206 lines
4.0 KiB
JavaScript
206 lines
4.0 KiB
JavaScript
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// var h = preact.h;
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function calc_sr(osc) {
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// iigs is ~7.14Mhz / 8. Mirage is 8Mhz / 8
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return (28.63636*1000*1000/32) / (osc + 2);
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}
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function calc_shift(res,ws) {
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return res + 9 - ws;
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}
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function log2(x) {
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var y = Math.log2(x);
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return (y >> 0) === y ? y : false;
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}
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function Oscillators(props) {
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var options = []
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for (var i = 1; i < 33; ++i) {
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options.push(<option value={i} key={i}>{i}</option>);
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}
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return <select value={props.value} onChange={props.onChange}>{options}</select>;
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}
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function WaveSize(props) {
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var options = []
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for (var i = 8; i < 16; ++i) {
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var ext = 1 << i;
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var int = i - 8;
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options.push(<option value={int} key={int}>{ext}</option>);
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}
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return <select value={props.value} onChange={props.onChange}>{options}</select>;
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}
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function Resolution(props) {
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var options = []
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for (var i = 0; i < 8; ++i) {
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options.push(<option value={i} key={i}>{i}</option>);
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}
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return <select value={props.value} onChange={props.onChange}>{options}</select>;
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}
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function Frequency(props) {
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/* number, min, max are not as strict as they ought to be */
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return <input type="number" min="0" max="65535" value={props.value} onChange={props.onChange} />;
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}
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function nmultiply(x) {
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if (x == 0) return 0;
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if (x == 1) return <i>n</i>;
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return <span>{x} * <i>n</i></span>;
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// return paren ? <span>({x} * <i>n</i>)</span> : <span>{x} * <i>n</i></span>;
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}
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function SampleDisplay(props) {
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var { shift, freq } = props;
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var freq2 = log2(freq);
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var fspan = <span title="Frequency">{freq}</span>;
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var rv = [];
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rv.push(
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<div>
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Sample<sub>n</sub> = RAM[ ({fspan} * <i>n</i>) >> {shift} ]
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</div>
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);
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rv.push(
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<div>
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Sample<sub>n</sub> = RAM[ ({fspan} * <i>n</i>) / {1 << shift} ]
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</div>
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);
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if (freq2) {
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if (freq2 >= shift) {
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rv.push(
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<div>
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Sample<sub>n</sub> = RAM[ { nmultiply(freq / ( 1 << shift)) } ]
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</div>
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);
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} else {
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rv.push(
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<div>
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Sample<sub>n</sub> = RAM[ { nmultiply(freq >> freq2) } >> {shift - freq2} ]
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</div>
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);
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rv.push(
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<div>
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Sample<sub>n</sub> = RAM[ { nmultiply(freq >> freq2) } / { 1 << (shift - freq2) } ]
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</div>
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);
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}
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}
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return rv;
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}
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// oscillators generate addresses, not samples.
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// accumulator is 24-bit.
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// frequency is 16-bit.
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// accumulator n = freq * n
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// sample n = memory[(freq * n) >> res. shift]
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export class Application extends preact.Component {
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constructor(props) {
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super(props);
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this._oscChange = this.oscChange.bind(this);
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this._waveChange = this.waveChange.bind(this);
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this._resChange = this.resChange.bind(this);
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this._freqChange = this.freqChange.bind(this);
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this.state = { osc: 32, wave: 0, res: 0, freq: 512 };
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}
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oscChange(e) {
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e.preventDefault();
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var v = +e.target.value || 0;
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this.setState( { osc: v } );
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}
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waveChange(e) {
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e.preventDefault();
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var v = +e.target.value || 0;
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this.setState( { wave: v } );
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}
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resChange(e) {
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e.preventDefault();
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var v = +e.target.value || 0;
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this.setState( { res: v } );
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}
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freqChange(e) {
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e.preventDefault();
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var v = +e.target.value >> 0;
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if (v < 0) v = 0;
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if (v > 65535) v = 65535;
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this.setState( { freq: v } );
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}
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form() {
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var { osc, wave, res, freq } = this.state;
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return (
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<div id="form">
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<div>
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<label>Oscillators</label> <Oscillators value={osc} onChange={this._oscChange} />
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</div>
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<div>
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<label>Wave Size</label> <WaveSize value={wave} onChange={this._waveChange} />
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</div>
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<div>
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<label>Resolution</label> <Resolution value={res} onChange={this._resChange} />
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</div>
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<div>
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<label>Frequency</label> <Frequency value={freq} onChange={this._freqChange} />
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</div>
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</div>
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);
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}
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render() {
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var { osc, wave, res, freq } = this.state;
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var shift = calc_shift(res, wave);
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return (
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<div>
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{ this.form() }
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<div>
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Scan Rate: { (calc_sr(osc) / 1000 ).toFixed(2) } kHz
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</div>
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<SampleDisplay freq={freq} shift={shift} />
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</div>
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);
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}
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}
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/*
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window.addEventListener('load', function(){
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preact.render(
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<Application />,
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document.getElementById('application')
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);
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});
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*/
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