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ay8910.cpp: Reduce performance when expanded mode is enable (#7259)

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cam900 2020-09-22 02:50:57 +09:00 committed by GitHub
parent 57cbc60c78
commit 68bccf67fa
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1 changed files with 9 additions and 10 deletions
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19
src/devices/sound/ay8910.cpp
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@ -1108,12 +1108,13 @@ void ay8910_device::sound_stream_update(sound_stream &stream, std::vector<read_s
for (int chan = 0; chan < NUM_CHANNELS; chan++)
{
tone = &m_tone[chan];
tone->count++;
if (tone->count >= tone->period)
const int period = std::max<int>(1,tone->period);
tone->count += is_expanded_mode() ? 16 : 1;
while (tone->count >= period)
{
tone->duty_cycle = (tone->duty_cycle - 1) & 0x1f;
tone->output = (m_feature & PSG_HAS_EXPANDED_MODE) ? BIT(duty_cycle[tone_duty(tone)], tone->duty_cycle) : BIT(tone->duty_cycle, 0);
tone->count = 0;
tone->output = is_expanded_mode() ? BIT(duty_cycle[tone_duty(tone)], tone->duty_cycle) : BIT(tone->duty_cycle, 0);
tone->count -= period;
}
}
@ -1134,7 +1135,7 @@ void ay8910_device::sound_stream_update(sound_stream &stream, std::vector<read_s
// TODO : get actually algorithm for AY8930
m_rng ^= (((m_rng & 1) ^ ((m_rng >> 3) & 1)) << 17);
m_rng >>= 1;
m_prescale_noise = (m_feature & PSG_HAS_EXPANDED_MODE) ? 16 : 1;
m_prescale_noise = 1;
}
m_prescale_noise--;
}
@ -1336,7 +1337,7 @@ void ay8910_device::device_start()
/* The envelope is pacing twice as fast for the YM2149 as for the AY-3-8910, */
/* This handled by the step parameter. Consequently we use a multipler of 2 here. */
m_channel = stream_alloc(0, m_streams, (m_feature & PSG_HAS_EXPANDED_MODE) ? master_clock * 2 : master_clock / 8);
m_channel = stream_alloc(0, m_streams, master_clock / 8);
ay_set_clock(master_clock);
ay8910_statesave();
@ -1389,9 +1390,9 @@ void ay8910_device::ay_set_clock(int clock)
{
// FIXME: this doesn't belong here, it should be an input pin exposed via devcb
if (((m_feature & PSG_PIN26_IS_CLKSEL) && (m_flags & YM2149_PIN26_LOW)) || (m_feature & PSG_HAS_INTERNAL_DIVIDER))
m_channel->set_sample_rate((m_feature & PSG_HAS_EXPANDED_MODE) ? clock : clock / 16);
m_channel->set_sample_rate(clock / 16);
else
m_channel->set_sample_rate((m_feature & PSG_HAS_EXPANDED_MODE) ? clock * 2 : clock / 8);
m_channel->set_sample_rate(clock / 8);
}
void ay8910_device::device_clock_changed()
@ -1659,8 +1660,6 @@ void ay8910_device::set_type(psg_type_t psg_type)
m_par = &ym2149_param;
m_par_env = &ym2149_param_env;
}
if (m_feature & PSG_HAS_EXPANDED_MODE)
m_step *= 16;
}
DEFINE_DEVICE_TYPE(AY8912, ay8912_device, "ay8912", "AY-3-8912A PSG")