//
//  Nuked OPL3 emulator.
//  Thanks:
//      MAME Development Team(Jarek Burczynski, Tatsuyuki Satoh):
//          Feedback and Rhythm part calculation information.
//      forums.submarine.org.uk(carbon14, opl3):
//          Tremolo and phase generator calculation information.
//      OPLx decapsulated(Matthew Gambrell, Olli Niemitalo):
//          OPL2 ROMs.
//
// version: 1.7.4
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dosbox/nukedopl.h"

#define RSM_FRAC    10

// Channel types

enum {
	ch_2op = 0,
	ch_4op = 1,
	ch_4op2 = 2,
	ch_drum = 3
};

// Envelope key types

enum {
	egk_norm = 0x01,
	egk_drum = 0x02
};


//
// logsin table
//

static const Bit16u logsinrom[256] = {
	0x859, 0x6c3, 0x607, 0x58b, 0x52e, 0x4e4, 0x4a6, 0x471,
	0x443, 0x41a, 0x3f5, 0x3d3, 0x3b5, 0x398, 0x37e, 0x365,
	0x34e, 0x339, 0x324, 0x311, 0x2ff, 0x2ed, 0x2dc, 0x2cd,
	0x2bd, 0x2af, 0x2a0, 0x293, 0x286, 0x279, 0x26d, 0x261,
	0x256, 0x24b, 0x240, 0x236, 0x22c, 0x222, 0x218, 0x20f,
	0x206, 0x1fd, 0x1f5, 0x1ec, 0x1e4, 0x1dc, 0x1d4, 0x1cd,
	0x1c5, 0x1be, 0x1b7, 0x1b0, 0x1a9, 0x1a2, 0x19b, 0x195,
	0x18f, 0x188, 0x182, 0x17c, 0x177, 0x171, 0x16b, 0x166,
	0x160, 0x15b, 0x155, 0x150, 0x14b, 0x146, 0x141, 0x13c,
	0x137, 0x133, 0x12e, 0x129, 0x125, 0x121, 0x11c, 0x118,
	0x114, 0x10f, 0x10b, 0x107, 0x103, 0x0ff, 0x0fb, 0x0f8,
	0x0f4, 0x0f0, 0x0ec, 0x0e9, 0x0e5, 0x0e2, 0x0de, 0x0db,
	0x0d7, 0x0d4, 0x0d1, 0x0cd, 0x0ca, 0x0c7, 0x0c4, 0x0c1,
	0x0be, 0x0bb, 0x0b8, 0x0b5, 0x0b2, 0x0af, 0x0ac, 0x0a9,
	0x0a7, 0x0a4, 0x0a1, 0x09f, 0x09c, 0x099, 0x097, 0x094,
	0x092, 0x08f, 0x08d, 0x08a, 0x088, 0x086, 0x083, 0x081,
	0x07f, 0x07d, 0x07a, 0x078, 0x076, 0x074, 0x072, 0x070,
	0x06e, 0x06c, 0x06a, 0x068, 0x066, 0x064, 0x062, 0x060,
	0x05e, 0x05c, 0x05b, 0x059, 0x057, 0x055, 0x053, 0x052,
	0x050, 0x04e, 0x04d, 0x04b, 0x04a, 0x048, 0x046, 0x045,
	0x043, 0x042, 0x040, 0x03f, 0x03e, 0x03c, 0x03b, 0x039,
	0x038, 0x037, 0x035, 0x034, 0x033, 0x031, 0x030, 0x02f,
	0x02e, 0x02d, 0x02b, 0x02a, 0x029, 0x028, 0x027, 0x026,
	0x025, 0x024, 0x023, 0x022, 0x021, 0x020, 0x01f, 0x01e,
	0x01d, 0x01c, 0x01b, 0x01a, 0x019, 0x018, 0x017, 0x017,
	0x016, 0x015, 0x014, 0x014, 0x013, 0x012, 0x011, 0x011,
	0x010, 0x00f, 0x00f, 0x00e, 0x00d, 0x00d, 0x00c, 0x00c,
	0x00b, 0x00a, 0x00a, 0x009, 0x009, 0x008, 0x008, 0x007,
	0x007, 0x007, 0x006, 0x006, 0x005, 0x005, 0x005, 0x004,
	0x004, 0x004, 0x003, 0x003, 0x003, 0x002, 0x002, 0x002,
	0x002, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001,
	0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000
};

//
// exp table
//

static const Bit16u exprom[256] = {
	0x000, 0x003, 0x006, 0x008, 0x00b, 0x00e, 0x011, 0x014,
	0x016, 0x019, 0x01c, 0x01f, 0x022, 0x025, 0x028, 0x02a,
	0x02d, 0x030, 0x033, 0x036, 0x039, 0x03c, 0x03f, 0x042,
	0x045, 0x048, 0x04b, 0x04e, 0x051, 0x054, 0x057, 0x05a,
	0x05d, 0x060, 0x063, 0x066, 0x069, 0x06c, 0x06f, 0x072,
	0x075, 0x078, 0x07b, 0x07e, 0x082, 0x085, 0x088, 0x08b,
	0x08e, 0x091, 0x094, 0x098, 0x09b, 0x09e, 0x0a1, 0x0a4,
	0x0a8, 0x0ab, 0x0ae, 0x0b1, 0x0b5, 0x0b8, 0x0bb, 0x0be,
	0x0c2, 0x0c5, 0x0c8, 0x0cc, 0x0cf, 0x0d2, 0x0d6, 0x0d9,
	0x0dc, 0x0e0, 0x0e3, 0x0e7, 0x0ea, 0x0ed, 0x0f1, 0x0f4,
	0x0f8, 0x0fb, 0x0ff, 0x102, 0x106, 0x109, 0x10c, 0x110,
	0x114, 0x117, 0x11b, 0x11e, 0x122, 0x125, 0x129, 0x12c,
	0x130, 0x134, 0x137, 0x13b, 0x13e, 0x142, 0x146, 0x149,
	0x14d, 0x151, 0x154, 0x158, 0x15c, 0x160, 0x163, 0x167,
	0x16b, 0x16f, 0x172, 0x176, 0x17a, 0x17e, 0x181, 0x185,
	0x189, 0x18d, 0x191, 0x195, 0x199, 0x19c, 0x1a0, 0x1a4,
	0x1a8, 0x1ac, 0x1b0, 0x1b4, 0x1b8, 0x1bc, 0x1c0, 0x1c4,
	0x1c8, 0x1cc, 0x1d0, 0x1d4, 0x1d8, 0x1dc, 0x1e0, 0x1e4,
	0x1e8, 0x1ec, 0x1f0, 0x1f5, 0x1f9, 0x1fd, 0x201, 0x205,
	0x209, 0x20e, 0x212, 0x216, 0x21a, 0x21e, 0x223, 0x227,
	0x22b, 0x230, 0x234, 0x238, 0x23c, 0x241, 0x245, 0x249,
	0x24e, 0x252, 0x257, 0x25b, 0x25f, 0x264, 0x268, 0x26d,
	0x271, 0x276, 0x27a, 0x27f, 0x283, 0x288, 0x28c, 0x291,
	0x295, 0x29a, 0x29e, 0x2a3, 0x2a8, 0x2ac, 0x2b1, 0x2b5,
	0x2ba, 0x2bf, 0x2c4, 0x2c8, 0x2cd, 0x2d2, 0x2d6, 0x2db,
	0x2e0, 0x2e5, 0x2e9, 0x2ee, 0x2f3, 0x2f8, 0x2fd, 0x302,
	0x306, 0x30b, 0x310, 0x315, 0x31a, 0x31f, 0x324, 0x329,
	0x32e, 0x333, 0x338, 0x33d, 0x342, 0x347, 0x34c, 0x351,
	0x356, 0x35b, 0x360, 0x365, 0x36a, 0x370, 0x375, 0x37a,
	0x37f, 0x384, 0x38a, 0x38f, 0x394, 0x399, 0x39f, 0x3a4,
	0x3a9, 0x3ae, 0x3b4, 0x3b9, 0x3bf, 0x3c4, 0x3c9, 0x3cf,
	0x3d4, 0x3da, 0x3df, 0x3e4, 0x3ea, 0x3ef, 0x3f5, 0x3fa
};

//
// freq mult table multiplied by 2
//
// 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 12, 12, 15, 15
//

static const Bit8u mt[16] = {
	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 20, 24, 24, 30, 30
};

//
// ksl table
//

static const Bit8u kslrom[16] = {
	0, 32, 40, 45, 48, 51, 53, 55, 56, 58, 59, 60, 61, 62, 63, 64
};

static const Bit8u kslshift[4] = {
	8, 1, 2, 0
};

//
// envelope generator constants
//

static const Bit8u eg_incstep[3][4][8] = {
	{
		{0, 0, 0, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 0}
	},
	{
		{0, 1, 0, 1, 0, 1, 0, 1},
		{0, 1, 0, 1, 1, 1, 0, 1},
		{0, 1, 1, 1, 0, 1, 1, 1},
		{0, 1, 1, 1, 1, 1, 1, 1}
	},
	{
		{1, 1, 1, 1, 1, 1, 1, 1},
		{2, 2, 1, 1, 1, 1, 1, 1},
		{2, 2, 1, 1, 2, 2, 1, 1},
		{2, 2, 2, 2, 2, 2, 1, 1}
	}
};

static const Bit8u eg_incdesc[16] = {
	0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2
};

static const Bit8s eg_incsh[16] = {
	0, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, -1, -2
};

//
// address decoding
//

static const Bit8s ad_slot[0x20] = {
	0, 1, 2, 3, 4, 5, -1, -1, 6, 7, 8, 9, 10, 11, -1, -1,
	12, 13, 14, 15, 16, 17, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};

static const Bit8u ch_slot[18] = {
	0, 1, 2, 6, 7, 8, 12, 13, 14, 18, 19, 20, 24, 25, 26, 30, 31, 32
};

//
// Envelope generator
//

typedef Bit16s(*envelope_sinfunc)(Bit16u phase, Bit16u envelope);
typedef void(*envelope_genfunc)(opl3_slot *slott);

static Bit16s OPL3_EnvelopeCalcExp(Bit32u level) {
	if (level > 0x1fff) {
		level = 0x1fff;
	}
	return ((exprom[(level & 0xff) ^ 0xff] | 0x400) << 1) >> (level >> 8);
}

static Bit16s OPL3_EnvelopeCalcSin0(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	Bit16u neg = 0;
	phase &= 0x3ff;
	if (phase & 0x200) {
		neg = ~0;
	}
	if (phase & 0x100) {
		out = logsinrom[(phase & 0xff) ^ 0xff];
	} else {
		out = logsinrom[phase & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3)) ^ neg;
}

static Bit16s OPL3_EnvelopeCalcSin1(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	phase &= 0x3ff;
	if (phase & 0x200) {
		out = 0x1000;
	} else if (phase & 0x100) {
		out = logsinrom[(phase & 0xff) ^ 0xff];
	} else {
		out = logsinrom[phase & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3));
}

static Bit16s OPL3_EnvelopeCalcSin2(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	phase &= 0x3ff;
	if (phase & 0x100) {
		out = logsinrom[(phase & 0xff) ^ 0xff];
	} else {
		out = logsinrom[phase & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3));
}

static Bit16s OPL3_EnvelopeCalcSin3(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	phase &= 0x3ff;
	if (phase & 0x100) {
		out = 0x1000;
	} else {
		out = logsinrom[phase & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3));
}

static Bit16s OPL3_EnvelopeCalcSin4(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	Bit16u neg = 0;
	phase &= 0x3ff;
	if ((phase & 0x300) == 0x100) {
		neg = ~0;
	}
	if (phase & 0x200) {
		out = 0x1000;
	} else if (phase & 0x80) {
		out = logsinrom[((phase ^ 0xff) << 1) & 0xff];
	} else {
		out = logsinrom[(phase << 1) & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3)) ^ neg;
}

static Bit16s OPL3_EnvelopeCalcSin5(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	phase &= 0x3ff;
	if (phase & 0x200) {
		out = 0x1000;
	} else if (phase & 0x80) {
		out = logsinrom[((phase ^ 0xff) << 1) & 0xff];
	} else {
		out = logsinrom[(phase << 1) & 0xff];
	}
	return OPL3_EnvelopeCalcExp(out + (envelope << 3));
}

static Bit16s OPL3_EnvelopeCalcSin6(Bit16u phase, Bit16u envelope) {
	Bit16u neg = 0;
	phase &= 0x3ff;
	if (phase & 0x200) {
		neg = ~0;
	}
	return OPL3_EnvelopeCalcExp(envelope << 3) ^ neg;
}

static Bit16s OPL3_EnvelopeCalcSin7(Bit16u phase, Bit16u envelope) {
	Bit16u out = 0;
	Bit16u neg = 0;
	phase &= 0x3ff;
	if (phase & 0x200) {
		neg = ~0;
		phase = (phase & 0x1ff) ^ 0x1ff;
	}
	out = phase << 3;
	return OPL3_EnvelopeCalcExp(out + (envelope << 3)) ^ neg;
}

static const envelope_sinfunc envelope_sin[8] = {
	OPL3_EnvelopeCalcSin0,
	OPL3_EnvelopeCalcSin1,
	OPL3_EnvelopeCalcSin2,
	OPL3_EnvelopeCalcSin3,
	OPL3_EnvelopeCalcSin4,
	OPL3_EnvelopeCalcSin5,
	OPL3_EnvelopeCalcSin6,
	OPL3_EnvelopeCalcSin7
};

static void OPL3_EnvelopeGenOff(opl3_slot *slot);
static void OPL3_EnvelopeGenAttack(opl3_slot *slot);
static void OPL3_EnvelopeGenDecay(opl3_slot *slot);
static void OPL3_EnvelopeGenSustain(opl3_slot *slot);
static void OPL3_EnvelopeGenRelease(opl3_slot *slot);

envelope_genfunc envelope_gen[5] = {
	OPL3_EnvelopeGenOff,
	OPL3_EnvelopeGenAttack,
	OPL3_EnvelopeGenDecay,
	OPL3_EnvelopeGenSustain,
	OPL3_EnvelopeGenRelease
};

enum envelope_gen_num {
	envelope_gen_num_off = 0,
	envelope_gen_num_attack = 1,
	envelope_gen_num_decay = 2,
	envelope_gen_num_sustain = 3,
	envelope_gen_num_release = 4
};

static Bit8u OPL3_EnvelopeCalcRate(opl3_slot *slot, Bit8u reg_rate) {
	Bit8u rate;
	if (reg_rate == 0x00) {
		return 0x00;
	}
	rate = (reg_rate << 2)
		+ (slot->reg_ksr ? slot->channel->ksv : (slot->channel->ksv >> 2));
	if (rate > 0x3c) {
		rate = 0x3c;
	}
	return rate;
}

static void OPL3_EnvelopeUpdateKSL(opl3_slot *slot) {
	Bit16s ksl = (kslrom[slot->channel->f_num >> 6] << 2)
		- ((0x08 - slot->channel->block) << 5);
	if (ksl < 0) {
		ksl = 0;
	}
	slot->eg_ksl = (Bit8u)ksl;
}

static void OPL3_EnvelopeUpdateRate(opl3_slot *slot) {
	switch (slot->eg_gen) {
	case envelope_gen_num_off:
	case envelope_gen_num_attack:slot->eg_rate = OPL3_EnvelopeCalcRate(slot, slot->reg_ar);
		break;
	case envelope_gen_num_decay:slot->eg_rate = OPL3_EnvelopeCalcRate(slot, slot->reg_dr);
		break;
	case envelope_gen_num_sustain:
	case envelope_gen_num_release:slot->eg_rate = OPL3_EnvelopeCalcRate(slot, slot->reg_rr);
		break;
	}
}

static void OPL3_EnvelopeGenOff(opl3_slot *slot) {
	slot->eg_rout = 0x1ff;
}

static void OPL3_EnvelopeGenAttack(opl3_slot *slot) {
	if (slot->eg_rout == 0x00) {
		slot->eg_gen = envelope_gen_num_decay;
		OPL3_EnvelopeUpdateRate(slot);
		return;
	}
	slot->eg_rout += ((~slot->eg_rout) * slot->eg_inc) >> 3;
	if (slot->eg_rout < 0x00) {
		slot->eg_rout = 0x00;
	}
}

static void OPL3_EnvelopeGenDecay(opl3_slot *slot) {
	if (slot->eg_rout >= slot->reg_sl << 4) {
		slot->eg_gen = envelope_gen_num_sustain;
		OPL3_EnvelopeUpdateRate(slot);
		return;
	}
	slot->eg_rout += slot->eg_inc;
}

static void OPL3_EnvelopeGenSustain(opl3_slot *slot) {
	if (!slot->reg_type) {
		OPL3_EnvelopeGenRelease(slot);
	}
}

static void OPL3_EnvelopeGenRelease(opl3_slot *slot) {
	if (slot->eg_rout >= 0x1ff) {
		slot->eg_gen = envelope_gen_num_off;
		slot->eg_rout = 0x1ff;
		OPL3_EnvelopeUpdateRate(slot);
		return;
	}
	slot->eg_rout += slot->eg_inc;
}

static void OPL3_EnvelopeCalc(opl3_slot *slot) {
	Bit8u rate_h, rate_l;
	Bit8u inc = 0;
	rate_h = slot->eg_rate >> 2;
	rate_l = slot->eg_rate & 3;
	if (eg_incsh[rate_h] > 0) {
		if ((slot->chip->timer & ((1 << eg_incsh[rate_h]) - 1)) == 0) {
			inc = eg_incstep[eg_incdesc[rate_h]][rate_l]
			[((slot->chip->timer) >> eg_incsh[rate_h]) & 0x07];
		}
	} else {
		inc = eg_incstep[eg_incdesc[rate_h]][rate_l]
		[slot->chip->timer & 0x07] << (-eg_incsh[rate_h]);
	}
	slot->eg_inc = inc;
	slot->eg_out = slot->eg_rout + (slot->reg_tl << 2)
		+ (slot->eg_ksl >> kslshift[slot->reg_ksl]) + *slot->trem;
	envelope_gen[slot->eg_gen](slot);
}

static void OPL3_EnvelopeKeyOn(opl3_slot *slot, Bit8u type) {
	if (!slot->key) {
		slot->eg_gen = envelope_gen_num_attack;
		OPL3_EnvelopeUpdateRate(slot);
		if ((slot->eg_rate >> 2) == 0x0f) {
			slot->eg_gen = envelope_gen_num_decay;
			OPL3_EnvelopeUpdateRate(slot);
			slot->eg_rout = 0x00;
		}
		slot->pg_phase = 0x00;
	}
	slot->key |= type;
}

static void OPL3_EnvelopeKeyOff(opl3_slot *slot, Bit8u type) {
	if (slot->key) {
		slot->key &= (~type);
		if (!slot->key) {
			slot->eg_gen = envelope_gen_num_release;
			OPL3_EnvelopeUpdateRate(slot);
		}
	}
}

//
// Phase Generator
//

static void OPL3_PhaseGenerate(opl3_slot *slot) {
	Bit16u f_num;
	Bit32u basefreq;

	f_num = slot->channel->f_num;
	if (slot->reg_vib) {
		Bit8s range;
		Bit8u vibpos;

		range = (f_num >> 7) & 7;
		vibpos = slot->chip->vibpos;

		if (!(vibpos & 3)) {
			range = 0;
		} else if (vibpos & 1) {
			range >>= 1;
		}
		range >>= slot->chip->vibshift;

		if (vibpos & 4) {
			range = -range;
		}
		f_num += range;
	}
	basefreq = (f_num << slot->channel->block) >> 1;
	slot->pg_phase += (basefreq * mt[slot->reg_mult]) >> 1;
}

//
// Noise Generator
//

static void OPL3_NoiseGenerate(opl3_chip *chip) {
	if (chip->noise & 0x01) {
		chip->noise ^= 0x800302;
	}
	chip->noise >>= 1;
}

//
// Slot
//

static void OPL3_SlotWrite20(opl3_slot *slot, Bit8u data) {
	if ((data >> 7) & 0x01) {
		slot->trem = &slot->chip->tremolo;
	} else {
		slot->trem = (Bit8u *)&slot->chip->zeromod;
	}
	slot->reg_vib = (data >> 6) & 0x01;
	slot->reg_type = (data >> 5) & 0x01;
	slot->reg_ksr = (data >> 4) & 0x01;
	slot->reg_mult = data & 0x0f;
	OPL3_EnvelopeUpdateRate(slot);
}

static void OPL3_SlotWrite40(opl3_slot *slot, Bit8u data) {
	slot->reg_ksl = (data >> 6) & 0x03;
	slot->reg_tl = data & 0x3f;
	OPL3_EnvelopeUpdateKSL(slot);
}

static void OPL3_SlotWrite60(opl3_slot *slot, Bit8u data) {
	slot->reg_ar = (data >> 4) & 0x0f;
	slot->reg_dr = data & 0x0f;
	OPL3_EnvelopeUpdateRate(slot);
}

static void OPL3_SlotWrite80(opl3_slot *slot, Bit8u data) {
	slot->reg_sl = (data >> 4) & 0x0f;
	if (slot->reg_sl == 0x0f) {
		slot->reg_sl = 0x1f;
	}
	slot->reg_rr = data & 0x0f;
	OPL3_EnvelopeUpdateRate(slot);
}

static void OPL3_SlotWriteE0(opl3_slot *slot, Bit8u data) {
	slot->reg_wf = data & 0x07;
	if (slot->chip->newm == 0x00) {
		slot->reg_wf &= 0x03;
	}
}

static void OPL3_SlotGeneratePhase(opl3_slot *slot, Bit16u phase) {
	slot->out = envelope_sin[slot->reg_wf](phase, slot->eg_out);
}

static void OPL3_SlotGenerate(opl3_slot *slot) {
	OPL3_SlotGeneratePhase(slot, (Bit16u)(slot->pg_phase >> 9) + *slot->mod);
}

static void OPL3_SlotGenerateZM(opl3_slot *slot) {
	OPL3_SlotGeneratePhase(slot, (Bit16u)(slot->pg_phase >> 9));
}

static void OPL3_SlotCalcFB(opl3_slot *slot) {
	if (slot->channel->fb != 0x00) {
		slot->fbmod = (slot->prout + slot->out) >> (0x09 - slot->channel->fb);
	} else {
		slot->fbmod = 0;
	}
	slot->prout = slot->out;
}

//
// Channel
//

static void OPL3_ChannelSetupAlg(opl3_channel *channel);

static void OPL3_ChannelUpdateRhythm(opl3_chip *chip, Bit8u data) {
	opl3_channel *channel6;
	opl3_channel *channel7;
	opl3_channel *channel8;
	Bit8u chnum;

	chip->rhy = data & 0x3f;
	if (chip->rhy & 0x20) {
		channel6 = &chip->channel[6];
		channel7 = &chip->channel[7];
		channel8 = &chip->channel[8];
		channel6->out[0] = &channel6->slots[1]->out;
		channel6->out[1] = &channel6->slots[1]->out;
		channel6->out[2] = &chip->zeromod;
		channel6->out[3] = &chip->zeromod;
		channel7->out[0] = &channel7->slots[0]->out;
		channel7->out[1] = &channel7->slots[0]->out;
		channel7->out[2] = &channel7->slots[1]->out;
		channel7->out[3] = &channel7->slots[1]->out;
		channel8->out[0] = &channel8->slots[0]->out;
		channel8->out[1] = &channel8->slots[0]->out;
		channel8->out[2] = &channel8->slots[1]->out;
		channel8->out[3] = &channel8->slots[1]->out;
		for (chnum = 6; chnum < 9; chnum++) {
			chip->channel[chnum].chtype = ch_drum;
		}
		OPL3_ChannelSetupAlg(channel6);
		//hh
		if (chip->rhy & 0x01) {
			OPL3_EnvelopeKeyOn(channel7->slots[0], egk_drum);
		} else {
			OPL3_EnvelopeKeyOff(channel7->slots[0], egk_drum);
		}
		//tc
		if (chip->rhy & 0x02) {
			OPL3_EnvelopeKeyOn(channel8->slots[1], egk_drum);
		} else {
			OPL3_EnvelopeKeyOff(channel8->slots[1], egk_drum);
		}
		//tom
		if (chip->rhy & 0x04) {
			OPL3_EnvelopeKeyOn(channel8->slots[0], egk_drum);
		} else {
			OPL3_EnvelopeKeyOff(channel8->slots[0], egk_drum);
		}
		//sd
		if (chip->rhy & 0x08) {
			OPL3_EnvelopeKeyOn(channel7->slots[1], egk_drum);
		} else {
			OPL3_EnvelopeKeyOff(channel7->slots[1], egk_drum);
		}
		//bd
		if (chip->rhy & 0x10) {
			OPL3_EnvelopeKeyOn(channel6->slots[0], egk_drum);
			OPL3_EnvelopeKeyOn(channel6->slots[1], egk_drum);
		} else {
			OPL3_EnvelopeKeyOff(channel6->slots[0], egk_drum);
			OPL3_EnvelopeKeyOff(channel6->slots[1], egk_drum);
		}
	} else {
		for (chnum = 6; chnum < 9; chnum++) {
			chip->channel[chnum].chtype = ch_2op;
			OPL3_ChannelSetupAlg(&chip->channel[chnum]);
			OPL3_EnvelopeKeyOff(chip->channel[chnum].slots[0], egk_drum);
			OPL3_EnvelopeKeyOff(chip->channel[chnum].slots[1], egk_drum);
		}
	}
}

static void OPL3_ChannelWriteA0(opl3_channel *channel, Bit8u data) {
	if (channel->chip->newm && channel->chtype == ch_4op2) {
		return;
	}
	channel->f_num = (channel->f_num & 0x300) | data;
	channel->ksv = (channel->block << 1)
		| ((channel->f_num >> (0x09 - channel->chip->nts)) & 0x01);
	OPL3_EnvelopeUpdateKSL(channel->slots[0]);
	OPL3_EnvelopeUpdateKSL(channel->slots[1]);
	OPL3_EnvelopeUpdateRate(channel->slots[0]);
	OPL3_EnvelopeUpdateRate(channel->slots[1]);
	if (channel->chip->newm && channel->chtype == ch_4op) {
		channel->pair->f_num = channel->f_num;
		channel->pair->ksv = channel->ksv;
		OPL3_EnvelopeUpdateKSL(channel->pair->slots[0]);
		OPL3_EnvelopeUpdateKSL(channel->pair->slots[1]);
		OPL3_EnvelopeUpdateRate(channel->pair->slots[0]);
		OPL3_EnvelopeUpdateRate(channel->pair->slots[1]);
	}
}

static void OPL3_ChannelWriteB0(opl3_channel *channel, Bit8u data) {
	if (channel->chip->newm && channel->chtype == ch_4op2) {
		return;
	}
	channel->f_num = (channel->f_num & 0xff) | ((data & 0x03) << 8);
	channel->block = (data >> 2) & 0x07;
	channel->ksv = (channel->block << 1)
		| ((channel->f_num >> (0x09 - channel->chip->nts)) & 0x01);
	OPL3_EnvelopeUpdateKSL(channel->slots[0]);
	OPL3_EnvelopeUpdateKSL(channel->slots[1]);
	OPL3_EnvelopeUpdateRate(channel->slots[0]);
	OPL3_EnvelopeUpdateRate(channel->slots[1]);
	if (channel->chip->newm && channel->chtype == ch_4op) {
		channel->pair->f_num = channel->f_num;
		channel->pair->block = channel->block;
		channel->pair->ksv = channel->ksv;
		OPL3_EnvelopeUpdateKSL(channel->pair->slots[0]);
		OPL3_EnvelopeUpdateKSL(channel->pair->slots[1]);
		OPL3_EnvelopeUpdateRate(channel->pair->slots[0]);
		OPL3_EnvelopeUpdateRate(channel->pair->slots[1]);
	}
}

static void OPL3_ChannelSetupAlg(opl3_channel *channel) {
	if (channel->chtype == ch_drum) {
		switch (channel->alg & 0x01) {
		case 0x00:channel->slots[0]->mod = &channel->slots[0]->fbmod;
			channel->slots[1]->mod = &channel->slots[0]->out;
			break;
		case 0x01:channel->slots[0]->mod = &channel->slots[0]->fbmod;
			channel->slots[1]->mod = &channel->chip->zeromod;
			break;
		}
		return;
	}
	if (channel->alg & 0x08) {
		return;
	}
	if (channel->alg & 0x04) {
		channel->pair->out[0] = &channel->chip->zeromod;
		channel->pair->out[1] = &channel->chip->zeromod;
		channel->pair->out[2] = &channel->chip->zeromod;
		channel->pair->out[3] = &channel->chip->zeromod;
		switch (channel->alg & 0x03) {
		case 0x00:channel->pair->slots[0]->mod = &channel->pair->slots[0]->fbmod;
			channel->pair->slots[1]->mod = &channel->pair->slots[0]->out;
			channel->slots[0]->mod = &channel->pair->slots[1]->out;
			channel->slots[1]->mod = &channel->slots[0]->out;
			channel->out[0] = &channel->slots[1]->out;
			channel->out[1] = &channel->chip->zeromod;
			channel->out[2] = &channel->chip->zeromod;
			channel->out[3] = &channel->chip->zeromod;
			break;
		case 0x01:channel->pair->slots[0]->mod = &channel->pair->slots[0]->fbmod;
			channel->pair->slots[1]->mod = &channel->pair->slots[0]->out;
			channel->slots[0]->mod = &channel->chip->zeromod;
			channel->slots[1]->mod = &channel->slots[0]->out;
			channel->out[0] = &channel->pair->slots[1]->out;
			channel->out[1] = &channel->slots[1]->out;
			channel->out[2] = &channel->chip->zeromod;
			channel->out[3] = &channel->chip->zeromod;
			break;
		case 0x02:channel->pair->slots[0]->mod = &channel->pair->slots[0]->fbmod;
			channel->pair->slots[1]->mod = &channel->chip->zeromod;
			channel->slots[0]->mod = &channel->pair->slots[1]->out;
			channel->slots[1]->mod = &channel->slots[0]->out;
			channel->out[0] = &channel->pair->slots[0]->out;
			channel->out[1] = &channel->slots[1]->out;
			channel->out[2] = &channel->chip->zeromod;
			channel->out[3] = &channel->chip->zeromod;
			break;
		case 0x03:channel->pair->slots[0]->mod = &channel->pair->slots[0]->fbmod;
			channel->pair->slots[1]->mod = &channel->chip->zeromod;
			channel->slots[0]->mod = &channel->pair->slots[1]->out;
			channel->slots[1]->mod = &channel->chip->zeromod;
			channel->out[0] = &channel->pair->slots[0]->out;
			channel->out[1] = &channel->slots[0]->out;
			channel->out[2] = &channel->slots[1]->out;
			channel->out[3] = &channel->chip->zeromod;
			break;
		}
	} else {
		switch (channel->alg & 0x01) {
		case 0x00:channel->slots[0]->mod = &channel->slots[0]->fbmod;
			channel->slots[1]->mod = &channel->slots[0]->out;
			channel->out[0] = &channel->slots[1]->out;
			channel->out[1] = &channel->chip->zeromod;
			channel->out[2] = &channel->chip->zeromod;
			channel->out[3] = &channel->chip->zeromod;
			break;
		case 0x01:channel->slots[0]->mod = &channel->slots[0]->fbmod;
			channel->slots[1]->mod = &channel->chip->zeromod;
			channel->out[0] = &channel->slots[0]->out;
			channel->out[1] = &channel->slots[1]->out;
			channel->out[2] = &channel->chip->zeromod;
			channel->out[3] = &channel->chip->zeromod;
			break;
		}
	}
}

static void OPL3_ChannelWriteC0(opl3_channel *channel, Bit8u data) {
	channel->fb = (data & 0x0e) >> 1;
	channel->con = data & 0x01;
	channel->alg = channel->con;
	if (channel->chip->newm) {
		if (channel->chtype == ch_4op) {
			channel->pair->alg = 0x04 | (channel->con << 1) | (channel->pair->con);
			channel->alg = 0x08;
			OPL3_ChannelSetupAlg(channel->pair);
		} else if (channel->chtype == ch_4op2) {
			channel->alg = 0x04 | (channel->pair->con << 1) | (channel->con);
			channel->pair->alg = 0x08;
			OPL3_ChannelSetupAlg(channel);
		} else {
			OPL3_ChannelSetupAlg(channel);
		}
	} else {
		OPL3_ChannelSetupAlg(channel);
	}
	if (channel->chip->newm) {
		channel->cha = ((data >> 4) & 0x01) ? ~0 : 0;
		channel->chb = ((data >> 5) & 0x01) ? ~0 : 0;
	} else {
		channel->cha = channel->chb = ~0;
	}
}

static void OPL3_ChannelKeyOn(opl3_channel *channel) {
	if (channel->chip->newm) {
		if (channel->chtype == ch_4op) {
			OPL3_EnvelopeKeyOn(channel->slots[0], egk_norm);
			OPL3_EnvelopeKeyOn(channel->slots[1], egk_norm);
			OPL3_EnvelopeKeyOn(channel->pair->slots[0], egk_norm);
			OPL3_EnvelopeKeyOn(channel->pair->slots[1], egk_norm);
		} else if (channel->chtype == ch_2op || channel->chtype == ch_drum) {
			OPL3_EnvelopeKeyOn(channel->slots[0], egk_norm);
			OPL3_EnvelopeKeyOn(channel->slots[1], egk_norm);
		}
	} else {
		OPL3_EnvelopeKeyOn(channel->slots[0], egk_norm);
		OPL3_EnvelopeKeyOn(channel->slots[1], egk_norm);
	}
}

static void OPL3_ChannelKeyOff(opl3_channel *channel) {
	if (channel->chip->newm) {
		if (channel->chtype == ch_4op) {
			OPL3_EnvelopeKeyOff(channel->slots[0], egk_norm);
			OPL3_EnvelopeKeyOff(channel->slots[1], egk_norm);
			OPL3_EnvelopeKeyOff(channel->pair->slots[0], egk_norm);
			OPL3_EnvelopeKeyOff(channel->pair->slots[1], egk_norm);
		} else if (channel->chtype == ch_2op || channel->chtype == ch_drum) {
			OPL3_EnvelopeKeyOff(channel->slots[0], egk_norm);
			OPL3_EnvelopeKeyOff(channel->slots[1], egk_norm);
		}
	} else {
		OPL3_EnvelopeKeyOff(channel->slots[0], egk_norm);
		OPL3_EnvelopeKeyOff(channel->slots[1], egk_norm);
	}
}

static void OPL3_ChannelSet4Op(opl3_chip *chip, Bit8u data) {
	Bit8u bit;
	Bit8u chnum;
	for (bit = 0; bit < 6; bit++) {
		chnum = bit;
		if (bit >= 3) {
			chnum += 9 - 3;
		}
		if ((data >> bit) & 0x01) {
			chip->channel[chnum].chtype = ch_4op;
			chip->channel[chnum + 3].chtype = ch_4op2;
		} else {
			chip->channel[chnum].chtype = ch_2op;
			chip->channel[chnum + 3].chtype = ch_2op;
		}
	}
}

static Bit16s OPL3_ClipSample(Bit32s sample) {
	if (sample > 32767) {
		sample = 32767;
	} else if (sample < -32768) {
		sample = -32768;
	}
	return (Bit16s)sample;
}

static void OPL3_GenerateRhythm1(opl3_chip *chip) {
	opl3_channel *channel6;
	opl3_channel *channel7;
	opl3_channel *channel8;
	Bit16u phase14;
	Bit16u phase17;
	Bit16u phase;
	Bit16u phasebit;

	channel6 = &chip->channel[6];
	channel7 = &chip->channel[7];
	channel8 = &chip->channel[8];
	OPL3_SlotGenerate(channel6->slots[0]);
	phase14 = (channel7->slots[0]->pg_phase >> 9) & 0x3ff;
	phase17 = (channel8->slots[1]->pg_phase >> 9) & 0x3ff;
	phase = 0x00;
	//hh tc phase bit
	phasebit = ((phase14 & 0x08) | (((phase14 >> 5) ^ phase14) & 0x04)
		| (((phase17 >> 2) ^ phase17) & 0x08)) ? 0x01 : 0x00;
	//hh
	phase = (phasebit << 9)
		| (0x34 << ((phasebit ^ (chip->noise & 0x01)) << 1));
	OPL3_SlotGeneratePhase(channel7->slots[0], phase);
	//tt
	OPL3_SlotGenerateZM(channel8->slots[0]);
}

static void OPL3_GenerateRhythm2(opl3_chip *chip) {
	opl3_channel *channel6;
	opl3_channel *channel7;
	opl3_channel *channel8;
	Bit16u phase14;
	Bit16u phase17;
	Bit16u phase;
	Bit16u phasebit;

	channel6 = &chip->channel[6];
	channel7 = &chip->channel[7];
	channel8 = &chip->channel[8];
	OPL3_SlotGenerate(channel6->slots[1]);
	phase14 = (channel7->slots[0]->pg_phase >> 9) & 0x3ff;
	phase17 = (channel8->slots[1]->pg_phase >> 9) & 0x3ff;
	phase = 0x00;
	//hh tc phase bit
	phasebit = ((phase14 & 0x08) | (((phase14 >> 5) ^ phase14) & 0x04)
		| (((phase17 >> 2) ^ phase17) & 0x08)) ? 0x01 : 0x00;
	//sd
	phase = (0x100 << ((phase14 >> 8) & 0x01)) ^ ((chip->noise & 0x01) << 8);
	OPL3_SlotGeneratePhase(channel7->slots[1], phase);
	//tc
	phase = 0x100 | (phasebit << 9);
	OPL3_SlotGeneratePhase(channel8->slots[1], phase);
}

void OPL3_Generate(opl3_chip *chip, Bit16s *buf) {
	Bit8u ii;
	Bit8u jj;
	Bit16s accm;

	buf[1] = OPL3_ClipSample(chip->mixbuff[1]);

	for (ii = 0; ii < 12; ii++) {
		OPL3_SlotCalcFB(&chip->slot[ii]);
		OPL3_PhaseGenerate(&chip->slot[ii]);
		OPL3_EnvelopeCalc(&chip->slot[ii]);
		OPL3_SlotGenerate(&chip->slot[ii]);
	}

	for (ii = 12; ii < 15; ii++) {
		OPL3_SlotCalcFB(&chip->slot[ii]);
		OPL3_PhaseGenerate(&chip->slot[ii]);
		OPL3_EnvelopeCalc(&chip->slot[ii]);
	}

	if (chip->rhy & 0x20) {
		OPL3_GenerateRhythm1(chip);
	} else {
		OPL3_SlotGenerate(&chip->slot[12]);
		OPL3_SlotGenerate(&chip->slot[13]);
		OPL3_SlotGenerate(&chip->slot[14]);
	}

	chip->mixbuff[0] = 0;
	for (ii = 0; ii < 18; ii++) {
		accm = 0;
		for (jj = 0; jj < 4; jj++) {
			accm += *chip->channel[ii].out[jj];
		}
		chip->mixbuff[0] += (Bit16s)(accm & chip->channel[ii].cha);
	}

	for (ii = 15; ii < 18; ii++) {
		OPL3_SlotCalcFB(&chip->slot[ii]);
		OPL3_PhaseGenerate(&chip->slot[ii]);
		OPL3_EnvelopeCalc(&chip->slot[ii]);
	}

	if (chip->rhy & 0x20) {
		OPL3_GenerateRhythm2(chip);
	} else {
		OPL3_SlotGenerate(&chip->slot[15]);
		OPL3_SlotGenerate(&chip->slot[16]);
		OPL3_SlotGenerate(&chip->slot[17]);
	}

	buf[0] = OPL3_ClipSample(chip->mixbuff[0]);

	for (ii = 18; ii < 33; ii++) {
		OPL3_SlotCalcFB(&chip->slot[ii]);
		OPL3_PhaseGenerate(&chip->slot[ii]);
		OPL3_EnvelopeCalc(&chip->slot[ii]);
		OPL3_SlotGenerate(&chip->slot[ii]);
	}

	chip->mixbuff[1] = 0;
	for (ii = 0; ii < 18; ii++) {
		accm = 0;
		for (jj = 0; jj < 4; jj++) {
			accm += *chip->channel[ii].out[jj];
		}
		chip->mixbuff[1] += (Bit16s)(accm & chip->channel[ii].chb);
	}

	for (ii = 33; ii < 36; ii++) {
		OPL3_SlotCalcFB(&chip->slot[ii]);
		OPL3_PhaseGenerate(&chip->slot[ii]);
		OPL3_EnvelopeCalc(&chip->slot[ii]);
		OPL3_SlotGenerate(&chip->slot[ii]);
	}

	OPL3_NoiseGenerate(chip);

	if ((chip->timer & 0x3f) == 0x3f) {
		chip->tremolopos = (chip->tremolopos + 1) % 210;
	}
	if (chip->tremolopos < 105) {
		chip->tremolo = chip->tremolopos >> chip->tremoloshift;
	} else {
		chip->tremolo = (210 - chip->tremolopos) >> chip->tremoloshift;
	}

	if ((chip->timer & 0x3ff) == 0x3ff) {
		chip->vibpos = (chip->vibpos + 1) & 7;
	}

	chip->timer++;
}

void OPL3_GenerateResampled(opl3_chip *chip, Bit16s *buf) {
	while (chip->samplecnt >= chip->rateratio) {
		chip->oldsamples[0] = chip->samples[0];
		chip->oldsamples[1] = chip->samples[1];
		OPL3_Generate(chip, chip->samples);
		chip->samplecnt -= chip->rateratio;
	}
	buf[0] = (Bit16s)((chip->oldsamples[0] * (chip->rateratio - chip->samplecnt)
		+ chip->samples[0] * chip->samplecnt) / chip->rateratio);
	buf[1] = (Bit16s)((chip->oldsamples[1] * (chip->rateratio - chip->samplecnt)
		+ chip->samples[1] * chip->samplecnt) / chip->rateratio);
	chip->samplecnt += 1 << RSM_FRAC;
}

void OPL3_Reset(opl3_chip *chip, Bit32u samplerate) {
	Bit8u slotnum;
	Bit8u channum;

	memset(chip, 0, sizeof(opl3_chip));
	for (slotnum = 0; slotnum < 36; slotnum++) {
		chip->slot[slotnum].chip = chip;
		chip->slot[slotnum].mod = &chip->zeromod;
		chip->slot[slotnum].eg_rout = 0x1ff;
		chip->slot[slotnum].eg_out = 0x1ff;
		chip->slot[slotnum].eg_gen = envelope_gen_num_off;
		chip->slot[slotnum].trem = (Bit8u *)&chip->zeromod;
	}
	for (channum = 0; channum < 18; channum++) {
		chip->channel[channum].slots[0] = &chip->slot[ch_slot[channum]];
		chip->channel[channum].slots[1] = &chip->slot[ch_slot[channum] + 3];
		chip->slot[ch_slot[channum]].channel = &chip->channel[channum];
		chip->slot[ch_slot[channum] + 3].channel = &chip->channel[channum];
		if ((channum % 9) < 3) {
			chip->channel[channum].pair = &chip->channel[channum + 3];
		} else if ((channum % 9) < 6) {
			chip->channel[channum].pair = &chip->channel[channum - 3];
		}
		chip->channel[channum].chip = chip;
		chip->channel[channum].out[0] = &chip->zeromod;
		chip->channel[channum].out[1] = &chip->zeromod;
		chip->channel[channum].out[2] = &chip->zeromod;
		chip->channel[channum].out[3] = &chip->zeromod;
		chip->channel[channum].chtype = ch_2op;
		chip->channel[channum].cha = ~0;
		chip->channel[channum].chb = ~0;
		OPL3_ChannelSetupAlg(&chip->channel[channum]);
	}
	chip->noise = 0x306600;
	chip->rateratio = (samplerate << RSM_FRAC) / 49716;
	chip->tremoloshift = 4;
	chip->vibshift = 1;
}

Bit32u OPL3_WriteAddr(opl3_chip *chip, Bit32u port, Bit8u val) {
	Bit16u addr;
	addr = val;
	if ((port & 2) && (addr == 0x05 || chip->newm)) {
		addr |= 0x100;
	}
	return addr;
}

void OPL3_WriteReg(opl3_chip *chip, Bit16u reg, Bit8u v) {
	Bit8u high = (reg >> 8) & 0x01;
	Bit8u regm = reg & 0xff;
	switch (regm & 0xf0) {
	case 0x00:
		if (high) {
			switch (regm & 0x0f) {
			case 0x04:OPL3_ChannelSet4Op(chip, v);
				break;
			case 0x05:chip->newm = v & 0x01;
				break;
			}
		} else {
			switch (regm & 0x0f) {
			case 0x08:chip->nts = (v >> 6) & 0x01;
				break;
			}
		}
		break;
	case 0x20:
	case 0x30:
		if (ad_slot[regm & 0x1f] >= 0) {
			OPL3_SlotWrite20(&chip->slot[18 * high + ad_slot[regm & 0x1f]], v);
		}
		break;
	case 0x40:
	case 0x50:
		if (ad_slot[regm & 0x1f] >= 0) {
			OPL3_SlotWrite40(&chip->slot[18 * high + ad_slot[regm & 0x1f]], v);
		}
		break;
	case 0x60:
	case 0x70:
		if (ad_slot[regm & 0x1f] >= 0) {
			OPL3_SlotWrite60(&chip->slot[18 * high + ad_slot[regm & 0x1f]], v);
		}
		break;
	case 0x80:
	case 0x90:
		if (ad_slot[regm & 0x1f] >= 0) {
			OPL3_SlotWrite80(&chip->slot[18 * high + ad_slot[regm & 0x1f]], v);
		}
		break;
	case 0xe0:
	case 0xf0:
		if (ad_slot[regm & 0x1f] >= 0) {
			OPL3_SlotWriteE0(&chip->slot[18 * high + ad_slot[regm & 0x1f]], v);
		}
		break;
	case 0xa0:
		if ((regm & 0x0f) < 9) {
			OPL3_ChannelWriteA0(&chip->channel[9 * high + (regm & 0x0f)], v);
		}
		break;
	case 0xb0:
		if (regm == 0xbd && !high) {
			chip->tremoloshift = (((v >> 7) ^ 1) << 1) + 2;
			chip->vibshift = ((v >> 6) & 0x01) ^ 1;
			OPL3_ChannelUpdateRhythm(chip, v);
		} else if ((regm & 0x0f) < 9) {
			OPL3_ChannelWriteB0(&chip->channel[9 * high + (regm & 0x0f)], v);
			if (v & 0x20) {
				OPL3_ChannelKeyOn(&chip->channel[9 * high + (regm & 0x0f)]);
			} else {
				OPL3_ChannelKeyOff(&chip->channel[9 * high + (regm & 0x0f)]);
			}
		}
		break;
	case 0xc0:
		if ((regm & 0x0f) < 9) {
			OPL3_ChannelWriteC0(&chip->channel[9 * high + (regm & 0x0f)], v);
		}
		break;
	}
}

void OPL3_GenerateStream(opl3_chip *chip, Bit16s *sndptr, Bit32u numsamples) {
	Bit32u i;

	for (i = 0; i < numsamples; i++) {
		OPL3_GenerateResampled(chip, sndptr);
		sndptr += 2;
	}
}
