diff --git a/src/emu.zig b/src/emu.zig index fbe9a93..b5b5b61 100644 --- a/src/emu.zig +++ b/src/emu.zig @@ -9,12 +9,19 @@ const Timer = std.time.Timer; const Thread = std.Thread; const Atomic = std.atomic.Atomic; -// One frame operates at 59.7275005696Hz -const cycles_per_frame: u64 = 228 * (308 * 4); -const clock_rate: u64 = 1 << 24; +// 228 Lines which consist of 308 dots (which are 4 cycles long) +const cycles_per_frame: u64 = 228 * (308 * 4); //280896 +const clock_rate: u64 = 1 << 24; // 16.78MHz + +// TODO: Don't truncate this, be more accurate w/ timing +// 59.6046447754ns (truncated to just 59ns) const clock_period: u64 = std.time.ns_per_s / clock_rate; const frame_period = (clock_period * cycles_per_frame); +// 59.7275005696Hz +pub const frame_rate = @intToFloat(f64, std.time.ns_per_s) / + ((@intToFloat(f64, std.time.ns_per_s) / @intToFloat(f64, clock_rate)) * @intToFloat(f64, cycles_per_frame)); + const log = std.log.scoped(.Emulation); const RunKind = enum { @@ -27,9 +34,9 @@ const RunKind = enum { pub fn run(kind: RunKind, quit: *Atomic(bool), fps: *FpsAverage, sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { switch (kind) { - .Unlimited => runUnSync(quit, sched, cpu, bus), + .Unlimited => runUnsync(quit, sched, cpu, bus), .Limited => runSync(quit, sched, cpu, bus), - .UnlimitedFPS => runUnSyncFps(quit, fps, sched, cpu, bus), + .UnlimitedFPS => runUnsyncFps(quit, fps, sched, cpu, bus), .LimitedFPS => runSyncFps(quit, fps, sched, cpu, bus), .LimitedBusy => runBusyLoop(quit, sched, cpu, bus), } @@ -47,7 +54,7 @@ pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { } } -pub fn runUnSync(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { +pub fn runUnsync(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { log.info("Unsynchronized EmuThread has begun", .{}); while (!quit.load(.Unordered)) runFrame(sched, cpu, bus); } @@ -69,13 +76,13 @@ pub fn runSync(quit: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus } } -pub fn runUnSyncFps(quit: *Atomic(bool), fps: *FpsAverage, sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { +pub fn runUnsyncFps(quit: *Atomic(bool), fps: *FpsAverage, sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { log.info("Unsynchronized EmuThread with FPS Tracking has begun", .{}); var fps_timer = Timer.start() catch unreachable; while (!quit.load(.Unordered)) { runFrame(sched, cpu, bus); - fps.add(emuFps(fps_timer.lap())); + fps.add(fps_timer.lap()); } } @@ -93,7 +100,7 @@ pub fn runSyncFps(quit: *Atomic(bool), fps: *FpsAverage, sched: *Scheduler, cpu: sleep(&timer, &wake_time); // Determine FPS - fps.add(emuFps(fps_timer.lap())); + fps.add(fps_timer.lap()); // Update to the new wake time wake_time += frame_period; @@ -149,8 +156,3 @@ fn sleep(timer: *Timer, wake_time: *u64) void { fn spinLoop(timer: *Timer, wake_time: u64) void { while (true) if (timer.read() > wake_time) break; } - -inline fn emuFps(left: u64) u64 { - @setRuntimeSafety(false); - return @floatToInt(u64, @intToFloat(f64, std.time.ns_per_s) / @intToFloat(f64, left)); -} diff --git a/src/main.zig b/src/main.zig index 7c4bb15..8a723f6 100644 --- a/src/main.zig +++ b/src/main.zig @@ -17,6 +17,7 @@ const window_scale = 3; const gba_width = @import("ppu.zig").width; const gba_height = @import("ppu.zig").height; const framebuf_pitch = @import("ppu.zig").framebuf_pitch; +const expected_rate = @import("emu.zig").frame_rate; pub const enable_logging: bool = false; const is_binary: bool = false; @@ -76,10 +77,10 @@ pub fn main() anyerror!void { // Init Atomics var quit = Atomic(bool).init(false); - var emu_fps = FpsAverage.init(); + var emu_rate = FpsAverage.init(); // Create Emulator Thread - const emu_thread = try Thread.spawn(.{}, emu.run, .{ .UnlimitedFPS, &quit, &emu_fps, &scheduler, &cpu, &bus }); + const emu_thread = try Thread.spawn(.{}, emu.run, .{ .LimitedFPS, &quit, &emu_rate, &scheduler, &cpu, &bus }); defer emu_thread.join(); // Initialize SDL @@ -161,8 +162,8 @@ pub fn main() anyerror!void { _ = SDL.SDL_RenderCopy(renderer, texture, null, null); SDL.SDL_RenderPresent(renderer); - const avg = emu_fps.calc(); - const dyn_title = std.fmt.bufPrint(&dyn_title_buf, "{s} [Emu: {d:0>3}fps, {d:0>3}%] ", .{ title, avg, (avg * 100 / 59) }) catch unreachable; + const actual = emu_rate.calc(); + const dyn_title = std.fmt.bufPrint(&dyn_title_buf, "{s} [Emu: {d:0>3.2}fps, {d:0>3.2}%] ", .{ title, actual, actual * 100 / expected_rate }) catch unreachable; SDL.SDL_SetWindowTitle(window, dyn_title.ptr); } diff --git a/src/util.zig b/src/util.zig index 7880a5a..1f3e260 100644 --- a/src/util.zig +++ b/src/util.zig @@ -33,8 +33,8 @@ pub const FpsAverage = struct { self.sample_count += 1; } - pub fn calc(self: *const Self) u64 { - return self.total / self.sample_count; + pub fn calc(self: *const Self) f64 { + return @intToFloat(f64, std.time.ns_per_s) / (@intToFloat(f64, self.total) / @intToFloat(f64, self.sample_count)); } fn reset(self: *Self, sample: u64) void {