musix 0.3.5

// ---------------------------------------------------------------------------
//	OPM interface
//	Copyright (C) cisc 1998, 2003.
// ---------------------------------------------------------------------------
//	$Id: opm.cpp,v 1.26 2003/08/25 13:53:08 cisc Exp $

#include "headers.h"
#include "misc.h"
#include "opm.h"
#include "fmgeninl.h"

//#define LOGNAME "opm"

namespace FM
{

int OPM::amtable[4][OPM_LFOENTS] = { -1, };
int OPM::pmtable[4][OPM_LFOENTS];

// ---------------------------------------------------------------------------
//	構築
//
OPM::OPM()
{
	lfo_count_ = 0;
	lfo_count_prev_ = ~0;
	BuildLFOTable();
	for (int i=0; i<8; i++)
	{
		ch[i].SetChip(&chip);
		ch[i].SetType(typeM);
	}
}

// ---------------------------------------------------------------------------
//	初期化
//
bool OPM::Init(uint c, uint rf, bool ip)
{
	if (!SetRate(c, rf, ip))
		return false;
	
	Reset();

	SetVolume(0);
	SetChannelMask(0);
	return true;
}

// ---------------------------------------------------------------------------
//	再設定
//
bool OPM::SetRate(uint c, uint r, bool)
{
	clock = c;
	pcmrate = r;
	rate = r;

	RebuildTimeTable();
	
	return true;
}

// ---------------------------------------------------------------------------
//	チャンネルマスクの設定
//
void OPM::SetChannelMask(uint mask)
{
	for (int i=0; i<8; i++)
		ch[i].Mute(!!(mask & (1 << i)));
}

// ---------------------------------------------------------------------------
//	リセット
//
void OPM::Reset()
{
	int i;
	for (i=0x0; i<0x100; i++) SetReg(i, 0);
	SetReg(0x19, 0x80);
	Timer::Reset();
	
	status = 0;
	noise = 12345;
	noisecount = 0;
	
	for (i=0; i<8; i++)
		ch[i].Reset();
}

// ---------------------------------------------------------------------------
//	設定に依存するテーブルの作成
//
void OPM::RebuildTimeTable()
{
	uint fmclock = clock / 64;

	assert(fmclock < (0x80000000 >> FM_RATIOBITS));
	rateratio = ((fmclock << FM_RATIOBITS) + rate/2) / rate;
	SetTimerBase(fmclock);
	
//	FM::MakeTimeTable(rateratio);
	chip.SetRatio(rateratio);

//	lfo_diff_ = 


//	lfodcount = (16 + (lfofreq & 15)) << (lfofreq >> 4);
//	lfodcount = lfodcount * rateratio >> FM_RATIOBITS;
}

// ---------------------------------------------------------------------------
//	タイマー A 発生時イベント (CSM)
//
void OPM::TimerA()
{
	if (regtc & 0x80)
	{
		for (int i=0; i<8; i++)
		{
			ch[i].KeyControl(0);
			ch[i].KeyControl(0xf);
		}
	}
}

// ---------------------------------------------------------------------------
//	音量設定
//
void OPM::SetVolume(int db)
{
	db = Min(db, 20);
	if (db > -192)
		fmvolume = int(16384.0 * pow(10.0, db / 40.0));
	else
		fmvolume = 0;
}

// ---------------------------------------------------------------------------
//	ステータスフラグ設定
//
void OPM::SetStatus(uint bits)
{
	if (!(status & bits))
	{
		status |= bits;
		Intr(true);
	}
}

// ---------------------------------------------------------------------------
//	ステータスフラグ解除
//
void OPM::ResetStatus(uint bits)
{
	if (status & bits)
	{
		status &= ~bits;
		if (!status)
			Intr(false);
	}
}

// ---------------------------------------------------------------------------
//	レジスタアレイにデータを設定
//
void OPM::SetReg(uint addr, uint data)
{
	if (addr >= 0x100)
		return;
	
	int c = addr & 7;
	switch (addr & 0xff)
	{
	case 0x01:					// TEST (lfo restart)
		if (data & 2)
		{
			lfo_count_ = 0; 
			lfo_count_prev_ = ~0;
		}
		reg01 = data;
		break;
		
	case 0x08:					// KEYON
		if (!(regtc & 0x80))
			ch[data & 7].KeyControl(data >> 3);
		else
		{
			c = data & 7;
			if (!(data & 0x08)) ch[c].op[0].KeyOff();
			if (!(data & 0x10)) ch[c].op[1].KeyOff();
			if (!(data & 0x20)) ch[c].op[2].KeyOff();
			if (!(data & 0x40)) ch[c].op[3].KeyOff();
		}
		break;
		
	case 0x10: case 0x11:		// CLKA1, CLKA2
		SetTimerA(addr, data);
		break;

	case 0x12:					// CLKB
		SetTimerB(data);
		break;

	case 0x14:					// CSM, TIMER
		SetTimerControl(data);
		break;
	
	case 0x18:					// LFRQ(lfo freq)
		lfofreq = data;

		assert(16-4-FM_RATIOBITS >= 0);
		lfo_count_diff_ = 
			rateratio 
			* ((16 + (lfofreq & 15)) << (16 - 4 - FM_RATIOBITS)) 
			/ (1 << (15 - (lfofreq >> 4)));
		
		break;
		
	case 0x19:					// PMD/AMD
		(data & 0x80 ? pmd : amd) = data & 0x7f;
		break;

	case 0x1b:					// CT, W(lfo waveform)
		lfowaveform = data & 3;
		break;

								// RL, FB, Connect
	case 0x20: case 0x21: case 0x22: case 0x23:
	case 0x24: case 0x25: case 0x26: case 0x27:
		ch[c].SetFB((data >> 3) & 7);
		ch[c].SetAlgorithm(data & 7);
		pan[c] = (data >> 6) & 3;
		break;
		
								// KC
	case 0x28: case 0x29: case 0x2a: case 0x2b:
	case 0x2c: case 0x2d: case 0x2e: case 0x2f:
		kc[c] = data;
		ch[c].SetKCKF(kc[c], kf[c]);
		break;
		
								// KF
	case 0x30: case 0x31: case 0x32: case 0x33:
	case 0x34: case 0x35: case 0x36: case 0x37:
		kf[c] = data >> 2;
		ch[c].SetKCKF(kc[c], kf[c]);
		break;
		
								// PMS, AMS
	case 0x38: case 0x39: case 0x3a: case 0x3b:
	case 0x3c: case 0x3d: case 0x3e: case 0x3f:
		ch[c].SetMS((data << 4) | (data >> 4));
		break;
	
	case 0x0f:			// NE/NFRQ (noise)
		noisedelta = data;
		noisecount = 0;
		break;
		
	default:
		if (addr >= 0x40)
			OPM::SetParameter(addr, data);
		break;
	}
}


// ---------------------------------------------------------------------------
//	パラメータセット
//
void OPM::SetParameter(uint addr, uint data)
{
	const static uint8 sltable[16] = 
	{
		  0,   4,   8,  12,  16,  20,  24,  28,
		 32,  36,  40,  44,  48,  52,  56, 124,
	};
	const static uint8 slottable[4] = { 0, 2, 1, 3 };

	uint slot = slottable[(addr >> 3) & 3];
	Operator* op = &ch[addr & 7].op[slot];

	switch ((addr >> 5) & 7)
	{
	case 2:	// 40-5F DT1/MULTI
		op->SetDT((data >> 4) & 0x07);
		op->SetMULTI(data & 0x0f);
		break;
		
	case 3: // 60-7F TL
		op->SetTL(data & 0x7f, (regtc & 0x80) != 0);
		break;
		
	case 4: // 80-9F KS/AR
		op->SetKS((data >> 6) & 3);
		op->SetAR((data & 0x1f) * 2);
		break;
		
	case 5: // A0-BF DR/AMON(D1R/AMS-EN)
		op->SetDR((data & 0x1f) * 2);
		op->SetAMON((data & 0x80) != 0);
		break;
		
	case 6: // C0-DF SR(D2R), DT2
		op->SetSR((data & 0x1f) * 2);
		op->SetDT2((data >> 6) & 3);
		break;
		
	case 7:	// E0-FF SL(D1L)/RR
		op->SetSL(sltable[(data >> 4) & 15]);
		op->SetRR((data & 0x0f) * 4 + 2);
		break;
	}
}

// ---------------------------------------------------------------------------
//
//
void OPM::BuildLFOTable()
{
	if (amtable[0][0] != -1)
		return;

	for (int type=0; type<4; type++)
	{
		int r = 0;
		for (int c=0; c<OPM_LFOENTS; c++)
		{
			int a, p;
			
			switch (type)
			{
			case 0:
				p = (((c + 0x100) & 0x1ff) / 2) - 0x80;
				a = 0xff - c / 2;
				break;

			case 1:
				a = c < 0x100 ? 0xff : 0;
				p = c < 0x100 ? 0x7f : -0x80;
				break;

			case 2:
				p = (c + 0x80) & 0x1ff;
				p = p < 0x100 ? p - 0x80 : 0x17f - p;
				a = c < 0x100 ? 0xff - c : c - 0x100;
				break;

			case 3:
				if (!(c & 3))
					r = (rand() / 17) & 0xff;
				a = r;
				p = r - 0x80;
				break;
			}

			amtable[type][c] = a;
			pmtable[type][c] = -p-1;
//			printf("%d ", p);
		}
	}
}

// ---------------------------------------------------------------------------

inline void OPM::LFO()
{
	if (lfowaveform != 3)
	{
//		if ((lfo_count_ ^ lfo_count_prev_) & ~((1 << 15) - 1))
		{
			int c = (lfo_count_ >> 15) & 0x1fe;
//	fprintf(stderr, "%.8x %.2x\n", lfo_count_, c);
			chip.SetPML(pmtable[lfowaveform][c] * pmd / 128 + 0x80);
			chip.SetAML(amtable[lfowaveform][c] * amd / 128);
		}
	}
	else
	{
		if ((lfo_count_ ^ lfo_count_prev_) & ~((1 << 17) - 1))
		{
			int c = (rand() / 17) & 0xff;
			chip.SetPML((c - 0x80) * pmd / 128 + 0x80);
			chip.SetAML(c * amd / 128);
		}
	}
	lfo_count_prev_ = lfo_count_;
	lfo_step_++;
	if ((lfo_step_ & 7) == 0)
	{
		lfo_count_ += lfo_count_diff_;
	}
}

inline uint OPM::Noise()
{
	noisecount += 2 * rateratio;
	if (noisecount >= (32 << FM_RATIOBITS))
	{
		int n = 32 - (noisedelta & 0x1f);
		if (n == 1)
			n = 2;

		noisecount = noisecount - (n << FM_RATIOBITS);
		if ((noisedelta & 0x1f) == 0x1f) 
			noisecount -= FM_RATIOBITS;
		noise = (noise >> 1) ^ (noise & 1 ? 0x8408 : 0);
	}
	return noise;
}

// ---------------------------------------------------------------------------
//	合成の一部
//
inline void OPM::MixSub(int activech, ISample** idest)
{
	if (activech & 0x4000) (*idest[0]  = ch[0].Calc());
	if (activech & 0x1000) (*idest[1] += ch[1].Calc());
	if (activech & 0x0400) (*idest[2] += ch[2].Calc());
	if (activech & 0x0100) (*idest[3] += ch[3].Calc());
	if (activech & 0x0040) (*idest[4] += ch[4].Calc());
	if (activech & 0x0010) (*idest[5] += ch[5].Calc());
	if (activech & 0x0004) (*idest[6] += ch[6].Calc());
	if (activech & 0x0001)
	{
		if (noisedelta & 0x80)
			*idest[7] += ch[7].CalcN(Noise());
		else
			*idest[7] += ch[7].Calc();
	}
}

inline void OPM::MixSubL(int activech, ISample** idest)
{
	if (activech & 0x4000) (*idest[0]  = ch[0].CalcL());
	if (activech & 0x1000) (*idest[1] += ch[1].CalcL());
	if (activech & 0x0400) (*idest[2] += ch[2].CalcL());
	if (activech & 0x0100) (*idest[3] += ch[3].CalcL());
	if (activech & 0x0040) (*idest[4] += ch[4].CalcL());
	if (activech & 0x0010) (*idest[5] += ch[5].CalcL());
	if (activech & 0x0004) (*idest[6] += ch[6].CalcL());
	if (activech & 0x0001)
	{
		if (noisedelta & 0x80)
			*idest[7] += ch[7].CalcLN(Noise());
		else
			*idest[7] += ch[7].CalcL();
	}
}


// ---------------------------------------------------------------------------
//	合成 (stereo)
//
void OPM::Mix(Sample* buffer, int nsamples)
{
#define IStoSample(s)	((Limit(s, 0xffff, -0x10000) * fmvolume) >> 14)

//#define IStoSample(s)	((s * fmvolume) >> 14)
	
	// odd bits - active, even bits - lfo
	uint activech=0;
	for (int i=0; i<8; i++)
		activech = (activech << 2) | ch[i].Prepare();

	if (activech & 0x5555)
	{
		// LFO 波形初期化ビット = 1 ならば LFO はかからない?
		if (reg01 & 0x02)
			activech &= 0x5555;

		// Mix
		ISample ibuf[8];
		ISample* idest[8];
		idest[0] = &ibuf[pan[0]];
		idest[1] = &ibuf[pan[1]];
		idest[2] = &ibuf[pan[2]];
		idest[3] = &ibuf[pan[3]];
		idest[4] = &ibuf[pan[4]];
		idest[5] = &ibuf[pan[5]];
		idest[6] = &ibuf[pan[6]];
		idest[7] = &ibuf[pan[7]];
		
		Sample* limit = buffer + nsamples * 2;
		for (Sample* dest = buffer; dest < limit; dest+=2)
		{
			ibuf[1] = ibuf[2] = ibuf[3] = 0;
			if (activech & 0xaaaa)
				LFO(), MixSubL(activech, idest);
			else
				LFO(), MixSub(activech, idest);

			StoreSample(dest[0], IStoSample(ibuf[1] + ibuf[3]));
			StoreSample(dest[1], IStoSample(ibuf[2] + ibuf[3]));
		}
	}
#undef IStoSample
}

}	// namespace FM