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opl.h
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opl.h
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#ifndef OPL_H
#define OPL_H
#include "opl_bank.h"
#define OPL_BASE 0x388
#define NUM_OPL_CHANNELS 9
#define NUM_OPL_MUSIC_CHANNELS 8
#define OPL_SFX_CHANNEL 8
static const opl_channel_offsets[NUM_OPL_CHANNELS] = {
0x0, 0x1, 0x2, 0x8, 0x9, 0xa, 0x10, 0x11, 0x12
};
static volatile uint8_t opl_register_states[256] = { 0 };
#if defined(INLINE_ASM)
void opl_write_asm(uint8_t reg, uint8_t v);
#pragma aux opl_write_asm = \
"mov dx, 388h" \
"out dx, al" \
"mov cx, 6" \
"wait_index:" \
"in al, dx" \
"loop wait_index" \
"inc dx" \
"mov al, bl" \
"out dx, al" \
"mov cx, 35" \
"wait_data:" \
"in al, dx" \
"loop wait_data" \
modify [al bl cx dx] \
parm [al] [bl];
static inline void opl_write(uint8_t reg, uint8_t v) {
opl_register_states[reg] = v;
opl_write_asm(reg, v);
}
static inline void opl_write_fast(uint8_t reg, uint8_t v) {
if (opl_register_states[reg] == v)
return;
opl_register_states[reg] = v;
opl_write_asm(reg, v);
}
#else
static inline void opl_wait_index() {
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
}
static inline void opl_wait_data() {
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE); inp(OPL_BASE);
}
static inline void opl_write(uint8_t reg, uint8_t v) {
opl_register_states[reg] = v;
outp(OPL_BASE, reg);
opl_wait_index();
outp(OPL_BASE + 1, v);
opl_wait_data();
#if 0
if (opl == 3) {
outp(OPL_BASE + 2, reg);
opl_wait_index();
outp(OPL_BASE + 2 + 1, v);
opl_wait_data();
}
#endif
}
static inline void opl_write_fast(uint8_t reg, uint8_t v) {
if (opl_register_states[reg] == v)
return;
opl_register_states[reg] = v;
outp(OPL_BASE, reg);
opl_wait_index();
outp(OPL_BASE + 1, v);
opl_wait_data();
}
#endif
static inline void opl_reset() {
uint8_t i;
if (!opl)
return;
for (i = 0x01; i <= 0xf5; i++) {
opl_write(i, 0);
}
}
static inline void opl_init() {
uint8_t val1, val2;
// Reset timer 1 and 2
opl_write(0x4, 0x60);
// Reset IRQ
opl_write(0x4, 0x80);
// Read status
val1 = inp(OPL_BASE);
// Set timer 1 to 0xff
opl_write(0x2, 0xff);
// Start timer 1
opl_write(0x4, 0x21);
// Delay for more than 80us, pick 10ms
delay(10);
// Read status
val2 = inp(OPL_BASE);
// Reset timer 1 and 2
opl_write(0x4, 0x60);
// Reset IRQ
opl_write(0x4, 0x80);
if ((val1 & 0xe0) != 0x00 || (val2 & 0xe0) != 0xc0) {
return;
}
val1 = inp(OPL_BASE);
if ((val1 & 0x06) == 0x00) {
opl = 3;
} else {
opl = 2;
}
opl_reset();
opl_write(0x01, 0x20);
opl_write(0x08, 0x40);
opl_write(0xbd, 0x80 | 0x40);
}
static inline void opl_done() {
if (!opl)
return;
opl_reset();
opl = 0;
}
static inline void opl_stop(uint8_t channel) {
uint8_t reg;
if (!opl)
return;
reg = 0xb0 + channel;
opl_write(reg, opl_register_states[reg] & ~0x20); // Voice off
}
static const uint16_t opl_freq_table[12] = {
342, 363, 385, 408, 432, 458, 485, 514, 544, 577, 611, 647
};
static const uint8_t opl_attenuation_table[128] = {
0x3F, 0x38, 0x30, 0x2B, 0x28, 0x25, 0x23, 0x21,
0x20, 0x1E, 0x1D, 0x1C, 0x1B, 0x1A, 0x19, 0x18,
0x17, 0x17, 0x16, 0x16, 0x15, 0x14, 0x14, 0x13,
0x13, 0x12, 0x12, 0x11, 0x11, 0x11, 0x10, 0x10,
0x0F, 0x0F, 0x0F, 0x0E, 0x0E, 0x0E, 0x0D, 0x0D,
0x0D, 0x0D, 0x0C, 0x0C, 0x0C, 0x0C, 0x0B, 0x0B,
0x0B, 0x0B, 0x0A, 0x0A, 0x0A, 0x0A, 0x09, 0x09,
0x09, 0x09, 0x09, 0x08, 0x08, 0x08, 0x08, 0x08,
0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x06, 0x06,
0x06, 0x06, 0x06, 0x06, 0x05, 0x05, 0x05, 0x05,
0x05, 0x05, 0x05, 0x04, 0x04, 0x04, 0x04, 0x04,
0x04, 0x04, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
0x03, 0x03, 0x03, 0x02, 0x02, 0x02, 0x02, 0x02,
0x02, 0x02, 0x02, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static inline void opl_play(uint8_t channel, uint8_t program, uint8_t note, uint8_t velocity) {
aw_assert(channel < NUM_OPL_CHANNELS && program < 128 && note < 128 &&
velocity < 128);
if (!opl)
return;
{
const uint8_t* inst_data = opl_bank[program];
uint8_t ch_offset = opl_channel_offsets[channel];
opl_write_fast(0x20 + ch_offset, inst_data[0]);
opl_write_fast(0x23 + ch_offset, inst_data[1]);
{
uint8_t attenuation0, attenuation1;
uint8_t attenuation = opl_attenuation_table[velocity];
if (inst_data[10] & 1) { // If AM
attenuation0 = (inst_data[2] & 0x3f) + attenuation;
if (attenuation0 > 0x3f)
attenuation0 = 0x3f;
opl_write_fast(0x40 + ch_offset, attenuation0 | (inst_data[2] & 0xc0));
} else {
opl_write_fast(0x40 + ch_offset, inst_data[2]);
}
attenuation1 = (inst_data[3] & 0x3f) + attenuation;
if (attenuation1 > 0x3f)
attenuation1 = 0x3f;
opl_write_fast(0x43 + ch_offset, attenuation1 | (inst_data[3] & 0xc0));
}
opl_write_fast(0x60 + ch_offset, inst_data[4]);
opl_write_fast(0x63 + ch_offset, inst_data[5]);
opl_write_fast(0x80 + ch_offset, inst_data[6]);
opl_write_fast(0x83 + ch_offset, inst_data[7]);
opl_write_fast(0xe0 + ch_offset, inst_data[8]);
opl_write_fast(0xe3 + ch_offset, inst_data[9]);
opl_write_fast(0xc0 + channel, inst_data[10]);
}
{
uint8_t octave = 0;
uint16_t f;
while (note >= 12) {
note -= 12;
octave++;
}
f = opl_freq_table[note];
// Set voice frequency's LSB
opl_write_fast(0xa0 + channel, f & 0xff);
// Turn the voice on; set the octave and freq MSB
opl_write(0xb0 + channel, 0x20 | (octave << 2) | (f >> 8));
}
}
static inline void opl_warmup() {
uint8_t i;
for (i = 0; i < NUM_OPL_CHANNELS; ++i) {
opl_play(i, 122, 127, 0);
}
for (i = 0; i < NUM_OPL_CHANNELS; ++i) {
opl_stop(i);
}
}
#endif