1 /* ScummVM - Graphic Adventure Engine
3 * ScummVM is the legal property of its developers, whose names
4 * are too numerous to list here. Please refer to the COPYRIGHT
5 * file distributed with this source distribution.
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
28 #include "common/scummsys.h"
29 #include "common/str.h"
39 kFlagDualOpl2
= (1 << 1),
44 * OPL type to emulate.
52 typedef int8 DriverId
;
53 struct EmulatorDescription
{
55 const char *description
;
57 DriverId id
; // A unique ID for each driver
58 uint32 flags
; // Capabilities of this driver
62 * Get a list of all available OPL emulators.
63 * @return list of all available OPL emulators, terminated by a zero entry
65 static const EmulatorDescription
*getAvailable() { return _drivers
; }
68 * Returns the driver id of a given name.
70 static DriverId
parse(const Common::String
&name
);
73 * Detects a driver for the specific type.
75 static DriverId
detect(OplType type
);
78 * Creates the specific driver with a specific type setup.
80 static OPL
*create(DriverId driver
, OplType type
);
83 * Wrapper to easily init an OPL chip, without specifing an emulator.
84 * By default it will try to initialize an OPL2 emulator, thus an AdLib card.
86 static OPL
*create(OplType type
= kOpl2
) { return create(detect(type
), type
); }
89 static const EmulatorDescription _drivers
[];
94 // TODO: This is part of a temporary HACK to allow only 1 instance
95 static bool _hasInstance
;
97 OPL() { assert(!_hasInstance
); _hasInstance
= true; }
98 virtual ~OPL() { _hasInstance
= false; }
101 * Initializes the OPL emulator.
103 * @param rate output sample rate
104 * @return true on success, false on failure
106 virtual bool init(int rate
) = 0;
109 * Reinitializes the OPL emulator
111 virtual void reset() = 0;
114 * Writes a byte to the given I/O port.
116 * @param a port address
117 * @param v value, which will be written
119 virtual void write(int a
, int v
) = 0;
122 * Reads a byte from the given I/O port.
124 * @param a port address
127 virtual byte
read(int a
) = 0;
130 * Function to directly write to a specific OPL register.
131 * This writes to *both* chips for a Dual OPL2.
133 * @param r hardware register number to write to
134 * @param v value, which will be written
136 virtual void writeReg(int r
, int v
) = 0;
139 * Read up to 'length' samples.
141 * Data will be in native endianess, 16 bit per sample, signed.
142 * For stereo OPL, buffer will be filled with interleaved
143 * left and right channel samples, starting with a left sample.
144 * Furthermore, the samples in the left and right are summed up.
145 * So if you request 4 samples from a stereo OPL, you will get
146 * a total of two left channel and two right channel samples.
148 virtual void readBuffer(int16
*buffer
, int length
) = 0;
151 * Returns whether the setup OPL mode is stereo or not
153 virtual bool isStereo() const = 0;
156 } // end of namespace OPL
159 // !You should not write any new code using the legacy API!
160 typedef OPL::OPL FM_OPL
;
162 void OPLDestroy(FM_OPL
*OPL
);
164 void OPLResetChip(FM_OPL
*OPL
);
165 void OPLWrite(FM_OPL
*OPL
, int a
, int v
);
166 unsigned char OPLRead(FM_OPL
*OPL
, int a
);
167 void OPLWriteReg(FM_OPL
*OPL
, int r
, int v
);
168 void YM3812UpdateOne(FM_OPL
*OPL
, int16
*buffer
, int length
);
171 * Legacy factory to create an AdLib (OPL2) chip.
173 * !You should not write any new code using the legacy API!
175 FM_OPL
*makeAdlibOPL(int rate
);