139 lines
3.4 KiB
D
139 lines
3.4 KiB
D
/+
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+ device/speaker.d
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+
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+ Copyright: 2007 Gerald Stocker
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+
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+ This file is part of Twoapple.
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+
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+ Twoapple is free software; you can redistribute it and/or modify
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+ it under the terms of the GNU General Public License as published by
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+ the Free Software Foundation; either version 2 of the License, or
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+ (at your option) any later version.
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+
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+ Twoapple is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ GNU General Public License for more details.
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+
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+ You should have received a copy of the GNU General Public License
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+ along with Twoapple; if not, write to the Free Software
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+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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+/
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module device.speaker;
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import std.c.string;
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import device.base;
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import memory;
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import timer;
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class Speaker
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{
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bool muted;
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Timer.Cycle cycle;
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int sampleTicks;
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ushort sample;
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uint lastToggleTick;
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bool toggled;
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short[] mainBuffer;
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short[] extraBuffer;
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uint mainIndex, extraIndex;
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this()
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{
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sample = 0x8000;
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mainBuffer.length = 8192;
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}
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void setTiming(uint hertz, int sampleFreq, Timer.Cycle deviceCycle)
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{
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extraBuffer.length = sampleTicks = (hertz / sampleFreq);
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cycle = deviceCycle;
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}
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mixin(InitSwitches("", [
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mixin(MakeSwitch([0xC030], "R0W", "toggleSpeaker"))
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]));
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uint processExtraBuffer(uint elapsed)
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{
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uint newElapsed = elapsed;
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if (extraIndex != 0)
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{
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for (; extraIndex < extraBuffer.length; ++extraIndex)
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{
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if (newElapsed == 0) break;
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extraBuffer[extraIndex] = sample;
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--newElapsed;
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}
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if (extraIndex == extraBuffer.length)
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{
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extraIndex = 0;
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long sampleMean = 0;
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for (uint i = 0; i < extraBuffer.length; ++i)
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sampleMean += cast(long)extraBuffer[i];
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sampleMean /= cast(long)extraBuffer.length;
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if (mainIndex < (mainBuffer.length - 1))
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{
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mainBuffer[mainIndex++] =
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(muted ? 0 : cast(short)sampleMean);
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}
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}
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}
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return newElapsed;
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}
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void updateExtraBuffer(uint extraTicks)
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{
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if (extraTicks == 0) return;
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for (extraIndex = 0; extraIndex < extraTicks; ++extraIndex)
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{
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extraBuffer[extraIndex] =
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(muted ? 0 : sample);
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}
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}
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void update()
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{
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uint elapsedSinceToggle = cycle.currentVal() - lastToggleTick;
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lastToggleTick = cycle.currentVal();
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elapsedSinceToggle = processExtraBuffer(elapsedSinceToggle);
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uint samples = elapsedSinceToggle / sampleTicks;
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uint extraTicks = elapsedSinceToggle % sampleTicks;
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// update main buffer
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for (; mainIndex < (mainBuffer.length - 1); ++mainIndex)
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{
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if (samples == 0) break;
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mainBuffer[mainIndex] =
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(muted ? 0 : sample);
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--samples;
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}
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updateExtraBuffer(extraTicks);
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}
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void toggleSpeaker()
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{
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toggled = true;
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update();
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sample = ~sample;
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}
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void clearBuffer()
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{
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mainIndex = 0;
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lastToggleTick = 0;
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toggled = false;
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}
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}
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