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-rw-r--r--emu8910.js392
1 files changed, 183 insertions, 209 deletions
diff --git a/emu8910.js b/emu8910.js
index e168e25..005fd11 100644
--- a/emu8910.js
+++ b/emu8910.js
@@ -1,6 +1,7 @@
+"use strict";
/**
- * @file emu8910.js
- * @brief Tiny AY8910 PSG Emulator - emu8910.js
+ * @file emu8910.ts
+ * @brief Tiny AY8910 PSG Emulator - emu8910.ts
*
* Author: Dylan Müller
*
@@ -48,94 +49,38 @@
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
-
-var YM_CLOCK_ZX = 1750000;
-var FIR = [-0.011368,
- 0.004512,
- 0.008657,
- -0.011763,
- -0.000000,
- 0.012786,
- -0.010231,
- -0.005801,
- 0.015915,
- -0.006411,
- -0.012504,
- 0.017299,
- -0.000000,
- -0.019605,
- 0.016077,
- 0.009370,
- -0.026526,
- 0.011074,
- 0.022508,
- -0.032676,
- 0.000000,
- 0.042011,
- -0.037513,
- -0.024362,
- 0.079577,
- -0.040604,
- -0.112540,
- 0.294080,
- 0.625000,
- 0.294080,
- -0.112540,
- -0.040604,
- 0.079577,
- -0.024362,
- -0.037513,
- 0.042011,
- 0.000000,
- -0.032676,
- 0.022508,
- 0.011074,
- -0.026526,
- 0.009370,
- 0.016077,
- -0.019605,
- -0.000000,
- 0.017299,
- -0.012504,
- -0.006411,
- 0.015915,
- -0.005801,
- -0.010231,
- 0.012786,
- -0.000000,
- -0.011763,
- 0.008657,
- 0.004512,
- -0.011368];
-var Interpolator = /** @class */ (function () {
- function Interpolator() {
+const YM_CLOCK_ZX = 1750000;
+const FIR_CUTOFF = 2000; // Hz
+const FIR_TAPS = 200; // N taps
+var FIR = []; // coeff
+class Interpolator {
+ constructor() {
this.buffer = [];
- for (var i = 0; i < 4; i++) {
+ for (let i = 0; i < 4; i++) {
this.buffer[i] = 0x0;
}
}
- Interpolator.prototype.step = function (x) {
- var b = this.buffer;
+ step(x) {
+ let b = this.buffer;
b[0] = b[1];
b[1] = b[2];
b[2] = b[3];
b[3] = x;
- };
- Interpolator.prototype.cubic = function (mu) {
- var b = this.buffer;
- var a0, a1, a2, a3, mu2 = 0;
- mu2 = mu * mu2;
+ }
+ cubic(mu) {
+ let b = this.buffer;
+ let a0, a1, a2, a3, mu2 = 0;
+ mu2 = mu * mu;
a0 = b[3] - b[2] - b[0] + b[1];
a1 = b[0] - b[1] - a0;
a2 = b[2] - b[0];
a3 = b[1];
return (a0 * mu * mu2 + a1 * mu2 + a2 * mu + a3);
- };
- return Interpolator;
-}());
+ }
+}
// DC filter
-var BiasFilter = /** @class */ (function () {
- function BiasFilter(length, attenuate) {
+class BiasFilter {
+ constructor(length, attenuate) {
this.samples = [];
this.index = 0x0;
this.length = 0x0;
@@ -143,16 +88,16 @@ var BiasFilter = /** @class */ (function () {
this.attenuate = 0x0;
this.length = length;
this.sum = 0x0;
- for (var i = 0; i < this.length; i++) {
+ for (let i = 0; i < this.length; i++) {
this.samples[i] = 0x0;
}
this.attenuate = attenuate;
}
- BiasFilter.prototype.step = function (x) {
- var index = this.index;
- var delta = x - this.samples[index];
- var attenuate = this.attenuate;
- var avg = 0x0;
+ step(x) {
+ let index = this.index;
+ let delta = x - this.samples[index];
+ let attenuate = this.attenuate;
+ let avg = 0x0;
this.sum += delta;
this.samples[index] = x;
if (++this.index > (this.length - 1)) {
@@ -160,11 +105,10 @@ var BiasFilter = /** @class */ (function () {
}
avg = this.sum / this.length;
return (x - avg) * (1 / attenuate);
- };
- return BiasFilter;
-}());
-var FirFilter = /** @class */ (function () {
- function FirFilter(h, m) {
+ }
+}
+class FirFilter {
+ constructor(h, m) {
this.buffer = [];
this.index = 0x0;
this.offset = 0x0;
@@ -175,47 +119,50 @@ var FirFilter = /** @class */ (function () {
this.index = 0;
this.m = m;
this.h = h;
- var buffer = this.buffer;
- for (var i = 0; i < this.length * 2; i++) {
+ let buffer = this.buffer;
+ for (let i = 0; i < this.length * 2; i++) {
buffer[i] = 0x0;
}
}
- FirFilter.prototype.step = function (samples) {
- var index = this.index;
- var buffer = this.buffer;
- var length = this.length;
- var m = this.m;
- var h = this.h;
- var y = 0x0;
- var i = 0x0;
- this.offset = length - (index * m);
- var sub = buffer.slice(this.offset);
+ step(samples) {
+ let index = this.index;
+ let buffer = this.buffer;
+ let length = this.length;
+ let m = this.m;
+ let h = this.h;
+ let y = 0x0;
+ let i = 0x0;
+ let sub = [];
+ this.offset = (index * m) % length;
+ // Update the buffer with the current input samples
for (i = 0; i < m; i++) {
- buffer[this.offset + i - 1] = samples[i];
+ buffer[(this.offset + i) % length] = samples[i];
}
+ // Create a 'sub' buffer that contains the most recent 'h.length' values in the circular buffer
for (i = 0; i < h.length; i++) {
- y += h[i] * (sub[i] + sub[h.length - i - 1]);
+ sub[i] = buffer[(this.offset - i + length) % length];
}
- for (i = 0; i < m; i++) {
- buffer[this.offset + length - m + i] = buffer[this.offset + i];
+ // Perform the FIR filtering operation
+ for (i = 0; i < h.length; i++) {
+ y += h[i] * sub[i];
}
- this.index = (index + 1) % (length / m - 1);
+ // Update the index to the next position in the circular buffer
+ this.index = (index + 1) % (length / m);
return y;
- };
- return FirFilter;
-}());
-var AudioDriver = /** @class */ (function () {
- function AudioDriver(host) {
+ }
+}
+class AudioDriver {
+ constructor(host) {
this.frequency = 0x0;
this.update = function (ev) {
- var ch0 = ev.outputBuffer.getChannelData(0);
- var ch1 = ev.outputBuffer.getChannelData(1);
- var host = this.host;
- var filter = this.filter;
- var bias = this.bias;
- var output = [0, 0];
- var port = [0, 0];
- for (var i = 0; i < ch0.length; i++) {
+ let ch0 = ev.outputBuffer.getChannelData(0);
+ let ch1 = ev.outputBuffer.getChannelData(1);
+ let host = this.host;
+ let filter = this.filter;
+ let bias = this.bias;
+ let output = [0, 0];
+ let port = [0, 0];
+ for (let i = 0; i < ch0.length; i++) {
output = host.step();
port[0] = filter[0].step(output[0]);
port[1] = filter[1].step(output[1]);
@@ -224,14 +171,14 @@ var AudioDriver = /** @class */ (function () {
}
}.bind(this);
this.device = new AudioContext();
- var device = this.device;
+ let device = this.device;
this.filter = [
new BiasFilter(1024, 1.25),
new BiasFilter(1024, 1.25),
device.createBiquadFilter(),
device.createBiquadFilter()
];
- var filter = this.filter;
+ let filter = this.filter;
filter[2].type = "lowshelf";
filter[2].frequency.value = 10000;
filter[2].gain.value = 2;
@@ -247,8 +194,7 @@ var AudioDriver = /** @class */ (function () {
this.host = host;
this.bias = 0;
}
- return AudioDriver;
-}());
+}
var PSG49_LUT;
(function (PSG49_LUT) {
PSG49_LUT[PSG49_LUT["A_FINE"] = 0] = "A_FINE";
@@ -266,8 +212,8 @@ var PSG49_LUT;
PSG49_LUT[PSG49_LUT["ENV_COARSE"] = 12] = "ENV_COARSE";
PSG49_LUT[PSG49_LUT["ENV_SHAPE"] = 13] = "ENV_SHAPE";
})(PSG49_LUT || (PSG49_LUT = {}));
-var PSG49 = /** @class */ (function () {
- function PSG49(clockRate, intRate) {
+class PSG49 {
+ constructor(clockRate, intRate) {
// main register file
this.register = {
A_FINE: 0x0, A_COARSE: 0x0,
@@ -292,7 +238,8 @@ var PSG49 = /** @class */ (function () {
new Interpolator(),
new Interpolator()
];
- var m = 8;
+ let m = 8;
+ FIR = this.gen_fir(FIR_TAPS, FIR_CUTOFF, this.driver.device.sampleRate);
this.fir = [
new FirFilter(FIR, m),
new FirFilter(FIR, m)
@@ -307,7 +254,7 @@ var PSG49 = /** @class */ (function () {
this.interrupt = {
frequency: intRate,
cycle: 0,
- routine: function () { }
+ routine: () => { }
};
this.envelope = {
strobe: 0,
@@ -338,30 +285,30 @@ var PSG49 = /** @class */ (function () {
this.build_dac(1.3, 40);
this.build_adsr();
}
- PSG49.prototype.build_dac = function (decay, shift) {
- var dac = this.dac;
- var y = Math.sqrt(decay);
- var z = shift / 31;
+ build_dac(decay, shift) {
+ let dac = this.dac;
+ let y = Math.sqrt(decay);
+ let z = shift / 31;
dac[0] = 0;
dac[1] = 0;
- for (var i = 2; i <= 31; i++) {
+ for (let i = 2; i <= 31; i++) {
dac[i] = 1.0 / Math.pow(y, shift - (z * i));
}
- };
- PSG49.prototype.init_test = function () {
- var r = this.register;
- r.MIXER = 56;
+ }
+ init_test() {
+ let r = this.register;
+ r.MIXER = 0b00111000;
r.A_VOL = 15;
//r.A_VOL |= 0x10;
r.A_FINE = 200;
//r.ENV_COARSE = 200;
- };
- PSG49.prototype.build_adsr = function () {
- var envelope = this.envelope;
- var stub = envelope.stub;
- stub.reset = function (ev) {
- var strobe = ev.strobe;
- var transient = ev.transient;
+ }
+ build_adsr() {
+ let envelope = this.envelope;
+ let stub = envelope.stub;
+ stub.reset = (ev) => {
+ let strobe = ev.strobe;
+ let transient = ev.transient;
switch (ev.offset) {
case 0x4:
transient = 0;
@@ -381,19 +328,19 @@ var PSG49 = /** @class */ (function () {
break;
}
};
- stub.grow = function (ev) {
+ stub.grow = (ev) => {
if (++ev.step > 31) {
ev.strobe ^= 1;
ev.stub.reset(ev);
}
};
- stub.decay = function (ev) {
+ stub.decay = (ev) => {
if (--ev.step < 0) {
ev.strobe ^= 1;
ev.stub.reset(ev);
}
};
- stub.hold = function (ev) { };
+ stub.hold = (ev) => { };
envelope.matrix = [
[stub.decay, stub.hold],
[stub.grow, stub.hold],
@@ -402,9 +349,37 @@ var PSG49 = /** @class */ (function () {
[stub.decay, stub.grow],
[stub.grow, stub.decay],
];
- };
- PSG49.prototype.clamp = function () {
- var r = this.register;
+ }
+ blackman_harris(N) {
+ let window = new Array(N);
+ for (let n = 0; n < N; n++) {
+ window[n] = 0.35875 - 0.48829 * Math.cos(2 * Math.PI * n / (N - 1)) +
+ 0.14128 * Math.cos(4 * Math.PI * n / (N - 1)) -
+ 0.01168 * Math.cos(6 * Math.PI * n / (N - 1));
+ }
+ return window;
+ }
+ gen_fir(num_taps, cutoff, fs) {
+ const window = this.blackman_harris(num_taps); // Blackman-Harris
+ const filter = new Array(num_taps);
+ for (let i = 0; i < num_taps; i++) {
+ // Calculate the ideal filter coefficients (sinc function)
+ const n = i - (num_taps - 1) / 2;
+ // Handle the special case when n == 0 to avoid division by zero
+ if (n === 0) {
+ filter[i] = 2 * Math.PI * cutoff / fs;
+ }
+ else {
+ filter[i] = Math.sin(2 * Math.PI * cutoff * n / fs) / (Math.PI * n);
+ }
+ // Apply window function
+ filter[i] *= window[i];
+ }
+ return filter;
+ }
+ ;
+ clamp() {
+ let r = this.register;
r.A_FINE &= 0xff;
r.B_FINE &= 0xff;
r.C_FINE &= 0xff;
@@ -419,13 +394,13 @@ var PSG49 = /** @class */ (function () {
r.NOISE_PERIOD &= 0x1f;
r.MIXER &= 0x3f;
r.ENV_SHAPE &= 0xff;
- };
- PSG49.prototype.map = function () {
- var r = this.register;
- var channel = this.channels;
- var ev = this.envelope;
- var toneMask = [0x1, 0x2, 0x4];
- var noiseMask = [0x8, 0x10, 0x20];
+ }
+ map() {
+ let r = this.register;
+ let channel = this.channels;
+ let ev = this.envelope;
+ let toneMask = [0x1, 0x2, 0x4];
+ let noiseMask = [0x8, 0x10, 0x20];
this.clamp();
// update tone channel period
channel[0].period = r.A_FINE | r.A_COARSE << 8;
@@ -434,12 +409,12 @@ var PSG49 = /** @class */ (function () {
channel[0].volume = r.A_VOL & 0xf;
channel[1].volume = r.B_VOL & 0xf;
channel[2].volume = r.C_VOL & 0xf;
- for (var i = 0; i < 3; i++) {
- var bit = r.MIXER & toneMask[i];
+ for (let i = 0; i < 3; i++) {
+ let bit = r.MIXER & toneMask[i];
channel[i].tone = bit ? 1 : 0;
}
- for (var i = 0; i < 3; i++) {
- var bit = r.MIXER & noiseMask[i];
+ for (let i = 0; i < 3; i++) {
+ let bit = r.MIXER & noiseMask[i];
channel[i].noise = bit ? 1 : 0;
}
channel[0].envelope = (r.A_VOL & 0x10) ? 0 : 1;
@@ -496,12 +471,12 @@ var PSG49 = /** @class */ (function () {
ev.stub.reset(ev);
}
ev.store = r.ENV_SHAPE;
- };
- PSG49.prototype.step_tone = function (index) {
- var ch = this.channels[index % 3];
- var step = this.clock.step;
- var port = ch.port;
- var period = (ch.period == 0x0) ? 0x1 : ch.period;
+ }
+ step_tone(index) {
+ let ch = this.channels[index % 3];
+ let step = this.clock.step;
+ let port = ch.port;
+ let period = (ch.period == 0x0) ? 0x1 : ch.period;
ch.counter += step;
if (ch.counter >= period) {
// 50% duty cycle
@@ -510,22 +485,22 @@ var PSG49 = /** @class */ (function () {
ch.counter = 0x0;
}
return ch.port;
- };
- PSG49.prototype.step_envelope = function () {
- var step = this.clock.step;
- var ev = this.envelope;
+ }
+ step_envelope() {
+ let step = this.clock.step;
+ let ev = this.envelope;
ev.counter += step;
if (ev.counter >= ev.period) {
ev.matrix[ev.offset][ev.strobe](ev);
ev.counter = 0x0;
}
return (ev.step);
- };
- PSG49.prototype.step_noise = function () {
- var ch = this.channels[3];
- var step = this.clock.step;
- var port = ch.port;
- var period = (ch.period == 0) ? 1 : ch.period;
+ }
+ step_noise() {
+ let ch = this.channels[3];
+ let step = this.clock.step;
+ let port = ch.port;
+ let period = (ch.period == 0) ? 1 : ch.period;
ch.counter += step;
if (ch.counter >= period) {
port ^= (((port & 1) ^ ((port >> 3) & 1)) << 17);
@@ -534,17 +509,17 @@ var PSG49 = /** @class */ (function () {
ch.counter = 0x0;
}
return ch.port & 1;
- };
- PSG49.prototype.step_mixer = function () {
- var port = 0x0;
- var output = [0.0, 0.0];
- var index = 0x0;
- var ch = this.channels;
- var noise = this.step_noise();
- var step = this.step_envelope();
- for (var i = 0; i < 3; i++) {
- var volume = ch[i].volume;
- var pan = ch[i].pan;
+ }
+ step_mixer() {
+ let port = 0x0;
+ let output = [0.0, 0.0];
+ let index = 0x0;
+ let ch = this.channels;
+ let noise = this.step_noise();
+ let step = this.step_envelope();
+ for (let i = 0; i < 3; i++) {
+ let volume = ch[i].volume;
+ let pan = ch[i].pan;
port = this.step_tone(i) | ch[i].tone;
port &= noise | ch[i].noise;
// todo: add dac volume table
@@ -569,22 +544,22 @@ var PSG49 = /** @class */ (function () {
output[1] += port * (pan);
}
return output;
- };
- PSG49.prototype.step = function () {
- var output = [];
- var clockStep = 0;
- var intStep = 0;
- var i = 0x0;
- var clock = this.clock;
- var driver = this.driver;
- var fir = this.fir;
- var oversample = this.oversample;
- var interpolate = this.interpolate;
- var interrupt = this.interrupt;
- var x = clock.scale;
- var fc = clock.frequency;
- var fd = driver.frequency;
- var fi = interrupt.frequency;
+ }
+ step() {
+ let output = [];
+ let clockStep = 0;
+ let intStep = 0;
+ let i = 0x0;
+ let clock = this.clock;
+ let driver = this.driver;
+ let fir = this.fir;
+ let oversample = this.oversample;
+ let interpolate = this.interpolate;
+ let interrupt = this.interrupt;
+ let x = clock.scale;
+ let fc = clock.frequency;
+ let fd = driver.frequency;
+ let fi = interrupt.frequency;
clockStep = (fc * x) / fd;
clock.step = clockStep / oversample;
intStep = fi / fd;
@@ -592,8 +567,8 @@ var PSG49 = /** @class */ (function () {
interrupt.cycle += intStep;
// do we have clock cycles to process?
// if so process single clock cycle
- var sample_left = [];
- var sample_right = [];
+ let sample_left = [];
+ let sample_right = [];
for (i = 0; i < oversample; i++) {
sample_left[i] = 0x0;
sample_right[i] = 0x0;
@@ -603,7 +578,7 @@ var PSG49 = /** @class */ (function () {
interrupt.routine();
interrupt.cycle = 0;
}
- for (var i_1 = 0; i_1 < oversample; i_1++) {
+ for (let i = 0; i < oversample; i++) {
clock.cycle += clockStep;
if (clock.cycle > 1) {
clock.cycle--;
@@ -612,12 +587,11 @@ var PSG49 = /** @class */ (function () {
interpolate[0].step(output[0]);
interpolate[1].step(output[1]);
}
- sample_left[i_1] = interpolate[0].cubic(0.5);
- sample_right[i_1] = interpolate[1].cubic(0.5);
+ sample_left[i] = interpolate[0].cubic(0.5);
+ sample_right[i] = interpolate[1].cubic(0.5);
}
output[0] = fir[0].step(sample_left);
output[1] = fir[1].step(sample_right);
return output;
- };
- return PSG49;
-}());
+ }
+}