static void generate_adpcm(struct okim6295 *chip, struct ADPCMVoice *voice, INT16 *buffer, int samples)
{
/* if this voice is active */
if (voice->playing)
{
UINT8 *base = chip->region_base + chip->bank_offset + voice->base_offset;
int sample = voice->sample;
int count = voice->count;
/* loop while we still have samples to generate */
while (samples)
{
/* compute the new amplitude and update the current step */
int nibble = base[sample / 2] >> (((sample & 1) << 2) ^ 4);
/* output to the buffer, scaling by the volume */
*buffer++ = clock_adpcm(&voice->adpcm, nibble) * voice->volume / 256;
samples--;
/* next! */
if (++sample >= count)
{
voice->playing = 0;
break;
}
}
/* update the parameters */
voice->sample = sample;
}
static STREAM_UPDATE( okim6258_update )
{
okim6258_state *chip = (okim6258_state *)param;
stream_sample_t *buffer = outputs[0];
memset(outputs[0], 0, samples * sizeof(*outputs[0]));
if (chip->status & STATUS_PLAYING)
{
int nibble_shift = chip->nibble_shift;
while (samples)
{
/* Compute the new amplitude and update the current step */
int nibble = (chip->data_in >> nibble_shift) & 0xf;
/* Output to the buffer */
INT16 sample = clock_adpcm(chip, nibble);
nibble_shift ^= 4;
*buffer++ = sample;
samples--;
}
/* Update the parameters */
chip->nibble_shift = nibble_shift;
}
void okim6258_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
stream_sample_t *buffer = outputs[0];
memset(outputs[0], 0, samples * sizeof(*outputs[0]));
if (m_status & STATUS_PLAYING)
{
int nibble_shift = m_nibble_shift;
while (samples)
{
/* Compute the new amplitude and update the current step */
int nibble = (m_data_in >> nibble_shift) & 0xf;
/* Output to the buffer */
INT16 sample = clock_adpcm(nibble);
nibble_shift ^= 4;
*buffer++ = sample;
samples--;
}
/* Update the parameters */
m_nibble_shift = nibble_shift;
}
static void generate_adpcm(okim6376_state *chip, struct ADPCMVoice *voice, INT16 *buffer, int samples,int channel)
{
/* if this voice is active */
if (voice->playing)
{
UINT8 *base = chip->region_base + voice->base_offset;
int sample = voice->sample;
int count = voice->count;
/* loop while we still have samples to generate */
while (samples)
{
int nibble;
if (count == 0)
{
/* get the number of samples to play */
count = (base[sample / 2] & 0x7f) << 1;
/* end of voice marker */
if (count == 0)
{
voice->playing = 0;
break;
}
else
{
/* step past the count byte */
sample += 2;
}
}
/* compute the new amplitude and update the current step */
nibble = base[sample / 2] >> (((sample & 1) << 2) ^ 4);
/* output to the buffer, scaling by the volume */
/* signal in range -4096..4095, volume in range 2..16 => signal * volume / 2 in range -32768..32767 */
*buffer++ = clock_adpcm(voice, nibble) * voice->volume / 2;
++sample;
--count;
--samples;
}
/* update the parameters */
voice->sample = sample;
voice->count = count;
}