomic.Atomic; const Atomic = std.atomic.Atomic;
const audio_sync = true;
// 228 Lines which consist of 308 dots (which are 4 cycles long) // 228 Lines which consist of 308 dots (which are 4 cycles long)
const cycles_per_frame: u64 = 228 * (308 * 4); //280896 const cycles_per_frame: u64 = 228 * (308 * 4); //280896
const clock_rate: u64 = 1 << 24; // 16.78MHz const clock_rate: u64 = 1 << 24; // 16.78MHz
@ -35,9 +32,7 @@ const RunKind = enum {
LimitedBusy, LimitedBusy,
}; };
pub fn run(kind: RunKind, quit: *Atomic(bool), fps: *FpsTracker, sched: *Scheduler, cpu: *Arm7tdmi) void { pub fn run(kind: RunKind, quit: *Atomic(bool), fps: *EmulatorFps, sched: *Scheduler, cpu: *Arm7tdmi) void {
if (audio_sync) log.info("Audio sync enabled", .{});
switch (kind) { switch (kind) {
.Unlimited => runUnsynchronized(quit, sched, cpu, null), .Unlimited => runUnsynchronized(quit, sched, cpu, null),
.Limited => runSynchronized(quit, sched, cpu, null), .Limited => runSynchronized(quit, sched, cpu, null),
@ -61,78 +56,50 @@ pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi) void {
} }
} }
fn syncToAudio(cpu: *const Arm7tdmi) void { pub fn runUnsynchronized(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, fps: ?*EmulatorFps) void {
const stream = cpu.bus.apu.stream;
const min_sample_count = 0x800;
// Busy Loop while we wait for the Audio system to catch up
while (SDL.SDL_AudioStreamAvailable(stream) > (@sizeOf(u16) * 2) * min_sample_count) {}
}
pub fn runUnsynchronized(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, fps: ?*FpsTracker) void {
log.info("Emulation thread w/out video sync", .{});
if (fps) |tracker| { if (fps) |tracker| {
log.info("FPS Tracking Enabled", .{}); log.info("Start unsynchronized emu thread w/ fps tracking", .{});
while (!quit.load(.SeqCst)) { while (!quit.load(.SeqCst)) {
runFrame(sched, cpu); runFrame(sched, cpu);
if (audio_sync) syncToAudio(cpu);
tracker.completeFrame(); tracker.completeFrame();
} }
} else { } else {
while (!quit.load(.SeqCst)) { log.info("Start unsynchronized emu thread", .{});
runFrame(sched, cpu); while (!quit.load(.SeqCst)) runFrame(sched, cpu);
if (audio_sync) syncToAudio(cpu);
}
} }
} }
pub fn runSynchronized(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, fps: ?*FpsTracker) void { pub fn runSynchronized(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, fps: ?*EmulatorFps) void {
log.info("Emulation thread w/ video sync", .{});
var timer = Timer.start() catch unreachable; var timer = Timer.start() catch unreachable;
var wake_time: u64 = frame_period; var wake_time: u64 = frame_period;
if (fps) |tracker| { if (fps) |tracker| {
log.info("FPS Tracking Enabled", .{}); log.info("Start synchronized emu thread w/ fps tracking", .{});
while (!quit.load(.SeqCst)) { while (!quit.load(.SeqCst)) {
runFrame(sched, cpu); runSyncCore(sched, cpu, &timer, &wake_time);
const new_wake_time = syncToVideo(&timer, wake_time);
// Spin to make up the difference of OS scheduler innacuracies
// If we happen to also be syncing to audio, we choose to spin on
// the amount of time needed for audio to catch up rather than
// our expected wake-up time
if (audio_sync) syncToAudio(cpu) else spinLoop(&timer, wake_time);
wake_time = new_wake_time;
tracker.completeFrame(); tracker.completeFrame();
} }
} else { } else {
while (!quit.load(.SeqCst)) { log.info("Start synchronized emu thread", .{});
runFrame(sched, cpu); while (!quit.load(.SeqCst)) runSyncCore(sched, cpu, &timer, &wake_time);
const new_wake_time = syncToVideo(&timer, wake_time);
// see above comment
if (audio_sync) syncToAudio(cpu) else spinLoop(&timer, wake_time);
wake_time = new_wake_time;
}
} }
} }
inline fn syncToVideo(timer: *Timer, wake_time: u64) u64 { inline fn runSyncCore(sched: *Scheduler, cpu: *Arm7tdmi, timer: *Timer, wake_time: *u64) void {
// Use the OS scheduler to put the emulation thread to sleep runFrame(sched, cpu);
const maybe_recalc_wake_time = sleep(timer, wake_time);
// If sleep() determined we need to adjust our wake up time, do so // Put the Thread to Sleep + Backup Spin Loop
// otherwise predict our next wake up time according to the frame period // This saves on resource usage when frame limiting
return if (maybe_recalc_wake_time) |recalc| recalc else wake_time + frame_period; sleep(timer, wake_time);
// Update to the new wake time
wake_time.* += frame_period;
} }
pub fn runBusyLoop(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi) void { pub fn runBusyLoop(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi) void {
log.info("Emulation thread with video sync using busy loop", .{}); log.info("Start synchronized emu thread using busy loop", .{});
var timer = Timer.start() catch unreachable; var timer = Timer.start() catch unreachable;
var wake_time: u64 = frame_period; var wake_time: u64 = frame_period;
@ -145,17 +112,21 @@ pub fn runBusyLoop(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi) void
} }
} }
fn sleep(timer: *Timer, wake_time: u64) ?u64 { fn sleep(timer: *Timer, wake_time: *u64) void {
// const step = std.time.ns_per_ms * 10; // 10ms // const step = std.time.ns_per_ms * 10; // 10ms
const timestamp = timer.read(); const timestamp = timer.read();
// ns_late is non zero if we are late. // ns_late is non zero if we are late.
const ns_late = timestamp -| wake_time; const ns_late = timestamp -| wake_time.*;
// If we're more than a frame late, skip the rest of this loop // If we're more than a frame late, skip the rest of this loop
// Recalculate what our new wake time should be so that we can // Recalculate what our new wake time should be so that we can
// get "back on track" // get "back on track"
if (ns_late > frame_period) return timestamp + frame_period; if (ns_late > frame_period) {
wake_time.* = timestamp + frame_period;
return;
}
const sleep_for = frame_period - ns_late; const sleep_for = frame_period - ns_late;
// // Employ several sleep calls in periods of 10ms // // Employ several sleep calls in periods of 10ms
@ -168,7 +139,9 @@ fn sleep(timer: *Timer, wake_time: u64) ?u64 {
std.time.sleep(sleep_for); std.time.sleep(sleep_for);
return null; // Spin to make up the difference if there is a need
// Make sure that we're using the old wake time and not the onne we recalculated
spinLoop(timer, wake_time.*);
} }
fn spinLoop(timer: *Timer, wake_time: u64) void { fn spinLoop(timer: *Timer, wake_time: u64) void {

131
src/main.zig
View File

@ -9,7 +9,7 @@ const Bus = @import("Bus.zig");
const Apu = @import("apu.zig").Apu; const Apu = @import("apu.zig").Apu;
const Arm7tdmi = @import("cpu.zig").Arm7tdmi; const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
const Scheduler = @import("scheduler.zig").Scheduler; const Scheduler = @import("scheduler.zig").Scheduler;
const FpsTracker = @import("util.zig").FpsTracker; const EmulatorFps = @import("util.zig").EmulatorFps;
const Timer = std.time.Timer; const Timer = std.time.Timer;
const Thread = std.Thread; const Thread = std.Thread;
@ -31,61 +31,65 @@ pub const log_level = if (builtin.mode != .Debug) .info else std.log.default_lev
const asString = @import("util.zig").asString; const asString = @import("util.zig").asString;
// CLI Arguments + Help Text pub fn main() anyerror!void {
const params = clap.parseParamsComptime( // Allocator for Emulator + CLI
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
const alloc = gpa.allocator();
defer std.debug.assert(!gpa.deinit());
// CLI Arguments
const params = comptime clap.parseParamsComptime(
\\-h, --help Display this help and exit. \\-h, --help Display this help and exit.
\\-b, --bios <str> Optional path to a GBA BIOS ROM. \\-b, --bios <str> Optional path to a GBA BIOS ROM.
\\<str> Path to the GBA GamePak ROM \\<str> Path to the GBA GamePak ROM
\\ \\
); );
pub fn main() anyerror!void {
// Allocator for Emulator + CLI
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer std.debug.assert(!gpa.deinit());
const alloc = gpa.allocator();
// Setup CLI using zig-clap
var res = try clap.parse(clap.Help, &params, clap.parsers.default, .{}); var res = try clap.parse(clap.Help, &params, clap.parsers.default, .{});
defer res.deinit(); defer res.deinit();
const stderr = std.io.getStdErr(); const stderr = std.io.getStdErr();
defer stderr.close(); defer stderr.close();
// Display Help, if requested
// Grab ROM and BIOS paths if provided
if (res.args.help) return clap.help(stderr.writer(), clap.Help, &params, .{}); if (res.args.help) return clap.help(stderr.writer(), clap.Help, &params, .{});
const rom_path = try getRomPath(res, stderr);
const bios_path: ?[]const u8 = if (res.args.bios) |p| p else null; const bios_path: ?[]const u8 = if (res.args.bios) |p| p else null;
const rom_path = switch (res.positionals.len) {
1 => res.positionals[0],
0 => {
try stderr.writeAll("ZBA requires a positional path to a GamePak ROM.\n");
return CliError.InsufficientOptions;
},
else => {
try stderr.writeAll("ZBA received too many arguments.\n");
return CliError.UnneededOptions;
},
};
// Determine Save Directory // Determine Save Directory
const save_dir = try getSavePath(alloc); const save_dir = try setupSavePath(alloc);
defer if (save_dir) |path| alloc.free(path); defer if (save_dir) |path| alloc.free(path);
log.info("Found save directory: {s}", .{save_dir}); log.info("Found save directory: {s}", .{save_dir});
// Initialize Scheduler and ARM7TDMI Emulator // Initialize SDL
// Provide GBA Bus (initialized with ARM7TDMI) with a valid ptr to ARM7TDMI _ = initSdl2();
defer SDL.SDL_Quit();
// Initialize Emulator
var scheduler = Scheduler.init(alloc); var scheduler = Scheduler.init(alloc);
defer scheduler.deinit(); defer scheduler.deinit();
const paths = .{ .bios = bios_path, .rom = rom_path, .save = save_dir }; const paths = .{ .bios = bios_path, .rom = rom_path, .save = save_dir };
var cpu = try Arm7tdmi.init(alloc, &scheduler, paths); var cpu = try Arm7tdmi.init(alloc, &scheduler, paths);
defer cpu.deinit(); defer cpu.deinit();
cpu.bus.attach(&cpu); cpu.bus.attach(&cpu);
// cpu.fastBoot(); // Uncomment to skip BIOS // cpu.fastBoot();
// Copy ROM title while Emulator still belongs to this thread // Initialize SDL Audio
const title = cpu.bus.pak.title; const audio_dev = initAudio(&cpu.bus.apu);
defer SDL.SDL_CloseAudioDevice(audio_dev);
// Initialize SDL2
initSdl2();
defer SDL.SDL_Quit();
const dev = initAudio(&cpu.bus.apu);
defer SDL.SDL_CloseAudioDevice(dev);
// TODO: Refactor or delete this Logging code
// I probably still need logging in some form though (e.g. Golden Sun IIRC)
const log_file: ?File = if (enable_logging) blk: { const log_file: ?File = if (enable_logging) blk: {
const file = try std.fs.cwd().createFile(if (is_binary) "zba.bin" else "zba.log", .{}); const file = try std.fs.cwd().createFile(if (is_binary) "zba.bin" else "zba.log", .{});
cpu.useLogger(&file, is_binary); cpu.useLogger(&file, is_binary);
@ -93,17 +97,16 @@ pub fn main() anyerror!void {
} else null; } else null;
defer if (log_file) |file| file.close(); defer if (log_file) |file| file.close();
// Init Atomics
var quit = Atomic(bool).init(false); var quit = Atomic(bool).init(false);
var emu_rate = FpsTracker.init(); var emu_rate = EmulatorFps.init();
// Run Emulator in it's separate thread // Create Emulator Thread
// From this point on, interacting with Arm7tdmi or Scheduler
// be justified, as it will require to be thread-afe
const emu_thread = try Thread.spawn(.{}, emu.run, .{ .LimitedFPS, &quit, &emu_rate, &scheduler, &cpu }); const emu_thread = try Thread.spawn(.{}, emu.run, .{ .LimitedFPS, &quit, &emu_rate, &scheduler, &cpu });
defer emu_thread.join(); defer emu_thread.join();
var title_buf: [0x20]u8 = std.mem.zeroes([0x20]u8); var title_buf: [0x20]u8 = std.mem.zeroes([0x20]u8);
const window_title = try std.fmt.bufPrint(&title_buf, "ZBA | {s}", .{asString(title)}); const window_title = try std.fmt.bufPrint(&title_buf, "ZBA | {s}", .{asString(cpu.bus.pak.title)});
const window = createWindow(window_title, gba_width, gba_height); const window = createWindow(window_title, gba_width, gba_height);
defer SDL.SDL_DestroyWindow(window); defer SDL.SDL_DestroyWindow(window);
@ -155,7 +158,7 @@ pub fn main() anyerror!void {
SDL.SDLK_s => io.keyinput.shoulder_r.set(), SDL.SDLK_s => io.keyinput.shoulder_r.set(),
SDL.SDLK_RETURN => io.keyinput.start.set(), SDL.SDLK_RETURN => io.keyinput.start.set(),
SDL.SDLK_RSHIFT => io.keyinput.select.set(), SDL.SDLK_RSHIFT => io.keyinput.select.set(),
SDL.SDLK_i => std.debug.print("{} samples\n", .{@intCast(u32, SDL.SDL_AudioStreamAvailable(cpu.bus.apu.stream)) / (2 * @sizeOf(u16))}), SDL.SDLK_i => std.debug.print("{} samples\n", .{@intCast(u32, SDL.SDL_AudioStreamAvailable(cpu.bus.apu.stream)) / (2 * @sizeOf(f32))}),
else => {}, else => {},
} }
}, },
@ -186,9 +189,31 @@ fn sdlPanic() noreturn {
@panic(std.mem.sliceTo(str, 0)); @panic(std.mem.sliceTo(str, 0));
} }
fn initSdl2() void { // FIXME: Superfluous allocations?
fn setupSavePath(alloc: std.mem.Allocator) !?[]const u8 {
const save_subpath = try std.fs.path.join(alloc, &[_][]const u8{ "zba", "save" });
defer alloc.free(save_subpath);
const maybe_data_path = try known_folders.getPath(alloc, .data);
defer if (maybe_data_path) |path| alloc.free(path);
const save_path = if (maybe_data_path) |base| try std.fs.path.join(alloc, &[_][]const u8{ base, save_subpath }) else null;
if (save_path) |_| {
// If we've determined what our save path should be, ensure the prereq directories
// are present so that we can successfully write to the path when necessary
const maybe_data_dir = try known_folders.open(alloc, .data, .{});
if (maybe_data_dir) |data_dir| try data_dir.makePath(save_subpath);
}
return save_path;
}
fn initSdl2() c_int {
const status = SDL.SDL_Init(SDL.SDL_INIT_VIDEO | SDL.SDL_INIT_EVENTS | SDL.SDL_INIT_AUDIO | SDL.SDL_INIT_GAMECONTROLLER); const status = SDL.SDL_Init(SDL.SDL_INIT_VIDEO | SDL.SDL_INIT_EVENTS | SDL.SDL_INIT_AUDIO | SDL.SDL_INIT_GAMECONTROLLER);
if (status < 0) sdlPanic(); if (status < 0) sdlPanic();
return status;
} }
fn createWindow(title: []u8, width: c_int, height: c_int) *SDL.SDL_Window { fn createWindow(title: []u8, width: c_int, height: c_int) *SDL.SDL_Window {
@ -220,7 +245,7 @@ fn initAudio(apu: *Apu) SDL.SDL_AudioDeviceID {
var have: SDL.SDL_AudioSpec = undefined; var have: SDL.SDL_AudioSpec = undefined;
var want: SDL.SDL_AudioSpec = .{ var want: SDL.SDL_AudioSpec = .{
.freq = sample_rate, .freq = sample_rate,
.format = SDL.AUDIO_U16, .format = SDL.AUDIO_F32,
.channels = 2, .channels = 2,
.samples = 0x100, .samples = 0x100,
.callback = audioCallback, .callback = audioCallback,
@ -243,35 +268,3 @@ export fn audioCallback(userdata: ?*anyopaque, stream: [*c]u8, len: c_int) void
const apu = @ptrCast(*Apu, @alignCast(8, userdata)); const apu = @ptrCast(*Apu, @alignCast(8, userdata));
_ = SDL.SDL_AudioStreamGet(apu.stream, stream, len); _ = SDL.SDL_AudioStreamGet(apu.stream, stream, len);
} }
fn getSavePath(alloc: std.mem.Allocator) !?[]const u8 {
const save_subpath = "zba" ++ [_]u8{std.fs.path.sep} ++ "save";
const maybe_data_path = try known_folders.getPath(alloc, .data);
defer if (maybe_data_path) |path| alloc.free(path);
const save_path = if (maybe_data_path) |base| try std.fs.path.join(alloc, &[_][]const u8{ base, "zba", "save" }) else null;
if (save_path) |_| {
// If we've determined what our save path should be, ensure the prereq directories
// are present so that we can successfully write to the path when necessary
const maybe_data_dir = try known_folders.open(alloc, .data, .{});
if (maybe_data_dir) |data_dir| try data_dir.makePath(save_subpath);
}
return save_path;
}
fn getRomPath(res: clap.Result(clap.Help, &params, clap.parsers.default), stderr: std.fs.File) ![]const u8 {
return switch (res.positionals.len) {
1 => res.positionals[0],
0 => {
try stderr.writeAll("ZBA requires a positional path to a GamePak ROM.\n");
return CliError.InsufficientOptions;
},
else => {
try stderr.writeAll("ZBA received too many arguments.\n");
return CliError.UnneededOptions;
},
};
}

2
src/util.zig
View File

@ -17,7 +17,7 @@ pub inline fn rotr(comptime T: type, x: T, r: anytype) T {
return x >> ar | x << (1 +% ~ar); return x >> ar | x << (1 +% ~ar);
} }
pub const FpsTracker = struct { pub const EmulatorFps = struct {
const Self = @This(); const Self = @This();
fps: u32, fps: u32,