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

    Philips SAA1099 Sound driver

    By Juergen Buchmueller and Manuel Abadia

    SAA1099 register layout:
    ========================

    offs | 7654 3210 | description
    -----+-----------+---------------------------
    0x00 | ---- xxxx | Amplitude channel 0 (left)
    0x00 | xxxx ---- | Amplitude channel 0 (right)
    0x01 | ---- xxxx | Amplitude channel 1 (left)
    0x01 | xxxx ---- | Amplitude channel 1 (right)
    0x02 | ---- xxxx | Amplitude channel 2 (left)
    0x02 | xxxx ---- | Amplitude channel 2 (right)
    0x03 | ---- xxxx | Amplitude channel 3 (left)
    0x03 | xxxx ---- | Amplitude channel 3 (right)
    0x04 | ---- xxxx | Amplitude channel 4 (left)
    0x04 | xxxx ---- | Amplitude channel 4 (right)
    0x05 | ---- xxxx | Amplitude channel 5 (left)
    0x05 | xxxx ---- | Amplitude channel 5 (right)
         |           |
    0x08 | xxxx xxxx | Frequency channel 0
    0x09 | xxxx xxxx | Frequency channel 1
    0x0a | xxxx xxxx | Frequency channel 2
    0x0b | xxxx xxxx | Frequency channel 3
    0x0c | xxxx xxxx | Frequency channel 4
    0x0d | xxxx xxxx | Frequency channel 5
         |           |
    0x10 | ---- -xxx | Channel 0 octave select
    0x10 | -xxx ---- | Channel 1 octave select
    0x11 | ---- -xxx | Channel 2 octave select
    0x11 | -xxx ---- | Channel 3 octave select
    0x12 | ---- -xxx | Channel 4 octave select
    0x12 | -xxx ---- | Channel 5 octave select
         |           |
    0x14 | ---- ---x | Channel 0 frequency enable (0 = off, 1 = on)
    0x14 | ---- --x- | Channel 1 frequency enable (0 = off, 1 = on)
    0x14 | ---- -x-- | Channel 2 frequency enable (0 = off, 1 = on)
    0x14 | ---- x--- | Channel 3 frequency enable (0 = off, 1 = on)
    0x14 | ---x ---- | Channel 4 frequency enable (0 = off, 1 = on)
    0x14 | --x- ---- | Channel 5 frequency enable (0 = off, 1 = on)
         |           |
    0x15 | ---- ---x | Channel 0 noise enable (0 = off, 1 = on)
    0x15 | ---- --x- | Channel 1 noise enable (0 = off, 1 = on)
    0x15 | ---- -x-- | Channel 2 noise enable (0 = off, 1 = on)
    0x15 | ---- x--- | Channel 3 noise enable (0 = off, 1 = on)
    0x15 | ---x ---- | Channel 4 noise enable (0 = off, 1 = on)
    0x15 | --x- ---- | Channel 5 noise enable (0 = off, 1 = on)
         |           |
    0x16 | ---- --xx | Noise generator parameters 0
    0x16 | --xx ---- | Noise generator parameters 1
         |           |
    0x18 | --xx xxxx | Envelope generator 0 parameters
    0x18 | x--- ---- | Envelope generator 0 control enable (0 = off, 1 = on)
    0x19 | --xx xxxx | Envelope generator 1 parameters
    0x19 | x--- ---- | Envelope generator 1 control enable (0 = off, 1 = on)
         |           |
    0x1c | ---- ---x | All channels enable (0 = off, 1 = on)
    0x1c | ---- --x- | Synch & Reset generators

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

#include "sndintrf.h"
#include "streams.h"
#include "cpuintrf.h"
#include "cpuexec.h"
#include "saa1099.h"
#include <math.h>


#define LEFT	0x00
#define RIGHT	0x01

/* this structure defines a channel */
struct saa1099_channel
{
	int frequency;			/* frequency (0x00..0xff) */
	int freq_enable;		/* frequency enable */
	int noise_enable;		/* noise enable */
	int octave; 			/* octave (0x00..0x07) */
	int amplitude[2];		/* amplitude (0x00..0x0f) */
	int envelope[2];		/* envelope (0x00..0x0f or 0x10 == off) */

	/* vars to simulate the square wave */
	double counter;
	double freq;
	int level;
};

/* this structure defines a noise channel */
struct saa1099_noise
{
	/* vars to simulate the noise generator output */
	double counter;
	double freq;
	int level;						/* noise polynomal shifter */
};

/* this structure defines a SAA1099 chip */
typedef struct _saa1099_state saa1099_state;
struct _saa1099_state
{
	const device_config *device;
	sound_stream * stream;			/* our stream */
	int noise_params[2];			/* noise generators parameters */
	int env_enable[2];				/* envelope generators enable */
	int env_reverse_right[2];		/* envelope reversed for right channel */
	int env_mode[2];				/* envelope generators mode */
	int env_bits[2];				/* non zero = 3 bits resolution */
	int env_clock[2];				/* envelope clock mode (non-zero external) */
	int env_step[2];                /* current envelope step */
	int all_ch_enable;				/* all channels enable */
	int sync_state;					/* sync all channels */
	int selected_reg;				/* selected register */
	struct saa1099_channel channels[6];    /* channels */
	struct saa1099_noise noise[2];	/* noise generators */
	double sample_rate;
};

static const int amplitude_lookup[16] = {
	 0*32767/16,  1*32767/16,  2*32767/16,	3*32767/16,
	 4*32767/16,  5*32767/16,  6*32767/16,	7*32767/16,
	 8*32767/16,  9*32767/16, 10*32767/16, 11*32767/16,
	12*32767/16, 13*32767/16, 14*32767/16, 15*32767/16
};

static const UINT8 envelope[8][64] = {
	/* zero amplitude */
	{ 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, 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 },
	/* maximum amplitude */
    {15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
	 15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
	 15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
     15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15, },
	/* single decay */
	{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 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,
	  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
	/* repetitive decay */
	{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
	/* single triangular */
	{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 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 },
	/* repetitive triangular */
	{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
	  0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
	/* single attack */
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	  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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
	/* repetitive attack */
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	  0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
      0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
	  0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15 }
};


INLINE saa1099_state *get_safe_token(const device_config *device)
{
	assert(device != NULL);
	assert(device->token != NULL);
	assert(device->type == SOUND);
	assert(sound_get_type(device) == SOUND_SAA1099);
	return (saa1099_state *)device->token;
}


static void saa1099_envelope(saa1099_state *saa, int ch)
{
	if (saa->env_enable[ch])
	{
		int step, mode, mask;
        mode = saa->env_mode[ch];
		/* step from 0..63 and then loop in steps 32..63 */
		step = saa->env_step[ch] =
			((saa->env_step[ch] + 1) & 0x3f) | (saa->env_step[ch] & 0x20);

		mask = 15;
        if (saa->env_bits[ch])
			mask &= ~1; 	/* 3 bit resolution, mask LSB */

        saa->channels[ch*3+0].envelope[ LEFT] =
		saa->channels[ch*3+1].envelope[ LEFT] =
		saa->channels[ch*3+2].envelope[ LEFT] = envelope[mode][step] & mask;
		if (saa->env_reverse_right[ch] & 0x01)
		{
			saa->channels[ch*3+0].envelope[RIGHT] =
			saa->channels[ch*3+1].envelope[RIGHT] =
			saa->channels[ch*3+2].envelope[RIGHT] = (15 - envelope[mode][step]) & mask;
		}
		else
		{
			saa->channels[ch*3+0].envelope[RIGHT] =
			saa->channels[ch*3+1].envelope[RIGHT] =
			saa->channels[ch*3+2].envelope[RIGHT] = envelope[mode][step] & mask;
        }
	}
	else
	{
		/* envelope mode off, set all envelope factors to 16 */
		saa->channels[ch*3+0].envelope[ LEFT] =
		saa->channels[ch*3+1].envelope[ LEFT] =
		saa->channels[ch*3+2].envelope[ LEFT] =
		saa->channels[ch*3+0].envelope[RIGHT] =
		saa->channels[ch*3+1].envelope[RIGHT] =
		saa->channels[ch*3+2].envelope[RIGHT] = 16;
    }
}


static STREAM_UPDATE( saa1099_update )
{
	saa1099_state *saa = param;
    int j, ch;

	/* if the channels are disabled we're done */
	if (!saa->all_ch_enable)
	{
		/* init output data */
		memset(outputs[LEFT],0,samples*sizeof(*outputs[LEFT]));
		memset(outputs[RIGHT],0,samples*sizeof(*outputs[RIGHT]));
        return;
	}

    for (ch = 0; ch < 2; ch++)
    {
		switch (saa->noise_params[ch])
		{
		case 0: saa->noise[ch].freq = 31250.0 * 2; break;
		case 1: saa->noise[ch].freq = 15625.0 * 2; break;
		case 2: saa->noise[ch].freq =  7812.5 * 2; break;
		case 3: saa->noise[ch].freq = saa->channels[ch * 3].freq; break;
		}
	}

    /* fill all data needed */
	for( j = 0; j < samples; j++ )
	{
		int output_l = 0, output_r = 0;

		/* for each channel */
		for (ch = 0; ch < 6; ch++)
		{
            if (saa->channels[ch].freq == 0.0)
                saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
                    (511.0 - (double)saa->channels[ch].frequency);

            /* check the actual position in the square wave */
            saa->channels[ch].counter -= saa->channels[ch].freq;
			while (saa->channels[ch].counter < 0)
			{
				/* calculate new frequency now after the half wave is updated */
				saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
					(511.0 - (double)saa->channels[ch].frequency);

				saa->channels[ch].counter += saa->sample_rate;
				saa->channels[ch].level ^= 1;

				/* eventually clock the envelope counters */
				if (ch == 1 && saa->env_clock[0] == 0)
					saa1099_envelope(saa, 0);
				if (ch == 4 && saa->env_clock[1] == 0)
					saa1099_envelope(saa, 1);
			}

			/* if the noise is enabled */
			if (saa->channels[ch].noise_enable)
			{
				/* if the noise level is high (noise 0: chan 0-2, noise 1: chan 3-5) */
				if (saa->noise[ch/3].level & 1)
				{
					/* subtract to avoid overflows, also use only half amplitude */
					output_l -= saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16 / 2;
					output_r -= saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16 / 2;
				}
			}

			/* if the square wave is enabled */
			if (saa->channels[ch].freq_enable)
			{
				/* if the channel level is high */
				if (saa->channels[ch].level & 1)
				{
					output_l += saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16;
					output_r += saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16;
				}
			}
		}

		for (ch = 0; ch < 2; ch++)
		{
			/* check the actual position in noise generator */
			saa->noise[ch].counter -= saa->noise[ch].freq;
			while (saa->noise[ch].counter < 0)
			{
				saa->noise[ch].counter += saa->sample_rate;
				if( ((saa->noise[ch].level & 0x4000) == 0) == ((saa->noise[ch].level & 0x0040) == 0) )
					saa->noise[ch].level = (saa->noise[ch].level << 1) | 1;
				else
					saa->noise[ch].level <<= 1;
			}
		}
        /* write sound data to the buffer */
		outputs[LEFT][j] = output_l / 6;
		outputs[RIGHT][j] = output_r / 6;
	}
}



static DEVICE_START( saa1099 )
{
	saa1099_state *saa = get_safe_token(device);

	/* copy global parameters */
	saa->device = device;
	saa->sample_rate = device->clock / 256;

	/* for each chip allocate one stream */
	saa->stream = stream_create(device, 0, 2, saa->sample_rate, saa, saa1099_update);
}

WRITE8_DEVICE_HANDLER( saa1099_control_w )
{
	saa1099_state *saa = get_safe_token(device);

	if ((data & 0xff) > 0x1c)
	{
		/* Error! */
                logerror("%s: (SAA1099 '%s') Unknown register selected\n",cpuexec_describe_context(device->machine), device->tag);
	}

	saa->selected_reg = data & 0x1f;
	if (saa->selected_reg == 0x18 || saa->selected_reg == 0x19)
	{
		/* clock the envelope channels */
        if (saa->env_clock[0])
			saa1099_envelope(saa,0);
		if (saa->env_clock[1])
			saa1099_envelope(saa,1);
    }
}


WRITE8_DEVICE_HANDLER( saa1099_data_w )
{
	saa1099_state *saa = get_safe_token(device);
	int reg = saa->selected_reg;
	int ch;

	/* first update the stream to this point in time */
	stream_update(saa->stream);

	switch (reg)
	{
	/* channel i amplitude */
	case 0x00:	case 0x01:	case 0x02:	case 0x03:	case 0x04:	case 0x05:
		ch = reg & 7;
		saa->channels[ch].amplitude[LEFT] = amplitude_lookup[data & 0x0f];
		saa->channels[ch].amplitude[RIGHT] = amplitude_lookup[(data >> 4) & 0x0f];
		break;
	/* channel i frequency */
	case 0x08:	case 0x09:	case 0x0a:	case 0x0b:	case 0x0c:	case 0x0d:
		ch = reg & 7;
		saa->channels[ch].frequency = data & 0xff;
		break;
	/* channel i octave */
	case 0x10:	case 0x11:	case 0x12:
		ch = (reg - 0x10) << 1;
		saa->channels[ch + 0].octave = data & 0x07;
		saa->channels[ch + 1].octave = (data >> 4) & 0x07;
		break;
	/* channel i frequency enable */
	case 0x14:
		saa->channels[0].freq_enable = data & 0x01;
		saa->channels[1].freq_enable = data & 0x02;
		saa->channels[2].freq_enable = data & 0x04;
		saa->channels[3].freq_enable = data & 0x08;
		saa->channels[4].freq_enable = data & 0x10;
		saa->channels[5].freq_enable = data & 0x20;
		break;
	/* channel i noise enable */
	case 0x15:
		saa->channels[0].noise_enable = data & 0x01;
		saa->channels[1].noise_enable = data & 0x02;
		saa->channels[2].noise_enable = data & 0x04;
		saa->channels[3].noise_enable = data & 0x08;
		saa->channels[4].noise_enable = data & 0x10;
		saa->channels[5].noise_enable = data & 0x20;
		break;
	/* noise generators parameters */
	case 0x16:
		saa->noise_params[0] = data & 0x03;
		saa->noise_params[1] = (data >> 4) & 0x03;
		break;
	/* envelope generators parameters */
	case 0x18:	case 0x19:
		ch = reg - 0x18;
		saa->env_reverse_right[ch] = data & 0x01;
		saa->env_mode[ch] = (data >> 1) & 0x07;
		saa->env_bits[ch] = data & 0x10;
		saa->env_clock[ch] = data & 0x20;
		saa->env_enable[ch] = data & 0x80;
		/* reset the envelope */
		saa->env_step[ch] = 0;
		break;
	/* channels enable & reset generators */
	case 0x1c:
		saa->all_ch_enable = data & 0x01;
		saa->sync_state = data & 0x02;
		if (data & 0x02)
		{
			int i;

			/* Synch & Reset generators */
			logerror("%s: (SAA1099 '%s') -reg 0x1c- Chip reset\n",cpuexec_describe_context(device->machine), device->tag);
			for (i = 0; i < 6; i++)
			{
                saa->channels[i].level = 0;
				saa->channels[i].counter = 0.0;
			}
		}
		break;
	default:	/* Error! */
		logerror("%s: (SAA1099 '%s') Unknown operation (reg:%02x, data:%02x)\n",cpuexec_describe_context(device->machine), device->tag, reg, data);
	}
}


/**************************************************************************
 * Generic get_info
 **************************************************************************/

DEVICE_GET_INFO( saa1099 )
{
	switch (state)
	{
		/* --- the following bits of info are returned as 64-bit signed integers --- */
		case DEVINFO_INT_TOKEN_BYTES:					info->i = sizeof(saa1099_state);				break;

		/* --- the following bits of info are returned as pointers to data or functions --- */
		case DEVINFO_FCT_START:							info->start = DEVICE_START_NAME( saa1099 );		break;
		case DEVINFO_FCT_STOP:							/* Nothing */									break;
		case DEVINFO_FCT_RESET:							/* Nothing */									break;

		/* --- the following bits of info are returned as NULL-terminated strings --- */
		case DEVINFO_STR_NAME:							strcpy(info->s, "SAA1099");						break;
		case DEVINFO_STR_FAMILY:					strcpy(info->s, "Philips");						break;
		case DEVINFO_STR_VERSION:					strcpy(info->s, "1.0");							break;
		case DEVINFO_STR_SOURCE_FILE:						strcpy(info->s, __FILE__);						break;
		case DEVINFO_STR_CREDITS:					strcpy(info->s, "Copyright Nicola Salmoria and the MAME Team"); break;
	}
}

