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author Aaron Giles <aaron@aarongiles.com>2021-05-31 17:40:16 -0700
committer Aaron Giles <aaron@aarongiles.com>2021-05-31 17:40:16 -0700
commit7b5e54a3dfdaa4865f15a3a2e5d8a3b303fe0a75 (patch)
treefcf9279e875959381ab8c8fc05fd26d6b82b947e
parent1b25f944f334500cd032ff5dc329d11b22fe1798 (diff)
bbd: Add support for a continuously-varying frequency to avoid abusing the sound manager.
-rw-r--r--src/devices/sound/bbd.cpp61
-rw-r--r--src/devices/sound/bbd.h20
2 files changed, 70 insertions, 11 deletions
diff --git a/src/devices/sound/bbd.cpp b/src/devices/sound/bbd.cpp
index d19a56d9084..e270108b04e 100644
--- a/src/devices/sound/bbd.cpp
+++ b/src/devices/sound/bbd.cpp
@@ -17,7 +17,9 @@ bbd_device_base<Entries, Outputs>::bbd_device_base(const machine_config &mconfig
device_t(mconfig, type, tag, owner, clock),
device_sound_interface(mconfig, *this),
m_stream(nullptr),
- m_curpos(0)
+ m_curpos(0),
+ m_cv_handler(*this),
+ m_next_bbdtime(attotime::zero)
{
std::fill_n(&m_buffer[0], Entries, 0);
}
@@ -30,8 +32,16 @@ bbd_device_base<Entries, Outputs>::bbd_device_base(const machine_config &mconfig
template<int Entries, int Outputs>
void bbd_device_base<Entries, Outputs>::device_start()
{
- m_stream = stream_alloc(1, Outputs, sample_rate());
+ m_cv_handler.resolve();
+
+ if (m_cv_handler.isnull())
+ m_stream = stream_alloc(1, Outputs, sample_rate());
+ else
+ m_stream = stream_alloc(1, Outputs, SAMPLE_RATE_OUTPUT_ADAPTIVE, STREAM_DISABLE_INPUT_RESAMPLING);
+
save_item(NAME(m_buffer));
+ save_item(NAME(m_curpos));
+ save_item(NAME(m_next_bbdtime));
}
@@ -56,12 +66,49 @@ void bbd_device_base<Entries, Outputs>::sound_stream_update(sound_stream &stream
// BBDs that I've seen so far typically have 2 outputs, with the first outputting
// sample n-1 and the second outputting sampe n; if chips with more outputs
// or other taps turn up, this logic will need to be made more flexible
- for (int sampindex = 0; sampindex < outputs[0].samples(); sampindex++)
+ if (m_cv_handler.isnull())
+ {
+ for (int sampindex = 0; sampindex < outputs[0].samples(); sampindex++)
+ {
+ for (int outnum = 0; outnum < Outputs; outnum++)
+ outputs[outnum].put(sampindex, m_buffer[(m_curpos + (Outputs - 1) - outnum) % Entries]);
+ m_buffer[m_curpos] = inputs[0].get(sampindex);
+ m_curpos = (m_curpos + 1) % Entries;
+ }
+ }
+ else
{
- for (int outnum = 0; outnum < Outputs; outnum++)
- outputs[outnum].put(sampindex, m_buffer[(m_curpos + (Outputs - 1) - outnum) % Entries]);
- m_buffer[m_curpos] = inputs[0].get(sampindex);
- m_curpos = (m_curpos + 1) % Entries;
+ read_stream_view in(inputs[0], m_next_bbdtime);
+ attotime intime = in.start_time();
+ attotime outtime = outputs[0].start_time();
+ int inpos = 0;
+
+ // loop until all outputs generated
+ for (int sampindex = 0; sampindex < outputs[0].samples(); sampindex++)
+ {
+ // we need to process some more BBD input
+ while (outtime >= m_next_bbdtime)
+ {
+ // find the input sample that overlaps our start time
+ while (intime + in.sample_period() < m_next_bbdtime)
+ {
+ inpos++;
+ intime += in.sample_period();
+ }
+
+ // copy that to the buffer
+ m_buffer[m_curpos] = in.get(inpos);
+ m_curpos = (m_curpos + 1) % std::size(m_buffer);
+
+ // advance the end time of this BBD sample
+ m_next_bbdtime += attotime(0, m_cv_handler(m_next_bbdtime));
+ }
+
+ // copy the most recently-generated BBD data
+ for (int outnum = 0; outnum < Outputs; outnum++)
+ outputs[outnum].put(sampindex, outputval(outnum - (Outputs - 1)));
+ outtime += outputs[0].sample_period();
+ }
}
}
diff --git a/src/devices/sound/bbd.h b/src/devices/sound/bbd.h
index 799fae790c1..aa307d283c2 100644
--- a/src/devices/sound/bbd.h
+++ b/src/devices/sound/bbd.h
@@ -14,13 +14,19 @@
template<int Entries, int Outputs>
class bbd_device_base : public device_t, public device_sound_interface
{
+public:
+ // configuration
+ template <typename... T> void set_cv_handler(T &&... args)
+ {
+ m_cv_handler.set(std::forward<T>(args)...);
+ }
+
protected:
+ using cv_delegate = device_delegate<attoseconds_t (attotime const &)>;
+
// internal constructor
bbd_device_base(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock, device_type type);
- // override to convert clock to sample rate
- virtual u32 sample_rate() const { return clock(); }
-
// device-level overrides
virtual void device_start() override;
virtual void device_clock_changed() override;
@@ -29,9 +35,15 @@ protected:
virtual void sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs) override;
protected:
+ // override to convert clock to sample rate
+ stream_buffer::sample_t outputval(s32 index) const { return m_buffer[m_curpos + Entries + index]; }
+ virtual u32 sample_rate() const { return clock(); }
+
sound_stream * m_stream;
u32 m_curpos;
- stream_buffer::sample_t m_buffer[Entries];
+ cv_delegate m_cv_handler;
+ attotime m_next_bbdtime;
+ stream_buffer::sample_t m_buffer[Entries + 1];
};