PIT ports and modes
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9
PIT.js
9
PIT.js
@ -15,6 +15,9 @@ function PIT(PC, ah, bh) {
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}
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}
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this.speaker_data_on = 0;
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this.speaker_data_on = 0;
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this.set_irq = ah;
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this.set_irq = ah;
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// Ports:
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// 0x40: Channel 0 data port
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// 0x61: Control
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PC.register_ioport_write(0x40, 4, 1, this.ioport_write.bind(this));
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PC.register_ioport_write(0x40, 4, 1, this.ioport_write.bind(this));
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PC.register_ioport_read(0x40, 3, 1, this.ioport_read.bind(this));
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PC.register_ioport_read(0x40, 3, 1, this.ioport_read.bind(this));
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PC.register_ioport_read(0x61, 1, 1, this.speaker_ioport_read.bind(this));
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PC.register_ioport_read(0x61, 1, 1, this.speaker_ioport_read.bind(this));
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@ -58,22 +61,28 @@ IRQCH.prototype.pit_get_out = function() {
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d = this.get_time() - this.count_load_time;
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d = this.get_time() - this.count_load_time;
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switch (this.mode) {
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switch (this.mode) {
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default:
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default:
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// Interrupt on terminal count
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case 0:
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case 0:
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eh = (d >= this.count) >> 0;
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eh = (d >= this.count) >> 0;
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break;
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break;
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// One shot
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case 1:
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case 1:
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eh = (d < this.count) >> 0;
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eh = (d < this.count) >> 0;
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break;
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break;
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// Frequency divider
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case 2:
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case 2:
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if ((d % this.count) == 0 && d != 0)
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if ((d % this.count) == 0 && d != 0)
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eh = 1;
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eh = 1;
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else
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else
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eh = 0;
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eh = 0;
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break;
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break;
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// Square wave
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case 3:
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case 3:
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eh = ((d % this.count) < (this.count >> 1)) >> 0;
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eh = ((d % this.count) < (this.count >> 1)) >> 0;
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break;
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break;
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// SW strobe
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case 4:
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case 4:
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// HW strobe
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case 5:
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case 5:
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eh = (d == this.count) >> 0;
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eh = (d == this.count) >> 0;
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break;
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break;
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