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audio/cms.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef AUDIO_CMS_H
+#define AUDIO_CMS_H
+
+#include "audio/chip.h"
+
+namespace CMS {
+
+class CMS;
+
+class Config {
+public:
+	/**
+	 * Creates a CMS driver.
+	 */
+	static CMS *create();
+};
+
+class CMS : virtual public Audio::Chip {
+private:
+	static bool _hasInstance;
+
+public:
+	// The default number of timer callbacks per second.
+	static const int DEFAULT_CALLBACK_FREQUENCY = 250;
+
+	CMS();
+	virtual ~CMS();
+
+	/**
+	 * Initializes the CMS emulator.
+	 *
+	 * @return		true on success, false on failure
+	 */
+	virtual bool init() = 0;
+
+	/**
+	 * Reinitializes the CMS emulator
+	 */
+	virtual void reset() = 0;
+
+	/**
+	 * Writes a byte to the given I/O port. CMS responds to 2 sets of 2 ports:
+	 * 0x220/0x222 - value for the 1st/2nd chip (channels 0-5/6-B)
+	 * 0x221/0x223 - register for the 1st/2nd chip
+	 *
+	 * @param a		port address
+	 * @param v		value, which will be written
+	 */
+	virtual void write(int a, int v) = 0;
+
+	/**
+	 * Function to directly write to a specific CMS register. We allow writing
+	 * to secondary CMS chip registers by using register values >= 0x100.
+	 *
+	 * @param r		hardware register number to write to
+	 * @param v		value, which will be written
+	 */
+	virtual void writeReg(int r, int v) = 0;
+
+	using Audio::Chip::start;
+	void start(TimerCallback *callback) { start(callback, DEFAULT_CALLBACK_FREQUENCY); }
+};
+
+} // End of namespace CMS
+
+#endif