mame/src/emu/sound/ymz280b.c
Michaël Banaan Ananas 4350726b12 add DEVICE_RESET
2011-08-16 10:50:28 +00:00

1007 lines
28 KiB
C

/*
Yamaha YMZ280B driver
by Aaron Giles
YMZ280B 8-Channel PCMD8 PCM/ADPCM Decoder
Features as listed in LSI-4MZ280B3 data sheet:
Voice data stored in external memory can be played back simultaneously for up to eight voices
Voice data format can be selected from 4-bit ADPCM, 8-bit PCM and 16-bit PCM
Control of voice data external memory
Up to 16M bytes of ROM or SRAM (x 8 bits, access time 150ms max) can be connected
Continuous access is possible
Loop playback between selective addresses is possible
Voice data playback frequency control
4-bit ADPCM ................ 0.172 to 44.1kHz in 256 steps
8-bit PCM, 16-bit PCM ...... 0.172 to 88.2kHz in 512 steps
256 steps total level and 16 steps panpot can be set
Voice signal is output in stereo 16-bit 2's complement MSB-first format
*/
#include "emu.h"
#include "ymz280b.h"
#define MAX_SAMPLE_CHUNK 10000
#define MAKE_WAVS 0
#define FRAC_BITS 14
#define FRAC_ONE (1 << FRAC_BITS)
#define FRAC_MASK (FRAC_ONE - 1)
#define INTERNAL_BUFFER_SIZE (1 << 15)
#define INTERNAL_SAMPLE_RATE (chip->master_clock * 2.0)
#if MAKE_WAVS
#include "wavwrite.h"
#endif
/* struct describing a single playing ADPCM voice */
struct YMZ280BVoice
{
UINT8 playing; /* 1 if we are actively playing */
UINT8 keyon; /* 1 if the key is on */
UINT8 looping; /* 1 if looping is enabled */
UINT8 mode; /* current playback mode */
UINT16 fnum; /* frequency */
UINT8 level; /* output level */
UINT8 pan; /* panning */
UINT32 start; /* start address, in nibbles */
UINT32 stop; /* stop address, in nibbles */
UINT32 loop_start; /* loop start address, in nibbles */
UINT32 loop_end; /* loop end address, in nibbles */
UINT32 position; /* current position, in nibbles */
INT32 signal; /* current ADPCM signal */
INT32 step; /* current ADPCM step */
INT32 loop_signal; /* signal at loop start */
INT32 loop_step; /* step at loop start */
UINT32 loop_count; /* number of loops so far */
INT32 output_left; /* output volume (left) */
INT32 output_right; /* output volume (right) */
INT32 output_step; /* step value for frequency conversion */
INT32 output_pos; /* current fractional position */
INT16 last_sample; /* last sample output */
INT16 curr_sample; /* current sample target */
UINT8 irq_schedule; /* 1 if the IRQ state is updated by timer */
};
typedef struct _ymz280b_state ymz280b_state;
struct _ymz280b_state
{
sound_stream * stream; /* which stream are we using */
UINT8 *region_base; /* pointer to the base of the region */
UINT8 current_register; /* currently accessible register */
UINT8 status_register; /* current status register */
UINT8 irq_state; /* current IRQ state */
UINT8 irq_mask; /* current IRQ mask */
UINT8 irq_enable; /* current IRQ enable */
UINT8 keyon_enable; /* key on enable */
double master_clock; /* master clock frequency */
void (*irq_callback)(device_t *, int); /* IRQ callback */
struct YMZ280BVoice voice[8]; /* the 8 voices */
UINT32 rom_readback_addr; /* where the CPU can read the ROM */
devcb_resolved_read8 ext_ram_read; /* external RAM read handler */
devcb_resolved_write8 ext_ram_write; /* external RAM write handler */
#if MAKE_WAVS
void * wavresample; /* resampled waveform */
#endif
INT16 *scratch;
device_t *device;
};
static void write_to_register(ymz280b_state *, int);
/* step size index shift table */
static const int index_scale[8] = { 0x0e6, 0x0e6, 0x0e6, 0x0e6, 0x133, 0x199, 0x200, 0x266 };
/* lookup table for the precomputed difference */
static int diff_lookup[16];
/* timer callback */
static TIMER_CALLBACK( update_irq_state_timer_0 );
static TIMER_CALLBACK( update_irq_state_timer_1 );
static TIMER_CALLBACK( update_irq_state_timer_2 );
static TIMER_CALLBACK( update_irq_state_timer_3 );
static TIMER_CALLBACK( update_irq_state_timer_4 );
static TIMER_CALLBACK( update_irq_state_timer_5 );
static TIMER_CALLBACK( update_irq_state_timer_6 );
static TIMER_CALLBACK( update_irq_state_timer_7 );
static const struct { timer_expired_func func; const char *name; } update_irq_state_cb[] =
{
{ FUNC(update_irq_state_timer_0) },
{ FUNC(update_irq_state_timer_1) },
{ FUNC(update_irq_state_timer_2) },
{ FUNC(update_irq_state_timer_3) },
{ FUNC(update_irq_state_timer_4) },
{ FUNC(update_irq_state_timer_5) },
{ FUNC(update_irq_state_timer_6) },
{ FUNC(update_irq_state_timer_7) }
};
INLINE ymz280b_state *get_safe_token(device_t *device)
{
assert(device != NULL);
assert(device->type() == YMZ280B);
return (ymz280b_state *)downcast<legacy_device_base *>(device)->token();
}
INLINE void update_irq_state(ymz280b_state *chip)
{
int irq_bits = chip->status_register & chip->irq_mask;
/* always off if the enable is off */
if (!chip->irq_enable)
irq_bits = 0;
/* update the state if changed */
if (irq_bits && !chip->irq_state)
{
chip->irq_state = 1;
if (chip->irq_callback)
(*chip->irq_callback)(chip->device, 1);
else logerror("YMZ280B: IRQ generated, but no callback specified!");
}
else if (!irq_bits && chip->irq_state)
{
chip->irq_state = 0;
if (chip->irq_callback)
(*chip->irq_callback)(chip->device, 0);
else logerror("YMZ280B: IRQ generated, but no callback specified!");
}
}
INLINE void update_step(ymz280b_state *chip, struct YMZ280BVoice *voice)
{
double frequency;
/* compute the frequency */
if (voice->mode == 1)
frequency = chip->master_clock * (double)((voice->fnum & 0x0ff) + 1) * (1.0 / 256.0);
else
frequency = chip->master_clock * (double)((voice->fnum & 0x1ff) + 1) * (1.0 / 256.0);
voice->output_step = (UINT32)(frequency * (double)FRAC_ONE / INTERNAL_SAMPLE_RATE);
}
INLINE void update_volumes(struct YMZ280BVoice *voice)
{
if (voice->pan == 8)
{
voice->output_left = voice->level;
voice->output_right = voice->level;
}
else if (voice->pan < 8)
{
voice->output_left = voice->level;
voice->output_right = voice->level * voice->pan / 8;
}
else
{
voice->output_left = voice->level * (15 - voice->pan) / 8;
voice->output_right = voice->level;
}
}
static void YMZ280B_state_save_update_step(ymz280b_state *chip)
{
int j;
for (j = 0; j < 8; j++)
{
struct YMZ280BVoice *voice = &chip->voice[j];
update_step(chip, voice);
if(voice->irq_schedule)
chip->device->machine().scheduler().timer_set(attotime::zero, update_irq_state_cb[j].func, update_irq_state_cb[j].name, 0, chip);
}
}
static void update_irq_state_timer_common(void *param, int voicenum)
{
ymz280b_state *chip = (ymz280b_state *)param;
struct YMZ280BVoice *voice = &chip->voice[voicenum];
if(!voice->irq_schedule) return;
voice->playing = 0;
chip->status_register |= 1 << voicenum;
update_irq_state(chip);
voice->irq_schedule = 0;
}
static TIMER_CALLBACK( update_irq_state_timer_0 ) { update_irq_state_timer_common(ptr, 0); }
static TIMER_CALLBACK( update_irq_state_timer_1 ) { update_irq_state_timer_common(ptr, 1); }
static TIMER_CALLBACK( update_irq_state_timer_2 ) { update_irq_state_timer_common(ptr, 2); }
static TIMER_CALLBACK( update_irq_state_timer_3 ) { update_irq_state_timer_common(ptr, 3); }
static TIMER_CALLBACK( update_irq_state_timer_4 ) { update_irq_state_timer_common(ptr, 4); }
static TIMER_CALLBACK( update_irq_state_timer_5 ) { update_irq_state_timer_common(ptr, 5); }
static TIMER_CALLBACK( update_irq_state_timer_6 ) { update_irq_state_timer_common(ptr, 6); }
static TIMER_CALLBACK( update_irq_state_timer_7 ) { update_irq_state_timer_common(ptr, 7); }
/**********************************************************************************************
compute_tables -- compute the difference tables
***********************************************************************************************/
static void compute_tables(void)
{
int nib;
/* loop over all nibbles and compute the difference */
for (nib = 0; nib < 16; nib++)
{
int value = (nib & 0x07) * 2 + 1;
diff_lookup[nib] = (nib & 0x08) ? -value : value;
}
}
/**********************************************************************************************
generate_adpcm -- general ADPCM decoding routine
***********************************************************************************************/
static int generate_adpcm(struct YMZ280BVoice *voice, UINT8 *base, INT16 *buffer, int samples)
{
int position = voice->position;
int signal = voice->signal;
int step = voice->step;
int val;
/* two cases: first cases is non-looping */
if (!voice->looping)
{
/* loop while we still have samples to generate */
while (samples)
{
/* compute the new amplitude and update the current step */
val = base[position / 2] >> ((~position & 1) << 2);
signal += (step * diff_lookup[val & 15]) / 8;
/* clamp to the maximum */
if (signal > 32767)
signal = 32767;
else if (signal < -32768)
signal = -32768;
/* adjust the step size and clamp */
step = (step * index_scale[val & 7]) >> 8;
if (step > 0x6000)
step = 0x6000;
else if (step < 0x7f)
step = 0x7f;
/* output to the buffer, scaling by the volume */
*buffer++ = signal;
samples--;
/* next! */
position++;
if (position >= voice->stop)
break;
}
}
/* second case: looping */
else
{
/* loop while we still have samples to generate */
while (samples)
{
/* compute the new amplitude and update the current step */
val = base[position / 2] >> ((~position & 1) << 2);
signal += (step * diff_lookup[val & 15]) / 8;
/* clamp to the maximum */
if (signal > 32767)
signal = 32767;
else if (signal < -32768)
signal = -32768;
/* adjust the step size and clamp */
step = (step * index_scale[val & 7]) >> 8;
if (step > 0x6000)
step = 0x6000;
else if (step < 0x7f)
step = 0x7f;
/* output to the buffer, scaling by the volume */
*buffer++ = signal;
samples--;
/* next! */
position++;
if (position == voice->loop_start && voice->loop_count == 0)
{
voice->loop_signal = signal;
voice->loop_step = step;
}
if (position >= voice->loop_end)
{
if (voice->keyon)
{
position = voice->loop_start;
signal = voice->loop_signal;
step = voice->loop_step;
voice->loop_count++;
}
}
if (position >= voice->stop)
break;
}
}
/* update the parameters */
voice->position = position;
voice->signal = signal;
voice->step = step;
return samples;
}
/**********************************************************************************************
generate_pcm8 -- general 8-bit PCM decoding routine
***********************************************************************************************/
static int generate_pcm8(struct YMZ280BVoice *voice, UINT8 *base, INT16 *buffer, int samples)
{
int position = voice->position;
int val;
/* two cases: first cases is non-looping */
if (!voice->looping)
{
/* loop while we still have samples to generate */
while (samples)
{
/* fetch the current value */
val = base[position / 2];
/* output to the buffer, scaling by the volume */
*buffer++ = (INT8)val * 256;
samples--;
/* next! */
position += 2;
if (position >= voice->stop)
break;
}
}
/* second case: looping */
else
{
/* loop while we still have samples to generate */
while (samples)
{
/* fetch the current value */
val = base[position / 2];
/* output to the buffer, scaling by the volume */
*buffer++ = (INT8)val * 256;
samples--;
/* next! */
position += 2;
if (position >= voice->loop_end)
{
if (voice->keyon)
position = voice->loop_start;
}
if (position >= voice->stop)
break;
}
}
/* update the parameters */
voice->position = position;
return samples;
}
/**********************************************************************************************
generate_pcm16 -- general 16-bit PCM decoding routine
***********************************************************************************************/
static int generate_pcm16(struct YMZ280BVoice *voice, UINT8 *base, INT16 *buffer, int samples)
{
int position = voice->position;
int val;
/* two cases: first cases is non-looping */
if (!voice->looping)
{
/* loop while we still have samples to generate */
while (samples)
{
/* fetch the current value */
val = (INT16)((base[position / 2 + 1] << 8) + base[position / 2]);
/* output to the buffer, scaling by the volume */
*buffer++ = val;
samples--;
/* next! */
position += 4;
if (position >= voice->stop)
break;
}
}
/* second case: looping */
else
{
/* loop while we still have samples to generate */
while (samples)
{
/* fetch the current value */
val = (INT16)((base[position / 2 + 1] << 8) + base[position / 2]);
/* output to the buffer, scaling by the volume */
*buffer++ = val;
samples--;
/* next! */
position += 4;
if (position >= voice->loop_end)
{
if (voice->keyon)
position = voice->loop_start;
}
if (position >= voice->stop)
break;
}
}
/* update the parameters */
voice->position = position;
return samples;
}
/**********************************************************************************************
ymz280b_update -- update the sound chip so that it is in sync with CPU execution
***********************************************************************************************/
static STREAM_UPDATE( ymz280b_update )
{
ymz280b_state *chip = (ymz280b_state *)param;
stream_sample_t *lacc = outputs[0];
stream_sample_t *racc = outputs[1];
int v;
/* clear out the accumulator */
memset(lacc, 0, samples * sizeof(lacc[0]));
memset(racc, 0, samples * sizeof(racc[0]));
/* loop over voices */
for (v = 0; v < 8; v++)
{
struct YMZ280BVoice *voice = &chip->voice[v];
INT16 prev = voice->last_sample;
INT16 curr = voice->curr_sample;
INT16 *curr_data = chip->scratch;
INT32 *ldest = lacc;
INT32 *rdest = racc;
UINT32 new_samples, samples_left;
UINT32 final_pos;
int remaining = samples;
int lvol = voice->output_left;
int rvol = voice->output_right;
/* quick out if we're not playing and we're at 0 */
if (!voice->playing && curr == 0)
continue;
/* finish off the current sample */
// if (voice->output_pos > 0)
{
/* interpolate */
while (remaining > 0 && voice->output_pos < FRAC_ONE)
{
int interp_sample = (((INT32)prev * (FRAC_ONE - voice->output_pos)) + ((INT32)curr * voice->output_pos)) >> FRAC_BITS;
*ldest++ += interp_sample * lvol;
*rdest++ += interp_sample * rvol;
voice->output_pos += voice->output_step;
remaining--;
}
/* if we're over, continue; otherwise, we're done */
if (voice->output_pos >= FRAC_ONE)
voice->output_pos -= FRAC_ONE;
else
continue;
}
/* compute how many new samples we need */
final_pos = voice->output_pos + remaining * voice->output_step;
new_samples = (final_pos + FRAC_ONE) >> FRAC_BITS;
if (new_samples > MAX_SAMPLE_CHUNK)
new_samples = MAX_SAMPLE_CHUNK;
samples_left = new_samples;
/* generate them into our buffer */
if (voice->playing)
{
switch (voice->mode)
{
case 1: samples_left = generate_adpcm(voice, chip->region_base, chip->scratch, new_samples); break;
case 2: samples_left = generate_pcm8(voice, chip->region_base, chip->scratch, new_samples); break;
case 3: samples_left = generate_pcm16(voice, chip->region_base, chip->scratch, new_samples); break;
default:
case 0: samples_left = 0; memset(chip->scratch, 0, new_samples * sizeof(chip->scratch[0])); break;
}
}
/* if there are leftovers, ramp back to 0 */
if (samples_left)
{
int base = new_samples - samples_left;
int i, t = (base == 0) ? curr : chip->scratch[base - 1];
for (i = 0; i < samples_left; i++)
{
if (t < 0) t = -((-t * 15) >> 4);
else if (t > 0) t = (t * 15) >> 4;
chip->scratch[base + i] = t;
}
/* if we hit the end and IRQs are enabled, signal it */
if (base != 0)
{
voice->playing = 0;
/* set update_irq_state_timer. IRQ is signaled on next CPU execution. */
chip->device->machine().scheduler().timer_set(attotime::zero, update_irq_state_cb[v].func, update_irq_state_cb[v].name, 0, chip);
voice->irq_schedule = 1;
}
}
/* advance forward one sample */
prev = curr;
curr = *curr_data++;
/* then sample-rate convert with linear interpolation */
while (remaining > 0)
{
/* interpolate */
while (remaining > 0 && voice->output_pos < FRAC_ONE)
{
int interp_sample = (((INT32)prev * (FRAC_ONE - voice->output_pos)) + ((INT32)curr * voice->output_pos)) >> FRAC_BITS;
*ldest++ += interp_sample * lvol;
*rdest++ += interp_sample * rvol;
voice->output_pos += voice->output_step;
remaining--;
}
/* if we're over, grab the next samples */
if (voice->output_pos >= FRAC_ONE)
{
voice->output_pos -= FRAC_ONE;
prev = curr;
curr = *curr_data++;
}
}
/* remember the last samples */
voice->last_sample = prev;
voice->curr_sample = curr;
}
for (v = 0; v < samples; v++)
{
outputs[0][v] /= 256;
outputs[1][v] /= 256;
}
}
/**********************************************************************************************
DEVICE_START/RESET( ymz280b ) -- start/reset emulation of the YMZ280B
***********************************************************************************************/
static DEVICE_START( ymz280b )
{
static const ymz280b_interface defintrf = { 0 };
const ymz280b_interface *intf = (device->static_config() != NULL) ? (const ymz280b_interface *)device->static_config() : &defintrf;
ymz280b_state *chip = get_safe_token(device);
chip->device = device;
chip->ext_ram_read.resolve(intf->ext_read, *device);
chip->ext_ram_write.resolve(intf->ext_write, *device);
/* compute ADPCM tables */
compute_tables();
/* initialize the rest of the structure */
chip->master_clock = (double)device->clock() / 384.0;
chip->region_base = *device->region();
chip->irq_callback = intf->irq_callback;
/* create the stream */
chip->stream = device->machine().sound().stream_alloc(*device, 0, 2, INTERNAL_SAMPLE_RATE, chip, ymz280b_update);
/* allocate memory */
chip->scratch = auto_alloc_array(device->machine(), INT16, MAX_SAMPLE_CHUNK);
/* state save */
{
int j;
device->save_item(NAME(chip->current_register));
device->save_item(NAME(chip->status_register));
device->save_item(NAME(chip->irq_state));
device->save_item(NAME(chip->irq_mask));
device->save_item(NAME(chip->irq_enable));
device->save_item(NAME(chip->keyon_enable));
device->save_item(NAME(chip->rom_readback_addr));
for (j = 0; j < 8; j++)
{
device->save_item(NAME(chip->voice[j].playing), j);
device->save_item(NAME(chip->voice[j].keyon), j);
device->save_item(NAME(chip->voice[j].looping), j);
device->save_item(NAME(chip->voice[j].mode), j);
device->save_item(NAME(chip->voice[j].fnum), j);
device->save_item(NAME(chip->voice[j].level), j);
device->save_item(NAME(chip->voice[j].pan), j);
device->save_item(NAME(chip->voice[j].start), j);
device->save_item(NAME(chip->voice[j].stop), j);
device->save_item(NAME(chip->voice[j].loop_start), j);
device->save_item(NAME(chip->voice[j].loop_end), j);
device->save_item(NAME(chip->voice[j].position), j);
device->save_item(NAME(chip->voice[j].signal), j);
device->save_item(NAME(chip->voice[j].step), j);
device->save_item(NAME(chip->voice[j].loop_signal), j);
device->save_item(NAME(chip->voice[j].loop_step), j);
device->save_item(NAME(chip->voice[j].loop_count), j);
device->save_item(NAME(chip->voice[j].output_left), j);
device->save_item(NAME(chip->voice[j].output_right), j);
device->save_item(NAME(chip->voice[j].output_pos), j);
device->save_item(NAME(chip->voice[j].last_sample), j);
device->save_item(NAME(chip->voice[j].curr_sample), j);
device->save_item(NAME(chip->voice[j].irq_schedule), j);
}
}
device->machine().save().register_postload(save_prepost_delegate(FUNC(YMZ280B_state_save_update_step), chip));
#if MAKE_WAVS
chip->wavresample = wav_open("resamp.wav", INTERNAL_SAMPLE_RATE, 2);
#endif
}
static DEVICE_RESET( ymz280b )
{
int i;
ymz280b_state *chip = get_safe_token(device);
/* initial clear registers */
for (i = 0xff; i >= 0; i--)
{
chip->current_register = 0;
write_to_register(chip, 0);
}
chip->current_register = 0;
chip->status_register = 0;
}
/**********************************************************************************************
write_to_register -- handle a write to the current register
***********************************************************************************************/
static void write_to_register(ymz280b_state *chip, int data)
{
struct YMZ280BVoice *voice;
int i;
/* lower registers follow a pattern */
if (chip->current_register < 0x80)
{
voice = &chip->voice[(chip->current_register >> 2) & 7];
switch (chip->current_register & 0xe3)
{
case 0x00: /* pitch low 8 bits */
voice->fnum = (voice->fnum & 0x100) | (data & 0xff);
update_step(chip, voice);
break;
case 0x01: /* pitch upper 1 bit, loop, key on, mode */
voice->fnum = (voice->fnum & 0xff) | ((data & 0x01) << 8);
voice->looping = (data & 0x10) >> 4;
voice->mode = (data & 0x60) >> 5;
if (!voice->keyon && (data & 0x80) && chip->keyon_enable)
{
voice->playing = 1;
voice->position = voice->start;
voice->signal = voice->loop_signal = 0;
voice->step = voice->loop_step = 0x7f;
voice->loop_count = 0;
/* if update_irq_state_timer is set, cancel it. */
voice->irq_schedule = 0;
}
if (voice->keyon && !(data & 0x80) && !voice->looping)
{
voice->playing = 0;
/* if update_irq_state_timer is set, cancel it. */
voice->irq_schedule = 0;
}
voice->keyon = (data & 0x80) >> 7;
update_step(chip, voice);
break;
case 0x02: /* total level */
voice->level = data;
update_volumes(voice);
break;
case 0x03: /* pan */
voice->pan = data & 0x0f;
update_volumes(voice);
break;
case 0x20: /* start address high */
voice->start = (voice->start & (0x00ffff << 1)) | (data << 17);
break;
case 0x21: /* loop start address high */
voice->loop_start = (voice->loop_start & (0x00ffff << 1)) | (data << 17);
break;
case 0x22: /* loop end address high */
voice->loop_end = (voice->loop_end & (0x00ffff << 1)) | (data << 17);
break;
case 0x23: /* stop address high */
voice->stop = (voice->stop & (0x00ffff << 1)) | (data << 17);
break;
case 0x40: /* start address middle */
voice->start = (voice->start & (0xff00ff << 1)) | (data << 9);
break;
case 0x41: /* loop start address middle */
voice->loop_start = (voice->loop_start & (0xff00ff << 1)) | (data << 9);
break;
case 0x42: /* loop end address middle */
voice->loop_end = (voice->loop_end & (0xff00ff << 1)) | (data << 9);
break;
case 0x43: /* stop address middle */
voice->stop = (voice->stop & (0xff00ff << 1)) | (data << 9);
break;
case 0x60: /* start address low */
voice->start = (voice->start & (0xffff00 << 1)) | (data << 1);
break;
case 0x61: /* loop start address low */
voice->loop_start = (voice->loop_start & (0xffff00 << 1)) | (data << 1);
break;
case 0x62: /* loop end address low */
voice->loop_end = (voice->loop_end & (0xffff00 << 1)) | (data << 1);
break;
case 0x63: /* stop address low */
voice->stop = (voice->stop & (0xffff00 << 1)) | (data << 1);
break;
default:
logerror("YMZ280B: unknown register write %02X = %02X\n", chip->current_register, data);
break;
}
}
/* upper registers are special */
else
{
switch (chip->current_register)
{
/* DSP related (not implemented yet) */
case 0x80: // d0-2: DSP Rch, d3: enable Rch (0: yes, 1: no), d4-6: DSP Lch, d7: enable Lch (0: yes, 1: no)
case 0x81: // d0: enable control of $82 (0: yes, 1: no)
case 0x82: // DSP data
logerror("YMZ280B: DSP register write %02X = %02X\n", chip->current_register, data);
break;
case 0x84: /* ROM readback / RAM write (high) */
chip->rom_readback_addr &= 0xffff;
chip->rom_readback_addr |= (data<<16);
break;
case 0x85: /* ROM readback / RAM write (med) */
chip->rom_readback_addr &= 0xff00ff;
chip->rom_readback_addr |= (data<<8);
break;
case 0x86: /* ROM readback / RAM write (low) */
chip->rom_readback_addr &= 0xffff00;
chip->rom_readback_addr |= data;
break;
case 0x87: /* RAM write */
if (!chip->ext_ram_write.isnull())
chip->ext_ram_write(chip->rom_readback_addr, data);
else
logerror("YMZ280B attempted RAM write to %X\n", chip->rom_readback_addr);
chip->rom_readback_addr = (chip->rom_readback_addr + 1) & 0xffffff;
break;
case 0xfe: /* IRQ mask */
chip->irq_mask = data;
update_irq_state(chip);
break;
case 0xff: /* IRQ enable, test, etc */
chip->irq_enable = (data & 0x10) >> 4;
update_irq_state(chip);
if (chip->keyon_enable && !(data & 0x80))
{
for (i = 0; i < 8; i++)
{
chip->voice[i].playing = 0;
/* if update_irq_state_timer is set, cancel it. */
chip->voice[i].irq_schedule = 0;
}
}
else if (!chip->keyon_enable && (data & 0x80))
{
for (i = 0; i < 8; i++)
{
if (chip->voice[i].keyon && chip->voice[i].looping)
chip->voice[i].playing = 1;
}
}
chip->keyon_enable = (data & 0x80) >> 7;
break;
default:
logerror("YMZ280B: unknown register write %02X = %02X\n", chip->current_register, data);
break;
}
}
}
/**********************************************************************************************
compute_status -- determine the status bits
***********************************************************************************************/
static int compute_status(ymz280b_state *chip)
{
UINT8 result;
/* ROM/RAM readback? */
if (chip->current_register == 0x86)
{
return chip->region_base[chip->rom_readback_addr];
}
/* force an update */
chip->stream->update();
result = chip->status_register;
/* clear the IRQ state */
chip->status_register = 0;
update_irq_state(chip);
return result;
}
/**********************************************************************************************
ymz280b_r/ymz280b_w -- handle external accesses
***********************************************************************************************/
READ8_DEVICE_HANDLER( ymz280b_r )
{
ymz280b_state *chip = get_safe_token(device);
if ((offset & 1) == 0)
{
/* read from external memory */
UINT8 read = chip->ext_ram_read.isnull() ? 0 : chip->ext_ram_read(chip->rom_readback_addr);
chip->rom_readback_addr = (chip->rom_readback_addr + 1) & 0xffffff;
return read;
}
else
return compute_status(chip);
}
WRITE8_DEVICE_HANDLER( ymz280b_w )
{
ymz280b_state *chip = get_safe_token(device);
if ((offset & 1) == 0)
chip->current_register = data;
else
{
/* force an update */
chip->stream->update();
write_to_register(chip, data);
}
}
/**************************************************************************
* Generic get_info
**************************************************************************/
DEVICE_GET_INFO( ymz280b )
{
switch (state)
{
/* --- the following bits of info are returned as 64-bit signed integers --- */
case DEVINFO_INT_TOKEN_BYTES: info->i = sizeof(ymz280b_state); break;
/* --- the following bits of info are returned as pointers to data or functions --- */
case DEVINFO_FCT_START: info->start = DEVICE_START_NAME( ymz280b ); break;
case DEVINFO_FCT_STOP: /* Nothing */ break;
case DEVINFO_FCT_RESET: info->start = DEVICE_RESET_NAME( ymz280b ); break;
/* --- the following bits of info are returned as NULL-terminated strings --- */
case DEVINFO_STR_NAME: strcpy(info->s, "YMZ280B"); break;
case DEVINFO_STR_FAMILY: strcpy(info->s, "Yamaha Wavetable"); 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;
}
}
DEFINE_LEGACY_SOUND_DEVICE(YMZ280B, ymz280b);