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fix: clean up frequency timer implementations

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-05-21 14:21:50 -03:00
parent 5164aa961d
commit 109561310e
1 changed files with 18 additions and 22 deletions
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40
src/apu.zig
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@ -966,24 +966,20 @@ const WaveDevice = struct {
fn reloadTimer(self: *Self, value: u11) void { fn reloadTimer(self: *Self, value: u11) void {
self.sched.removeScheduledEvent(.{ .ApuChannel = 2 }); self.sched.removeScheduledEvent(.{ .ApuChannel = 2 });
const timer = (2048 - @as(u64, value)) * 4;
self.timer = @truncate(u11, timer);
self.sched.push(.{ .ApuChannel = 2 }, timer * tickInterval); self.timer = (@as(u16, 2048) - value) * 2;
self.sched.push(.{ .ApuChannel = 2 }, @as(u64, self.timer) * tickInterval);
} }
fn handleTimerOverflow(self: *Self, cnt_freq: io.Frequency, cnt_sel: io.WaveSelect, late: u64) void { fn handleTimerOverflow(self: *Self, cnt_freq: io.Frequency, cnt_sel: io.WaveSelect, late: u64) void {
const timer = (2048 - @as(u64, cnt_freq.frequency.read())) * 2;
self.timer = @truncate(u12, timer);
if (cnt_sel.dimension.read()) { if (cnt_sel.dimension.read()) {
self.offset = (self.offset + 1) % 0x40; // 0x20 bytes (both banks), which contain 2 samples each self.offset = (self.offset + 1) % 0x40; // 0x20 bytes (both banks), which contain 2 samples each
} else { } else {
self.offset = (self.offset + 1) % 0x20; // 0x10 bytes, which contain 2 samples each self.offset = (self.offset + 1) % 0x20; // 0x10 bytes, which contain 2 samples each
} }
self.sched.push(.{ .ApuChannel = 2 }, timer * tickInterval -| late); self.timer = (@as(u16, 2048) - cnt_freq.frequency.read()) * 2;
self.sched.push(.{ .ApuChannel = 2 }, @as(u64, self.timer) * tickInterval -| late);
} }
fn sample(self: *const Self, cnt: io.WaveSelect) u4 { fn sample(self: *const Self, cnt: io.WaveSelect) u4 {
@ -1046,7 +1042,7 @@ const SquareWave = struct {
pos: u3, pos: u3,
sched: *Scheduler, sched: *Scheduler,
timer: u12, timer: u16,
pub fn init(sched: *Scheduler) Self { pub fn init(sched: *Scheduler) Self {
return .{ return .{
@ -1089,22 +1085,19 @@ const SquareWave = struct {
} }
fn handleTimerOverflow(self: *Self, comptime kind: ChannelKind, cnt: io.Frequency, late: u64) void { fn handleTimerOverflow(self: *Self, comptime kind: ChannelKind, cnt: io.Frequency, late: u64) void {
const timer = (2048 - @as(u64, cnt.frequency.read())) * 4;
self.timer = @truncate(u12, timer);
self.pos +%= 1; self.pos +%= 1;
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, timer * tickInterval -| late); self.timer = (@as(u16, 2048) - cnt.frequency.read()) * 4;
self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, @as(u64, self.timer) * tickInterval -| late);
} }
fn reloadTimer(self: *Self, comptime kind: ChannelKind, value: u11) void { fn reloadTimer(self: *Self, comptime kind: ChannelKind, value: u11) void {
self.sched.removeScheduledEvent(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }); self.sched.removeScheduledEvent(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 });
const tmp: u64 = (2048 - @as(u64, value)) * 4; // What Freq Timer should be assuming no weird behaviour const tmp = (@as(u16, 2048) - 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 = (tmp & ~@as(u16, 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 }, 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) u1 { fn sample(self: *const Self, cnt: io.Duty) u1 {
@ -1163,14 +1156,17 @@ const Lfsr = struct {
self.sched.removeScheduledEvent(.{ .ApuChannel = 3 }); self.sched.removeScheduledEvent(.{ .ApuChannel = 3 });
const div = Self.divisor(poly.div_ratio.read()); const div = Self.divisor(poly.div_ratio.read());
const timer = @as(u64, div << poly.shift.read()); const timer = div << poly.shift.read();
self.sched.push(.{ .ApuChannel = 3 }, @as(u64, timer) * tickInterval);
self.sched.push(.{ .ApuChannel = 3 }, timer * tickInterval);
} }
fn handleTimerOverflow(self: *Self, poly: io.PolyCounter, late: u64) void { fn handleTimerOverflow(self: *Self, poly: io.PolyCounter, late: u64) void {
// Obscure: "Using a noise channel clock shift of 14 or 15
// results in the LFSR receiving no clocks."
if (poly.shift.read() >= 14) return;
const div = Self.divisor(poly.div_ratio.read()); const div = Self.divisor(poly.div_ratio.read());
const timer = @as(u64, div << poly.shift.read()); const timer = div << poly.shift.read();
const tmp = (self.shift & 1) ^ ((self.shift & 2) >> 1); const tmp = (self.shift & 1) ^ ((self.shift & 2) >> 1);
self.shift = (self.shift >> 1) | (tmp << 14); self.shift = (self.shift >> 1) | (tmp << 14);
@ -1178,7 +1174,7 @@ const Lfsr = struct {
if (poly.width.read()) if (poly.width.read())
self.shift = (self.shift & ~@as(u15, 0x40)) | tmp << 6; self.shift = (self.shift & ~@as(u15, 0x40)) | tmp << 6;
self.sched.push(.{ .ApuChannel = 3 }, timer * tickInterval -| late); self.sched.push(.{ .ApuChannel = 3 }, @as(u64, timer) * tickInterval -| late);
} }
fn divisor(code: u3) u16 { fn divisor(code: u3) u16 {