scummvm/audio/cms.h

88 lines
2.2 KiB
C++

/* 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