diff options
author | 2021-05-31 17:40:16 -0700 | |
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committer | 2021-05-31 17:40:16 -0700 | |
commit | 7b5e54a3dfdaa4865f15a3a2e5d8a3b303fe0a75 (patch) | |
tree | fcf9279e875959381ab8c8fc05fd26d6b82b947e /src/devices | |
parent | 1b25f944f334500cd032ff5dc329d11b22fe1798 (diff) |
bbd: Add support for a continuously-varying frequency to avoid abusing the sound manager.
Diffstat (limited to 'src/devices')
-rw-r--r-- | src/devices/sound/bbd.cpp | 61 | ||||
-rw-r--r-- | src/devices/sound/bbd.h | 20 |
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]; }; |