1 files changed, 137 insertions, 0 deletions
diff --git a/opl/opl.h b/opl/opl.h
new file mode 100644
index 00000000..04d3cf27
--- /dev/null
+++ b/opl/opl.h
@@ -0,0 +1,137 @@
+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// Copyright(C) 2009 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.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+//
+// DESCRIPTION:
+//     OPL interface.
+//
+//-----------------------------------------------------------------------------
+
+
+#ifndef OPL_OPL_H
+#define OPL_OPL_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
+
+//
+// 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 milliseconds
+// have elapsed, the callback will be invoked.
+
+void OPL_SetCallback(unsigned int ms, opl_callback_t callback, void *data);
+
+// 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 milliseconds have elapsed.
+
+void OPL_Delay(unsigned int ms);
+
+// Pause the OPL callbacks.
+
+void OPL_SetPaused(int paused);
+
+#endif
+