mame/src/mess/audio/mea8000.c

743 lines
20 KiB
C

/**********************************************************************
Copyright (C) Antoine Mine' 2006
Philips / Signetics MEA 8000 emulation.
The MEA 8000 is a speech synthesis chip.
The French company TMPI (Techni-musique & parole informatique) provided
speech extensions for several 8-bit computers (Thomson, Amstrad, Oric).
It was quite popular in France because of its ability to spell 'u'
(unlike the more widespread SPO 296 chip).
The synthesis is based on a 4-formant model.
First, an initial sawtooth noise signal is generated.
The signal passes through a cascade of 4 filters of increasing frequency.
Each filter is a second order digital filter with a programmable
frequency and bandwidth.
All parameters, including filter parameters, are smoothly interpolated
for the duration of a frame (8ms, 16ms, 32ms, or 64 ms).
TODO:
- REQ output pin
- optimize mea8000_compute_sample
- should we accept new frames in slow-stop mode ?
**********************************************************************/
#include <math.h>
#include "emu.h"
#include "mea8000.h"
#include "sound/dac.h"
#define VERBOSE 0
/* define to use double instead of int (slow but useful for debugging) */
#undef FLOAT_MODE
/******************* internal chip data structure ******************/
/* finite machine state controling frames */
enum mea8000_state
{
MEA8000_STOPPED, /* nothing to do, timer disabled */
MEA8000_WAIT_FIRST, /* received pitch, wait for first full trame, timer disabled */
MEA8000_STARTED, /* playing a frame, timer on */
MEA8000_SLOWING, /* repating last frame with decreasing amplitude, timer on */
};
ALLOW_SAVE_TYPE( mea8000_state );
struct filter_t
{
#ifdef FLOAT_MODE
double fm, last_fm; /* frequency, in Hz */
double bw, last_bw; /* band-width, in Hz */
double output, last_output; /* filter state */
#else
UINT16 fm, last_fm;
UINT16 bw, last_bw;
INT32 output, last_output;
#endif
};
struct mea8000_t
{
/* configuration parameters */
const mea8000_interface* iface;
/* state */
mea8000_state state; /* current state */
UINT8 buf[4]; /* store 4 consecutive data to form a frame info */
UINT8 bufpos; /* new byte to write in frame info buffer */
UINT8 cont; /* if no data 0=stop 1=repeat last frame */
UINT8 roe; /* enable req output, now unimplemented */
UINT16 framelength; /* in samples */
UINT16 framepos; /* in samples */
UINT16 framelog; /* log2 of framelength */
INT16 lastsample, sample; /* output samples are interpolated */
UINT32 phi; /* absolute phase for frequency / noise generator */
filter_t f[4]; /* filters */
UINT16 last_ampl, ampl; /* amplitude * 1000 */
UINT16 last_pitch, pitch; /* pitch of sawtooth signal, in Hz */
UINT8 noise;
emu_timer *timer;
devcb_resolved_write8 req_out;
};
/******************* utilitiy function and macros ********************/
#define LOG(x) do { if (VERBOSE) logerror x; } while (0)
/* digital filters work at 8 kHz */
#define F0 8096
/* filtered output is supersampled x 8 */
#define SUPERSAMPLING 8
/* actual output pediod */
#define SAMPLING attotime::from_hz((SUPERSAMPLING*F0))
INLINE mea8000_t* get_safe_token( device_t *device )
{
assert( device != NULL );
assert( device->type() == MEA8000);
return (mea8000_t*) downcast<mea8000_device *>(device)->token();
}
/************************* quantization tables ***********************/
/* frequency, in Hz */
static const int fm1_table[32] =
{
150, 162, 174, 188, 202, 217, 233, 250,
267, 286, 305, 325, 346, 368, 391, 415,
440, 466, 494, 523, 554, 587, 622, 659,
698, 740, 784, 830, 880, 932, 988, 1047
};
static const int fm2_table[32] =
{
440, 466, 494, 523, 554, 587, 622, 659,
698, 740, 784, 830, 880, 932, 988, 1047,
1100, 1179, 1254, 1337, 1428, 1528, 1639, 1761,
1897, 2047, 2214, 2400, 2609, 2842, 3105, 3400
};
static const int fm3_table[8] =
{
1179, 1337, 1528, 1761, 2047, 2400, 2842, 3400
};
static const int fm4_table[1] = { 3500 };
/* bandwidth, in Hz */
static const int bw_table[4] = { 726, 309, 125, 50 };
/* amplitude * 1000 */
static const int ampl_table[16] =
{
0, 8, 11, 16, 22, 31, 44, 62,
88, 125, 177, 250, 354, 500, 707, 1000
};
/* pitch increment, in Hz / 8 ms */
static const int pi_table[32] =
{
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
0 /* noise */, -15, -14, -13, -12, -11, -10, -9,
-8, -7, -6, -5, -4, -3, -2, -1
};
/***************************** REQ **********************************/
static int mea8000_accept_byte( mea8000_t* mea8000 )
{
return
mea8000->state == MEA8000_STOPPED ||
mea8000->state == MEA8000_WAIT_FIRST ||
(mea8000->state == MEA8000_STARTED && mea8000->bufpos < 4);
}
static void mea8000_update_req( device_t *device )
{
mea8000_t* mea8000 = get_safe_token( device );
/* actually, req pulses less than 3us for each new byte,
it goes back up if there space left in the buffer, or stays low if the
buffer contains a complete frame and the CPU nees to wait for the next
frame end to compose a new frame.
*/
if (!mea8000->req_out.isnull())
mea8000->req_out( 0, mea8000_accept_byte( mea8000 ) );
}
/*********************** sound generation ***************************/
/* table amplitude [-QUANT,QUANT] */
#define QUANT 512
/* filter coefficients from frequencies */
#define TABLE_LEN 3600
static int cos_table[TABLE_LEN]; /* fm => cos coefficient */
static int exp_table[TABLE_LEN]; /* bw => exp coefficient */
static int exp2_table[TABLE_LEN]; /* bw => 2*exp coefficient */
/* noise generator table */
#define NOISE_LEN 8192
static int noise_table[NOISE_LEN];
/* precompute tables */
static void mea8000_init_tables( running_machine &machine )
{
int i;
for (i=0; i<TABLE_LEN; i++)
{
double f = (double)i / F0;
cos_table[i] = 2. * cos(2.*M_PI*f) * QUANT;
exp_table[i] = exp(-M_PI*f) * QUANT;
exp2_table[i] = exp(-2*M_PI*f) * QUANT;
}
for (i=0; i<NOISE_LEN; i++)
noise_table[i] = (machine.rand() % (2*QUANT)) - QUANT;
}
#ifndef FLOAT_MODE /* UINT16 version */
/* linear interpolation */
static int mea8000_interp( mea8000_t* mea8000, UINT16 org, UINT16 dst )
{
return org + (((dst-org) * mea8000->framepos) >> mea8000->framelog);
}
/* apply second order digital filter, sampling at F0 */
static int mea8000_filter_step( mea8000_t* mea8000, int i, int input )
{
/* frequency */
int fm = mea8000_interp(mea8000, mea8000->f[i].last_fm, mea8000->f[i].fm);
/* bandwidth */
int bw = mea8000_interp(mea8000, mea8000->f[i].last_bw, mea8000->f[i].bw);
/* filter coefficients */
int b = (cos_table[fm] * exp_table[bw]) / QUANT;
int c = exp2_table[bw];
/* transfer function */
int next_output = input + (b * mea8000->f[i].output - c * mea8000->f[i].last_output) / QUANT;
mea8000->f[i].last_output = mea8000->f[i].output;
mea8000->f[i].output = next_output;
return next_output;
}
/* random waveform, in [-QUANT,QUANT] */
static int mea8000_noise_gen( mea8000_t* mea8000 )
{
mea8000->phi = (mea8000->phi + 1) % NOISE_LEN;
return noise_table[mea8000->phi];
}
/* sawtooth waveform at F0, in [-QUANT,QUANT] */
static int mea8000_freq_gen( mea8000_t* mea8000 )
{
int pitch = mea8000_interp(mea8000, mea8000->last_pitch, mea8000->pitch);
mea8000->phi = (mea8000->phi + pitch) % F0;
return ((mea8000->phi % F0) * QUANT * 2) / F0 - QUANT;
}
/* sample in [-32768,32767], at F0 */
static int mea8000_compute_sample( mea8000_t* mea8000 )
{
int i;
int out;
int ampl = mea8000_interp(mea8000, mea8000->last_ampl, mea8000->ampl);
if (mea8000->noise)
out = mea8000_noise_gen(mea8000);
else
out = mea8000_freq_gen(mea8000);
out *= ampl / 32;
for (i=0; i<4; i++)
{
out = mea8000_filter_step(mea8000, i, out);
}
if ( out > 32767 )
out = 32767;
if ( out < -32767)
out = -32767;
return out;
}
#else /* float version */
/* linear interpolation */
static double mea8000_interp( mea8000_t* mea8000, double org, double dst )
{
return org + ((dst-org) * mea8000->framepos) / mea8000->framelength;
}
/* apply second order digital filter, sampling at F0 */
static double mea8000_filter_step( mea8000_t* mea8000, int i, double input )
{
double fm = mea8000_interp(mea8000, mea8000->f[i].last_fm, mea8000->f[i].fm);
double bw = mea8000_interp(mea8000, mea8000->f[i].last_bw, mea8000->f[i].bw);
double b = 2.*cos(2.*M_PI*fm/F0);
double c = -exp(-M_PI*bw/F0);
double next_output =
input -
c * (b * mea8000->f[i].output + c * mea8000->f[i].last_output);
mea8000->f[i].last_output = mea8000->f[i].output;
mea8000->f[i].output = next_output;
return next_output;
}
/* noise, in [-1,1] */
static double mea8000_noise_gen( mea8000_t* mea8000 )
{
mea8000->phi++;
return (double) noise_table[mea8000->phi % NOISE_LEN] / QUANT;
}
/* sawtooth waveform at F0, in [-1,1] */
static double mea8000_freq_gen( mea8000_t* mea8000 )
{
int pitch = mea8000_interp(mea8000, mea8000->last_pitch, mea8000->pitch);
mea8000->phi += pitch;
return (double) (mea8000->phi % F0) / (F0/2.) - 1.;
}
/* sample in [-32767,32767], at F0 */
static int mea8000_compute_sample( mea8000_t* mea8000 )
{
int i;
double out;
double ampl = mea8000_interp(mea8000, 8.*mea8000->last_ampl, 8.*mea8000->ampl);
if (mea8000->noise)
out = mea8000_noise_gen(mea8000);
else
out = mea8000_freq_gen(mea8000);
out *= ampl;
for (i=0; i<4; i++)
{
out = mea8000_filter_step(mea8000, i, out);
}
if ( out > 32767 )
out = 32767;
if ( out < -32767)
out = -32767;
return out;
}
#endif
/*********************** frame management ***************************/
/* shift frame parameters from current to last */
static void mea8000_shift_frame( mea8000_t* mea8000 )
{
int i;
mea8000->last_pitch = mea8000->pitch;
for (i=0; i<4; i++)
{
mea8000->f[i].last_bw = mea8000->f[i].bw;
mea8000->f[i].last_fm = mea8000->f[i].fm;
}
mea8000->last_ampl = mea8000->ampl;
}
/* decode fields from buffer to current frame */
static void mea8000_decode_frame( mea8000_t* mea8000 )
{
int fd = (mea8000->buf[3] >> 5) & 3; /* 0=8ms, 1=16ms, 2=32ms, 3=64ms */
int pi = pi_table[ mea8000->buf[3] & 0x1f ] << fd;
mea8000->noise = (mea8000->buf[3] & 0x1f) == 16;
mea8000->pitch = mea8000->last_pitch + pi;
mea8000->f[0].bw = bw_table[ mea8000->buf[0] >> 6 ];
mea8000->f[1].bw = bw_table[ (mea8000->buf[0] >> 4) & 3 ];
mea8000->f[2].bw = bw_table[ (mea8000->buf[0] >> 2) & 3 ];
mea8000->f[3].bw = bw_table[ mea8000->buf[0] & 3 ];
mea8000->f[3].fm = fm4_table[ 0 ];
mea8000->f[2].fm = fm3_table[ mea8000->buf[1] >> 5 ];
mea8000->f[1].fm = fm2_table[ mea8000->buf[1] & 0x1f ];
mea8000->f[0].fm = fm1_table[ mea8000->buf[2] >> 3 ];
mea8000->ampl = ampl_table[ ((mea8000->buf[2] & 7) << 1) |
(mea8000->buf[3] >> 7) ];
mea8000->framelog = fd + 6 /* 64 samples / ms */ + 3;
mea8000->framelength = 1 << mea8000->framelog;
mea8000->bufpos = 0;
#ifdef FLOAT_MODE
LOG(( "mea800_decode_frame: pitch=%i noise=%i fm1=%gHz bw1=%gHz fm2=%gHz bw2=%gHz fm3=%gHz bw3=%gHz fm4=%gHz bw4=%gHz ampl=%g fd=%ims\n",
mea8000->pitch, mea8000->noise,
mea8000->f[0].fm, mea8000->f[0].bw, mea8000->f[1].fm, mea8000->f[1].bw,
mea8000->f[2].fm, mea8000->f[2].bw, mea8000->f[3].fm, mea8000->f[3].bw,
mea8000->ampl/1000., 8 << fd ));
#else
LOG(( "mea800_decode_frame: pitch=%i noise=%i fm1=%iHz bw1=%iHz fm2=%iHz bw2=%iHz fm3=%iHz bw3=%iHz fm4=%iHz bw4=%iHz ampl=%g fd=%ims\n",
mea8000->pitch, mea8000->noise,
mea8000->f[0].fm, mea8000->f[0].bw, mea8000->f[1].fm, mea8000->f[1].bw,
mea8000->f[2].fm, mea8000->f[2].bw, mea8000->f[3].fm, mea8000->f[3].bw,
mea8000->ampl/1000., 8 << fd ));
#endif
}
static void mea8000_start_frame( mea8000_t* mea8000 )
{
/* enter or stay in active mode */
mea8000->timer->reset( SAMPLING );
mea8000->framepos = 0;
}
static void mea8000_stop_frame( running_machine &machine, mea8000_t* mea8000 )
{
/* enter stop mode */
mea8000->timer->reset( );
mea8000->state = MEA8000_STOPPED;
machine.device<dac_device>(mea8000->iface->channel)->write_signed16(0x8000);
}
/* next sample in frame, sampling at 64 kHz */
static TIMER_CALLBACK( mea8000_timer_expire )
{
device_t* device = (device_t*) ptr;
mea8000_t* mea8000 = get_safe_token( device );
int pos = mea8000->framepos % SUPERSAMPLING;
if (!pos)
{
/* sample is really computed only every 8-th time */
mea8000->lastsample = mea8000->sample;
mea8000->sample = mea8000_compute_sample(mea8000);
machine.device<dac_device>(mea8000->iface->channel)->write_signed16(0x8000+mea8000->lastsample);
}
else
{
/* other samples are simply interpolated */
int sample =
mea8000->lastsample +
((pos*(mea8000->sample-mea8000->lastsample)) / SUPERSAMPLING);
machine.device<dac_device>(mea8000->iface->channel)->write_signed16(0x8000+sample);
}
mea8000->framepos++;
if (mea8000->framepos >= mea8000->framelength)
{
mea8000_shift_frame(mea8000);
/* end of frame */
if (mea8000->bufpos == 4)
{
/* we have a successor */
LOG(( "%f mea8000_timer_expire: new frame\n", machine.time().as_double() ));
mea8000_decode_frame(mea8000);
mea8000_start_frame(mea8000);
}
else if (mea8000->cont)
{
/* repeat mode */
LOG(( "%f mea8000_timer_expire: repeat frame\n", machine.time().as_double() ));
mea8000_start_frame(mea8000);
}
/* slow stop */
else if (mea8000->state == MEA8000_STARTED)
{
mea8000->ampl = 0;
LOG(( "%f mea8000_timer_expire: fade frame\n", machine.time().as_double() ));
mea8000_start_frame(mea8000);
mea8000->state = MEA8000_SLOWING;
}
else if (mea8000->state == MEA8000_SLOWING)
{
LOG(( "%f mea8000_timer_expire: stop frame\n", machine.time().as_double() ));
mea8000_stop_frame(machine, mea8000);
}
mea8000_update_req(device);
}
else
{
/* continue frame */
mea8000->timer->reset( SAMPLING );
}
}
/************************** CPU interface ****************************/
READ8_DEVICE_HANDLER ( mea8000_r )
{
mea8000_t* mea8000 = get_safe_token( device );
switch ( offset )
{
case 0: /* status register */
case 1:
/* ready to accept next frame */
#if 0
LOG(( "$%04x %f: mea8000_r ready=%i\n", space.machine().firstcpu->pcbase( ), machine.time().as_double(), mea8000_accept_byte( mea8000 ) ));
#endif
return mea8000_accept_byte(mea8000) << 7;
default:
logerror( "$%04x mea8000_r invalid read offset %i\n", space.machine().firstcpu->pcbase( ), offset );
}
return 0;
}
WRITE8_DEVICE_HANDLER ( mea8000_w )
{
mea8000_t* mea8000 = get_safe_token( device );
switch ( offset )
{
case 0: /* data register */
if (mea8000->state == MEA8000_STOPPED)
{
/* got pitch byte before first frame */
mea8000->pitch = 2 * data;
LOG(( "$%04x %f: mea8000_w pitch %i\n", space.machine().firstcpu->pcbase( ), space.machine().time().as_double(), mea8000->pitch ));
mea8000->state = MEA8000_WAIT_FIRST;
mea8000->bufpos = 0;
}
else if (mea8000->bufpos == 4)
{
/* overflow */
LOG(( "$%04x %f: mea8000_w data overflow %02X\n", space.machine().firstcpu->pcbase( ), space.machine().time().as_double(), data ));
}
else
{
/* enqueue frame byte */
LOG(( "$%04x %f: mea8000_w data %02X in frame pos %i\n", space.machine().firstcpu->pcbase( ), space.machine().time().as_double(),
data, mea8000->bufpos ));
mea8000->buf[mea8000->bufpos] = data;
mea8000->bufpos++;
if (mea8000->bufpos == 4 && mea8000->state == MEA8000_WAIT_FIRST)
{
/* fade-in first frame */
int old_pitch = mea8000->pitch;
mea8000->last_pitch = old_pitch;
mea8000_decode_frame(mea8000);
mea8000_shift_frame(mea8000);
mea8000->last_pitch = old_pitch;
mea8000->ampl = 0;
mea8000_start_frame(mea8000);
mea8000->state = MEA8000_STARTED;
}
}
mea8000_update_req(device);
break;
case 1: /* command register */
{
int stop = (data >> 4) & 1;
if (data & 8)
mea8000->cont = (data >> 2) & 1;
if (data & 2)
mea8000->roe = data & 1;
if (stop)
mea8000_stop_frame(space.machine(), mea8000);
LOG(( "$%04x %f: mea8000_w command %02X stop=%i cont=%i roe=%i\n",
space.machine().firstcpu->pcbase(), space.machine().time().as_double(), data,
stop, mea8000->cont, mea8000->roe ));
mea8000_update_req(device);
break;
}
default:
logerror( "$%04x mea8000_w invalid write offset %i\n", space.machine().firstcpu->pcbase( ), offset );
}
}
/************************ reset *****************************/
static DEVICE_RESET( mea8000 )
{
mea8000_t* mea8000 = get_safe_token( device );
int i;
LOG (( "mea8000_reset\n" ));
mea8000->timer->reset( );
mea8000->phi = 0;
mea8000->cont = 0;
mea8000->roe = 0;
mea8000->state = MEA8000_STOPPED;
mea8000_update_req(device);
for (i=0; i<4; i++)
{
mea8000->f[i].last_output = 0;
mea8000->f[i].output = 0;
}
}
/****************************** start ********************************/
static DEVICE_START( mea8000 )
{
mea8000_t* mea8000 = get_safe_token( device );
int i;
mea8000->iface = (const mea8000_interface*)device->static_config();
mea8000->req_out.resolve(mea8000->iface->req_out_func, *device);
mea8000_init_tables(device->machine());
mea8000->timer = device->machine().scheduler().timer_alloc(FUNC(mea8000_timer_expire), (void*)device );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->state );
state_save_register_item_array( device->machine(), "mea8000", device->tag(), 0, mea8000->buf );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->bufpos );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->cont );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->roe );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->framelength );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->framepos );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->framelog );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->lastsample );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->sample );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->phi );
for (i=0; i<4; i++)
{
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].fm );
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].last_fm );
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].bw );
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].last_bw );
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].output );
state_save_register_item( device->machine(), "mea8000", device->tag(), i, mea8000->f[i].last_output );
}
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->last_ampl );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->ampl );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->last_pitch );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->pitch );
state_save_register_item( device->machine(), "mea8000", device->tag(), 0, mea8000->noise );
}
const device_type MEA8000 = &device_creator<mea8000_device>;
mea8000_device::mea8000_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, MEA8000, "Philips / Signetics MEA 8000 speech synthesizer", tag, owner, clock)
{
m_token = global_alloc_clear(mea8000_t);
}
//-------------------------------------------------
// device_config_complete - perform any
// operations now that the configuration is
// complete
//-------------------------------------------------
void mea8000_device::device_config_complete()
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void mea8000_device::device_start()
{
DEVICE_START_NAME( mea8000 )(this);
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void mea8000_device::device_reset()
{
DEVICE_RESET_NAME( mea8000 )(this);
}