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feat: implement PPU Timings in Scheduler

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This commit is contained in:
Rekai Nyangadzayi Musuka
2022-01-05 21:18:33 -04:00
parent f709458638
commit c6123d8a6d
3 changed files with 59 additions and 7 deletions
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47
src/scheduler.zig
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@@ -25,7 +25,7 @@ pub const Scheduler = struct {
self.queue.deinit();
}
pub fn handleEvent(self: *@This(), _: *Arm7tdmi, _: *Bus) void {
pub fn handleEvent(self: *@This(), _: *Arm7tdmi, bus: *Bus) void {
const should_handle = if (self.queue.peek()) |e| self.tick >= e.tick else false;
if (should_handle) {
@@ -36,15 +36,55 @@ pub const Scheduler = struct {
std.debug.panic("[Scheduler] Somehow, a u64 overflowed", .{});
},
.HBlank => {
std.debug.panic("[Scheduler] tick {}: Hblank", .{self.tick});
std.log.debug("[Scheduler] tick {}: Hblank", .{self.tick});
// We've reached the end of a scanline
const scanline = bus.io.vcount.scanline.read();
bus.io.vcount.scanline.write(scanline + 1);
bus.io.dispstat.hblank.set();
if (scanline < 160) {
self.push(.{ .kind = .Visible, .tick = self.tick + (68 * 4) });
} else {
self.push(.{ .kind = .VBlank, .tick = self.tick + (68 * 4) });
}
},
.Visible => {
std.log.debug("[Scheduler] tick {}: Visible", .{self.tick});
// Beginning of a Scanline
bus.io.dispstat.hblank.unset();
bus.io.dispstat.vblank.unset();
self.push(.{ .kind = .HBlank, .tick = self.tick + (240 * 4) });
},
.VBlank => {
std.debug.panic("[Scheduler] tick {}: VBlank", .{self.tick});
std.log.debug("[Scheduler] tick {}: VBlank", .{self.tick});
// Beginning of a Scanline, not visible though
bus.io.dispstat.hblank.unset();
bus.io.dispstat.vblank.set();
const scanline = bus.io.vcount.scanline.read();
bus.io.vcount.scanline.write(scanline + 1);
if (scanline < 227) {
// Another Vblank Scanline
self.push(.{ .kind = .VBlank, .tick = self.tick + 68 * (308 * 4) });
} else {
bus.io.vcount.scanline.write(0); // Reset Scanline
self.push(.{ .kind = .Visible, .tick = self.tick + 68 * (308 * 4) });
}
},
}
}
}
pub inline fn push(self: *@This(), event: Event) void {
self.queue.add(event) catch unreachable;
}
pub inline fn nextTimestamp(self: *@This()) u64 {
if (self.queue.peek()) |e| {
return e.tick;
@@ -65,4 +105,5 @@ pub const EventKind = enum {
HeatDeath,
HBlank,
VBlank,
Visible,
};