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ym2151: Support dynamic changes to clock frequency

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This commit is contained in:
AJR 2017-06-26 09:12:43 -04:00
parent 44c3a6b25b
commit d1f6b7a719
2 changed files with 23 additions and 12 deletions
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33
src/devices/sound/ym2151.cpp
View File

@ -382,18 +382,6 @@ void ym2151_device::init_tables()
}
}
/* calculate timers' deltas */
for (int i=0; i<1024; i++)
{
/* ASG 980324: changed to compute both tim_A_tab and timer_A_time */
timer_A_time[i] = attotime::from_hz(clock()) * (64 * (1024 - i));
}
for (int i=0; i<256; i++)
{
/* ASG 980324: changed to compute both tim_B_tab and timer_B_time */
timer_B_time[i] = attotime::from_hz(clock()) * (1024 * (256 - i));
}
/* calculate noise periods table */
for (int i=0; i<32; i++)
{
@ -404,6 +392,21 @@ void ym2151_device::init_tables()
}
}
void ym2151_device::calculate_timers()
{
/* calculate timers' deltas */
for (int i=0; i<1024; i++)
{
/* ASG 980324: changed to compute both tim_A_tab and timer_A_time */
timer_A_time[i] = clocks_to_attotime(64 * (1024 - i));
}
for (int i=0; i<256; i++)
{
/* ASG 980324: changed to compute both tim_B_tab and timer_B_time */
timer_B_time[i] = clocks_to_attotime(1024 * (256 - i));
}
}
void ym2151_device::YM2151Operator::key_on(uint32_t key_set, uint32_t eg_cnt)
{
if (!key)
@ -1020,6 +1023,12 @@ void ym2151_device::device_start()
save_item(NAME(connect));
}
void ym2151_device::device_clock_changed()
{
m_stream->set_sample_rate(clock() / 64);
calculate_timers();
}
int ym2151_device::op_calc(YM2151Operator * OP, unsigned int env, signed int pm)
{

2
src/devices/sound/ym2151.h
View File

@ -81,6 +81,7 @@ protected:
virtual void device_reset() override;
virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
virtual void device_post_load() override;
virtual void device_clock_changed() override;
// sound stream update overrides
virtual void sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) override;
@ -259,6 +260,7 @@ private:
devcb_write8 m_portwritehandler;
void init_tables();
void calculate_timers();
void envelope_KONKOFF(YM2151Operator * op, int v);
void set_connect(YM2151Operator *om1, int cha, int v);
void advance();