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//
// Copyright(C) 2005-2014 Simon Howard
//
// 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 2
// 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.
//
// DESCRIPTION:
// OPL interface.
//
#ifndef OPL_OPL_H
#define OPL_OPL_H
#include <inttypes.h>
typedef void (*opl_callback_t)(void *data);
typedef enum
{
OPL_REGISTER_PORT = 0,
OPL_DATA_PORT = 1
} opl_port_t;
#define OPL_NUM_OPERATORS 21
#define OPL_NUM_VOICES 9
#define OPL_REG_WAVEFORM_ENABLE 0x01
#define OPL_REG_TIMER1 0x02
#define OPL_REG_TIMER2 0x03
#define OPL_REG_TIMER_CTRL 0x04
#define OPL_REG_FM_MODE 0x08
// Operator registers (21 of each):
#define OPL_REGS_TREMOLO 0x20
#define OPL_REGS_LEVEL 0x40
#define OPL_REGS_ATTACK 0x60
#define OPL_REGS_SUSTAIN 0x80
#define OPL_REGS_WAVEFORM 0xE0
// Voice registers (9 of each):
#define OPL_REGS_FREQ_1 0xA0
#define OPL_REGS_FREQ_2 0xB0
#define OPL_REGS_FEEDBACK 0xC0
// Times
#define OPL_SECOND ((uint64_t) 1000 * 1000)
#define OPL_MS ((uint64_t) 1000)
#define OPL_US ((uint64_t) 1)
//
// Low-level functions.
//
// Initialize the OPL subsystem.
int OPL_Init(unsigned int port_base);
// Shut down the OPL subsystem.
void OPL_Shutdown(void);
// Set the sample rate used for software emulation.
void OPL_SetSampleRate(unsigned int rate);
// Write to one of the OPL I/O ports:
void OPL_WritePort(opl_port_t port, unsigned int value);
// Read from one of the OPL I/O ports:
unsigned int OPL_ReadPort(opl_port_t port);
//
// Higher-level functions.
//
// Read the cuurrent status byte of the OPL chip.
unsigned int OPL_ReadStatus(void);
// Write to an OPL register.
void OPL_WriteRegister(int reg, int value);
// Perform a detection sequence to determine that an
// OPL chip is present.
int OPL_Detect(void);
// Initialize all registers, performed on startup.
void OPL_InitRegisters(void);
//
// Timer callback functions.
//
// Set a timer callback. After the specified number of microseconds
// have elapsed, the callback will be invoked.
void OPL_SetCallback(unsigned int us, opl_callback_t callback, void *data);
// Adjust callback times by the specified factor. For example, a value of
// 0.5 will halve all remaining times.
void OPL_AdjustCallbacks(float factor);
// Clear all OPL callbacks that have been set.
void OPL_ClearCallbacks(void);
// Begin critical section, during which, OPL callbacks will not be
// invoked.
void OPL_Lock(void);
// End critical section.
void OPL_Unlock(void);
// Block until the specified number of microseconds have elapsed.
void OPL_Delay(unsigned int us);
// Pause the OPL callbacks.
void OPL_SetPaused(int paused);
#endif
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