/***************************************************************************

  ay8910.c


  Emulation of the AY-3-8910 / YM2149 sound chip.

  Based on various code snippets by Ville Hallik, Michael Cuddy,
  Tatsuyuki Satoh, Fabrice Frances, Nicola Salmoria.

***************************************************************************/

//
// From mame.txt (http://www.mame.net/readme.html)
//
// VI. Reuse of Source Code
// --------------------------
//    This chapter might not apply to specific portions of MAME (e.g. CPU
//    emulators) which bear different copyright notices.
//    The source code cannot be used in a commercial product without the written
//    authorization of the authors. Use in non-commercial products is allowed, and
//    indeed encouraged.  If you use portions of the MAME source code in your
//    program, however, you must make the full source code freely available as
//    well.
//    Usage of the _information_ contained in the source code is free for any use.
//    However, given the amount of time and energy it took to collect this
//    information, if you find new information we would appreciate if you made it
//    freely available as well.
//


#include "wincompat.h"
#include <stdio.h>
#include <string.h>

#include <SDL/SDL.h>
//#include <unistd.h>
//#include <stdlib.h>

//#include <crtdbg.h>
#include "AY8910.h"

#include "Common.h"
#include "Structs.h"
#include "AppleWin.h"		// For g_fh
#include "Mockingboard.h"	// For g_uTimer1IrqCount

///////////////////////////////////////////////////////////
// typedefs & dummy funcs to allow MAME code to compile:

typedef UINT8 (*mem_read_handler)(UINT32);
typedef void (*mem_write_handler)(UINT32, UINT8);

static void logerror(char* psz, ...)
{
}

static unsigned short activecpu_get_pc()
{
	return 0;
}

//
///////////////////////////////////////////////////////////

#define MAX_OUTPUT 0x7fff

// See AY8910_set_clock() for definition of STEP
#define STEP 0x8000


static int num = 0, ym_num = 0;

struct AY8910
{
	int Channel;
	int SampleRate;
	mem_read_handler PortAread;
	mem_read_handler PortBread;
	mem_write_handler PortAwrite;
	mem_write_handler PortBwrite;
	int register_latch;
	unsigned char Regs[16];
	int lastEnable;
	unsigned int UpdateStep;
	int PeriodA,PeriodB,PeriodC,PeriodN,PeriodE;
	int CountA,CountB,CountC,CountN,CountE;
	unsigned int VolA,VolB,VolC,VolE;
	unsigned char EnvelopeA,EnvelopeB,EnvelopeC;
	unsigned char OutputA,OutputB,OutputC,OutputN;
	signed char CountEnv;
	unsigned char Hold,Alternate,Attack,Holding;
	int RNG;
	unsigned int VolTable[32];
};

/* register id's */
#define AY_AFINE	(0)
#define AY_ACOARSE	(1)
#define AY_BFINE	(2)
#define AY_BCOARSE	(3)
#define AY_CFINE	(4)
#define AY_CCOARSE	(5)
#define AY_NOISEPER	(6)
#define AY_ENABLE	(7)
#define AY_AVOL		(8)
#define AY_BVOL		(9)
#define AY_CVOL		(10)
#define AY_EFINE	(11)
#define AY_ECOARSE	(12)
#define AY_ESHAPE	(13)

#define AY_PORTA	(14)
#define AY_PORTB	(15)


static struct AY8910 AYPSG[MAX_8910];		/* array of PSG's */

static bool g_bAYReset = false;		// Doing AY8910_reset()

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

//#define LOG_AY8910
#ifdef LOG_AY8910
static void LogAY8910(int n, int r, UINT uFreq)
{
	// TO DO: Determine freq from 6522 timer

	if ((g_fh == NULL) || g_bAYReset)
		return;

	static UINT nCnt = 0;
	const UINT nNumAYs = 4;				// 1..4
	if((r == 0))
	{
		if(nCnt == 0)
		{
			fprintf(g_fh, "Time : ");
			for(UINT i=0; i<nNumAYs; i++)
				fprintf(g_fh, "APer BPer CPer NP EN AV BV CV  ");
			fprintf(g_fh, "\n");
		}

		fprintf(g_fh, "%02d.%02d: ", g_uTimer1IrqCount/uFreq, g_uTimer1IrqCount%uFreq);

		for(int j=0; j<n*(3*5+5*3+1); j++)
			fprintf(g_fh, " ");

		UINT i=n;
		{
			UCHAR* pAYRegs = &AYPSG[i].Regs[0];
			fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_AFINE]);
			fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_BFINE]);
			fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_CFINE]);
			fprintf(g_fh, "%02X ", pAYRegs[AY_NOISEPER]);
			fprintf(g_fh, "%02X ", pAYRegs[AY_ENABLE]);
			fprintf(g_fh, "%02X ", pAYRegs[AY_AVOL]);
			fprintf(g_fh, "%02X ", pAYRegs[AY_BVOL]);
			fprintf(g_fh, "%02X  ", pAYRegs[AY_CVOL]);
		}
		fprintf(g_fh, "\n");

		nCnt++;
	}
}
#endif

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

void _AYWriteReg(int n, int r, int v)
{
	struct AY8910 *PSG = &AYPSG[n];
	int old;


	PSG->Regs[r] = v;

#ifdef LOG_AY8910
	LogAY8910(n, r, 60);
#endif

	/* A note about the period of tones, noise and envelope: for speed reasons,*/
	/* we count down from the period to 0, but careful studies of the chip     */
	/* output prove that it instead counts up from 0 until the counter becomes */
	/* greater or equal to the period. This is an important difference when the*/
	/* program is rapidly changing the period to modulate the sound.           */
	/* To compensate for the difference, when the period is changed we adjust  */
	/* our internal counter.                                                   */
	/* Also, note that period = 0 is the same as period = 1. This is mentioned */
	/* in the YM2203 data sheets. However, this does NOT apply to the Envelope */
	/* period. In that case, period = 0 is half as period = 1. */
	switch( r )
	{
	case AY_AFINE:
	case AY_ACOARSE:
		PSG->Regs[AY_ACOARSE] &= 0x0f;
		old = PSG->PeriodA;
		PSG->PeriodA = (PSG->Regs[AY_AFINE] + 256 * PSG->Regs[AY_ACOARSE]) * PSG->UpdateStep;
		if (PSG->PeriodA == 0) PSG->PeriodA = PSG->UpdateStep;
		PSG->CountA += PSG->PeriodA - old;
		if (PSG->CountA <= 0) PSG->CountA = 1;
		break;
	case AY_BFINE:
	case AY_BCOARSE:
		PSG->Regs[AY_BCOARSE] &= 0x0f;
		old = PSG->PeriodB;
		PSG->PeriodB = (PSG->Regs[AY_BFINE] + 256 * PSG->Regs[AY_BCOARSE]) * PSG->UpdateStep;
		if (PSG->PeriodB == 0) PSG->PeriodB = PSG->UpdateStep;
		PSG->CountB += PSG->PeriodB - old;
		if (PSG->CountB <= 0) PSG->CountB = 1;
		break;
	case AY_CFINE:
	case AY_CCOARSE:
		PSG->Regs[AY_CCOARSE] &= 0x0f;
		old = PSG->PeriodC;
		PSG->PeriodC = (PSG->Regs[AY_CFINE] + 256 * PSG->Regs[AY_CCOARSE]) * PSG->UpdateStep;
		if (PSG->PeriodC == 0) PSG->PeriodC = PSG->UpdateStep;
		PSG->CountC += PSG->PeriodC - old;
		if (PSG->CountC <= 0) PSG->CountC = 1;
		break;
	case AY_NOISEPER:
		PSG->Regs[AY_NOISEPER] &= 0x1f;
		old = PSG->PeriodN;
		PSG->PeriodN = PSG->Regs[AY_NOISEPER] * PSG->UpdateStep;
		if (PSG->PeriodN == 0) PSG->PeriodN = PSG->UpdateStep;
		PSG->CountN += PSG->PeriodN - old;
		if (PSG->CountN <= 0) PSG->CountN = 1;
		break;
	case AY_ENABLE:
		if ((PSG->lastEnable == -1) ||
		    ((PSG->lastEnable & 0x40) != (PSG->Regs[AY_ENABLE] & 0x40)))
		{
			/* write out 0xff if port set to input */
			if (PSG->PortAwrite)
				(*PSG->PortAwrite)(0, (UINT8) ((PSG->Regs[AY_ENABLE] & 0x40) ? PSG->Regs[AY_PORTA] : 0xff));	// [TC: UINT8 cast]
		}

		if ((PSG->lastEnable == -1) ||
		    ((PSG->lastEnable & 0x80) != (PSG->Regs[AY_ENABLE] & 0x80)))
		{
			/* write out 0xff if port set to input */
			if (PSG->PortBwrite)
				(*PSG->PortBwrite)(0, (UINT8) ((PSG->Regs[AY_ENABLE] & 0x80) ? PSG->Regs[AY_PORTB] : 0xff));	// [TC: UINT8 cast]
		}

		PSG->lastEnable = PSG->Regs[AY_ENABLE];
		break;
	case AY_AVOL:
		PSG->Regs[AY_AVOL] &= 0x1f;
		PSG->EnvelopeA = PSG->Regs[AY_AVOL] & 0x10;
		PSG->VolA = PSG->EnvelopeA ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_AVOL] ? PSG->Regs[AY_AVOL]*2+1 : 0];
		break;
	case AY_BVOL:
		PSG->Regs[AY_BVOL] &= 0x1f;
		PSG->EnvelopeB = PSG->Regs[AY_BVOL] & 0x10;
		PSG->VolB = PSG->EnvelopeB ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_BVOL] ? PSG->Regs[AY_BVOL]*2+1 : 0];
		break;
	case AY_CVOL:
		PSG->Regs[AY_CVOL] &= 0x1f;
		PSG->EnvelopeC = PSG->Regs[AY_CVOL] & 0x10;
		PSG->VolC = PSG->EnvelopeC ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_CVOL] ? PSG->Regs[AY_CVOL]*2+1 : 0];
		break;
	case AY_EFINE:
	case AY_ECOARSE:
//		_ASSERT((PSG->Regs[AY_EFINE] == 0) && (PSG->Regs[AY_ECOARSE] == 0));
		old = PSG->PeriodE;
		PSG->PeriodE = ((PSG->Regs[AY_EFINE] + 256 * PSG->Regs[AY_ECOARSE])) * PSG->UpdateStep;
		if (PSG->PeriodE == 0) PSG->PeriodE = PSG->UpdateStep / 2;
		PSG->CountE += PSG->PeriodE - old;
		if (PSG->CountE <= 0) PSG->CountE = 1;
		break;
	case AY_ESHAPE:
//		_ASSERT(PSG->Regs[AY_ESHAPE] == 0);
		/* envelope shapes:
		C AtAlH
		0 0 x x  \___

		0 1 x x  /___

		1 0 0 0  \\\\

		1 0 0 1  \___

		1 0 1 0  \/\/
		          ___
		1 0 1 1  \

		1 1 0 0  ////
		          ___
		1 1 0 1  /

		1 1 1 0  /\/\

		1 1 1 1  /___

		The envelope counter on the AY-3-8910 has 16 steps. On the YM2149 it
		has twice the steps, happening twice as fast. Since the end result is
		just a smoother curve, we always use the YM2149 behaviour.
		*/
		PSG->Regs[AY_ESHAPE] &= 0x0f;
		PSG->Attack = (PSG->Regs[AY_ESHAPE] & 0x04) ? 0x1f : 0x00;
		if ((PSG->Regs[AY_ESHAPE] & 0x08) == 0)
		{
			/* if Continue = 0, map the shape to the equivalent one which has Continue = 1 */
			PSG->Hold = 1;
			PSG->Alternate = PSG->Attack;
		}
		else
		{
			PSG->Hold = PSG->Regs[AY_ESHAPE] & 0x01;
			PSG->Alternate = PSG->Regs[AY_ESHAPE] & 0x02;
		}
		PSG->CountE = PSG->PeriodE;
		PSG->CountEnv = 0x1f;
		PSG->Holding = 0;
		PSG->VolE = PSG->VolTable[PSG->CountEnv ^ PSG->Attack];
		if (PSG->EnvelopeA) PSG->VolA = PSG->VolE;
		if (PSG->EnvelopeB) PSG->VolB = PSG->VolE;
		if (PSG->EnvelopeC) PSG->VolC = PSG->VolE;
		break;
	case AY_PORTA:
		if (PSG->Regs[AY_ENABLE] & 0x40)
		{
			if (PSG->PortAwrite)
				(*PSG->PortAwrite)(0, PSG->Regs[AY_PORTA]);
			else
				logerror("PC %04x: warning - write %02x to 8910 #%d Port A\n",activecpu_get_pc(),PSG->Regs[AY_PORTA],n);
		}
		else
		{
			logerror("warning: write to 8910 #%d Port A set as input - ignored\n",n);
		}
		break;
	case AY_PORTB:
		if (PSG->Regs[AY_ENABLE] & 0x80)
		{
			if (PSG->PortBwrite)
				(*PSG->PortBwrite)(0, PSG->Regs[AY_PORTB]);
			else
				logerror("PC %04x: warning - write %02x to 8910 #%d Port B\n",activecpu_get_pc(),PSG->Regs[AY_PORTB],n);
		}
		else
		{
			logerror("warning: write to 8910 #%d Port B set as input - ignored\n",n);
		}
		break;
	}
}


// /length/ is the number of samples we require
// NB. This should be called at twice the 6522 IRQ rate or (eg) 60Hz if no IRQ.
void AY8910Update(int chip,INT16 **buffer,int length)	// [TC: Removed static]
{
	struct AY8910 *PSG = &AYPSG[chip];
	INT16 *buf1,*buf2,*buf3;
	int outn;

	buf1 = buffer[0];
	buf2 = buffer[1];
	buf3 = buffer[2];


	/* The 8910 has three outputs, each output is the mix of one of the three */
	/* tone generators and of the (single) noise generator. The two are mixed */
	/* BEFORE going into the DAC. The formula to mix each channel is: */
	/* (ToneOn | ToneDisable) & (NoiseOn | NoiseDisable). */
	/* Note that this means that if both tone and noise are disabled, the output */
	/* is 1, not 0, and can be modulated changing the volume. */


	/* If the channels are disabled, set their output to 1, and increase the */
	/* counter, if necessary, so they will not be inverted during this update. */
	/* Setting the output to 1 is necessary because a disabled channel is locked */
	/* into the ON state (see above); and it has no effect if the volume is 0. */
	/* If the volume is 0, increase the counter, but don't touch the output. */
	if (PSG->Regs[AY_ENABLE] & 0x01)
	{
		if (PSG->CountA <= length*STEP) PSG->CountA += length*STEP;
		PSG->OutputA = 1;
	}
	else if (PSG->Regs[AY_AVOL] == 0)
	{
		/* note that I do count += length, NOT count = length + 1. You might think */
		/* it's the same since the volume is 0, but doing the latter could cause */
		/* interferencies when the program is rapidly modulating the volume. */
		if (PSG->CountA <= length*STEP) PSG->CountA += length*STEP;
	}
	if (PSG->Regs[AY_ENABLE] & 0x02)
	{
		if (PSG->CountB <= length*STEP) PSG->CountB += length*STEP;
		PSG->OutputB = 1;
	}
	else if (PSG->Regs[AY_BVOL] == 0)
	{
		if (PSG->CountB <= length*STEP) PSG->CountB += length*STEP;
	}
	if (PSG->Regs[AY_ENABLE] & 0x04)
	{
		if (PSG->CountC <= length*STEP) PSG->CountC += length*STEP;
		PSG->OutputC = 1;
	}
	else if (PSG->Regs[AY_CVOL] == 0)
	{
		if (PSG->CountC <= length*STEP) PSG->CountC += length*STEP;
	}

	/* for the noise channel we must not touch OutputN - it's also not necessary */
	/* since we use outn. */
	if ((PSG->Regs[AY_ENABLE] & 0x38) == 0x38)	/* all off */
		if (PSG->CountN <= length*STEP) PSG->CountN += length*STEP;

	outn = (PSG->OutputN | PSG->Regs[AY_ENABLE]);


	/* buffering loop */
	while (length)
	{
		int vola,volb,volc;
		int left;


		/* vola, volb and volc keep track of how long each square wave stays */
		/* in the 1 position during the sample period. */
		vola = volb = volc = 0;

		left = STEP;
		do
		{
			int nextevent;


			if (PSG->CountN < left) nextevent = PSG->CountN;
			else nextevent = left;

			if (outn & 0x08)
			{
				if (PSG->OutputA) vola += PSG->CountA;
				PSG->CountA -= nextevent;
				/* PeriodA is the half period of the square wave. Here, in each */
				/* loop I add PeriodA twice, so that at the end of the loop the */
				/* square wave is in the same status (0 or 1) it was at the start. */
				/* vola is also incremented by PeriodA, since the wave has been 1 */
				/* exactly half of the time, regardless of the initial position. */
				/* If we exit the loop in the middle, OutputA has to be inverted */
				/* and vola incremented only if the exit status of the square */
				/* wave is 1. */
				while (PSG->CountA <= 0)
				{
					PSG->CountA += PSG->PeriodA;
					if (PSG->CountA > 0)
					{
						PSG->OutputA ^= 1;
						if (PSG->OutputA) vola += PSG->PeriodA;
						break;
					}
					PSG->CountA += PSG->PeriodA;
					vola += PSG->PeriodA;
				}
				if (PSG->OutputA) vola -= PSG->CountA;
			}
			else
			{
				PSG->CountA -= nextevent;
				while (PSG->CountA <= 0)
				{
					PSG->CountA += PSG->PeriodA;
					if (PSG->CountA > 0)
					{
						PSG->OutputA ^= 1;
						break;
					}
					PSG->CountA += PSG->PeriodA;
				}
			}

			if (outn & 0x10)
			{
				if (PSG->OutputB) volb += PSG->CountB;
				PSG->CountB -= nextevent;
				while (PSG->CountB <= 0)
				{
					PSG->CountB += PSG->PeriodB;
					if (PSG->CountB > 0)
					{
						PSG->OutputB ^= 1;
						if (PSG->OutputB) volb += PSG->PeriodB;
						break;
					}
					PSG->CountB += PSG->PeriodB;
					volb += PSG->PeriodB;
				}
				if (PSG->OutputB) volb -= PSG->CountB;
			}
			else
			{
				PSG->CountB -= nextevent;
				while (PSG->CountB <= 0)
				{
					PSG->CountB += PSG->PeriodB;
					if (PSG->CountB > 0)
					{
						PSG->OutputB ^= 1;
						break;
					}
					PSG->CountB += PSG->PeriodB;
				}
			}

			if (outn & 0x20)
			{
				if (PSG->OutputC) volc += PSG->CountC;
				PSG->CountC -= nextevent;
				while (PSG->CountC <= 0)
				{
					PSG->CountC += PSG->PeriodC;
					if (PSG->CountC > 0)
					{
						PSG->OutputC ^= 1;
						if (PSG->OutputC) volc += PSG->PeriodC;
						break;
					}
					PSG->CountC += PSG->PeriodC;
					volc += PSG->PeriodC;
				}
				if (PSG->OutputC) volc -= PSG->CountC;
			}
			else
			{
				PSG->CountC -= nextevent;
				while (PSG->CountC <= 0)
				{
					PSG->CountC += PSG->PeriodC;
					if (PSG->CountC > 0)
					{
						PSG->OutputC ^= 1;
						break;
					}
					PSG->CountC += PSG->PeriodC;
				}
			}

			PSG->CountN -= nextevent;
			if (PSG->CountN <= 0)
			{
				/* Is noise output going to change? */
				if ((PSG->RNG + 1) & 2)	/* (bit0^bit1)? */
				{
					PSG->OutputN = ~PSG->OutputN;
					outn = (PSG->OutputN | PSG->Regs[AY_ENABLE]);
				}

				/* The Random Number Generator of the 8910 is a 17-bit shift */
				/* register. The input to the shift register is bit0 XOR bit3 */
				/* (bit0 is the output). This was verified on AY-3-8910 and YM2149 chips. */

				/* The following is a fast way to compute bit17 = bit0^bit3. */
				/* Instead of doing all the logic operations, we only check */
				/* bit0, relying on the fact that after three shifts of the */
				/* register, what now is bit3 will become bit0, and will */
				/* invert, if necessary, bit14, which previously was bit17. */
				if (PSG->RNG & 1) PSG->RNG ^= 0x24000; /* This version is called the "Galois configuration". */
				PSG->RNG >>= 1;
				PSG->CountN += PSG->PeriodN;
			}

			left -= nextevent;
		} while (left > 0);

		/* update envelope */
		if (PSG->Holding == 0)
		{
			PSG->CountE -= STEP;
			if (PSG->CountE <= 0)
			{
				do
				{
					PSG->CountEnv--;
					PSG->CountE += PSG->PeriodE;
				} while (PSG->CountE <= 0);

				/* check envelope current position */
				if (PSG->CountEnv < 0)
				{
					if (PSG->Hold)
					{
						if (PSG->Alternate)
							PSG->Attack ^= 0x1f;
						PSG->Holding = 1;
						PSG->CountEnv = 0;
					}
					else
					{
						/* if CountEnv has looped an odd number of times (usually 1), */
						/* invert the output. */
						if (PSG->Alternate && (PSG->CountEnv & 0x20))
 							PSG->Attack ^= 0x1f;

						PSG->CountEnv &= 0x1f;
					}
				}

				PSG->VolE = PSG->VolTable[PSG->CountEnv ^ PSG->Attack];
				/* reload volume */
				if (PSG->EnvelopeA) PSG->VolA = PSG->VolE;
				if (PSG->EnvelopeB) PSG->VolB = PSG->VolE;
				if (PSG->EnvelopeC) PSG->VolC = PSG->VolE;
			}
		}

#if 0
		*(buf1++) = (vola * PSG->VolA) / STEP;
		*(buf2++) = (volb * PSG->VolB) / STEP;
		*(buf3++) = (volc * PSG->VolC) / STEP;
#else
		// Output PCM wave [-32768...32767] instead of MAME's voltage level [0...32767]
		// - This allows for better s/w mixing

		if(PSG->VolA)
		{
			if(vola)
				*(buf1++) = (vola * PSG->VolA) / STEP;
			else
				*(buf1++) = - (int) PSG->VolA;
		}
		else
		{
			*(buf1++) = 0;
		}

		//

		if(PSG->VolB)
		{
			if(volb)
				*(buf2++) = (volb * PSG->VolB) / STEP;
			else
				*(buf2++) = - (int) PSG->VolB;
		}
		else
		{
			*(buf2++) = 0;
		}

		//

		if(PSG->VolC)
		{
			if(volc)
				*(buf3++) = (volc * PSG->VolC) / STEP;
			else
				*(buf3++) = - (int) PSG->VolC;
		}
		else
		{
			*(buf3++) = 0;
		}
#endif

		length--;
	}
}


static void AY8910_set_clock(int chip,int clock)
{
	struct AY8910 *PSG = &AYPSG[chip];

	/* the step clock for the tone and noise generators is the chip clock    */
	/* divided by 8; for the envelope generator of the AY-3-8910, it is half */
	/* that much (clock/16), but the envelope of the YM2149 goes twice as    */
	/* fast, therefore again clock/8.                                        */
	/* Here we calculate the number of steps which happen during one sample  */
	/* at the given sample rate. No. of events = sample rate / (clock/8).    */
	/* STEP is a multiplier used to turn the fraction into a fixed point     */
	/* number.                                                               */
	PSG->UpdateStep = (unsigned int) (((double)STEP * PSG->SampleRate * 8 + clock/2) / clock);	// [TC: unsigned int cast]
}


static void build_mixer_table(int chip)
{
	struct AY8910 *PSG = &AYPSG[chip];
	int i;
	double out;


	/* calculate the volume->voltage conversion table */
	/* The AY-3-8910 has 16 levels, in a logarithmic scale (3dB per step) */
	/* The YM2149 still has 16 levels for the tone generators, but 32 for */
	/* the envelope generator (1.5dB per step). */
	out = MAX_OUTPUT;
	for (i = 31;i > 0;i--)
	{
		PSG->VolTable[i] = (unsigned int) (out + 0.5);	/* round to nearest */	// [TC: unsigned int cast]

		out /= 1.188502227;	/* = 10 ^ (1.5/20) = 1.5dB */
	}
	PSG->VolTable[0] = 0;
}


#if 0
void ay8910_write_ym(int chip, int addr, int data)
{
	struct AY8910 *PSG = &AYPSG[chip];

//	if (addr & 1)
//	{	/* Data port */
//		int r = PSG->register_latch;
		int r = addr;

		if (r > 15) return;
		if (r < 14)
		{
			if (r == AY_ESHAPE || PSG->Regs[r] != data)
			{
				/* update the output buffer before changing the register */
//				stream_update(PSG->Channel,0);
				AY8910Update(chip, INT16 **buffer, int length)
			}
		}

		_AYWriteReg(PSG,r,data);
	}
//	else
//	{	/* Register port */
//		PSG->register_latch = data & 0x0f;
//	}
}
#endif


void AY8910_reset(int chip)
{
	g_bAYReset = true;

	int i;
	struct AY8910 *PSG = &AYPSG[chip];

	PSG->register_latch = 0;
	PSG->RNG = 1;
	PSG->OutputA = 0;
	PSG->OutputB = 0;
	PSG->OutputC = 0;
	PSG->OutputN = 0xff;
	PSG->lastEnable = -1;	/* force a write */
	for (i = 0;i < AY_PORTA;i++)
		_AYWriteReg(chip,i,0);	/* AYWriteReg() uses the timer system; we cannot */
								/* call it at this time because the timer system */
								/* has not been initialized. */

	g_bAYReset = false;
}

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

void AY8910_InitAll(int nClock, int nSampleRate)
{
	for(int nChip=0; nChip<MAX_8910; nChip++)
	{
		struct AY8910 *PSG = &AYPSG[nChip];

		memset(PSG,0,sizeof(struct AY8910));
		PSG->SampleRate = nSampleRate;

		PSG->PortAread = NULL;
		PSG->PortBread = NULL;
		PSG->PortAwrite = NULL;
		PSG->PortBwrite = NULL;

		AY8910_set_clock(nChip, nClock);

		build_mixer_table(nChip);
	}
}

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

void AY8910_InitClock(int nClock)
{
	for(int nChip=0; nChip<MAX_8910; nChip++)
	{
		AY8910_set_clock(nChip, nClock);
	}
}

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

BYTE* AY8910_GetRegsPtr(UINT nAyNum)
{
	if(nAyNum >= MAX_8910)
		return NULL;

	return &AYPSG[nAyNum].Regs[0];
}