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https://github.com/holub/mame
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c6280: optimization for games that have sound disabled
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hap
parent
4565368984
commit
fa360c3324
@ -44,6 +44,14 @@
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void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
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{
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// Fast method if none of the channels are enabled (most Data East arcade games)
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if (!(m_enabled & 0x3f))
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{
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outputs[0].fill(0);
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outputs[1].fill(0);
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return;
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}
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static const u8 scale_tab[16] =
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{
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0x00, 0x03, 0x05, 0x07, 0x09, 0x0b, 0x0d, 0x0f,
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@ -53,24 +61,21 @@ void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_st
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const u8 lmal = scale_tab[(m_balance >> 4) & 0x0f];
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const u8 rmal = scale_tab[(m_balance >> 0) & 0x0f];
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/* Clear buffer */
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outputs[0].fill(0);
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outputs[1].fill(0);
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for (int i = 0; i < outputs[0].samples(); i++)
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{
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s32 lout = 0, rout = 0;
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for (int ch = 0; ch < 6; ch++)
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{
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channel &chan = m_channel[ch];
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/* Only look at enabled channels */
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if (BIT(chan.control, 7))
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// Only look at enabled channels
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if (BIT(m_enabled, ch))
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{
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channel &chan = m_channel[ch];
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const u8 lal = scale_tab[(chan.balance >> 4) & 0x0f];
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const u8 ral = scale_tab[(chan.balance >> 0) & 0x0f];
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const u8 al = chan.control & 0x1f;
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// verified from both patent and manual
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// Verified from both patent and manual
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int vll = (0x1f - lmal) + (0x1f - al) + (0x1f - lal);
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if (vll > 0x1f) vll = 0x1f;
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@ -80,10 +85,10 @@ void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_st
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vll = m_volume_table[vll];
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vlr = m_volume_table[vlr];
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/* Check channel mode */
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// Check channel mode
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if ((ch >= 4) && BIT(chan.noise_control, 7))
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{
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/* Noise mode */
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// Noise mode
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const u32 step = (chan.noise_control & 0x1f) ^ 0x1f;
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const s16 data = BIT(chan.noise_seed, 0) ? 0x1f : 0;
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chan.noise_counter--;
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@ -99,7 +104,7 @@ void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_st
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}
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else if (BIT(chan.control, 6))
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{
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/* DDA mode */
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// DDA mode
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lout += vll * (chan.dda - 16);
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rout += vlr * (chan.dda - 16);
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}
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@ -109,7 +114,7 @@ void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_st
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{
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if (ch == 0)
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{
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/* Waveform mode with LFO */
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// Waveform mode with LFO
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channel &lfo_srcchan = m_channel[1];
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channel &lfo_dstchan = m_channel[0];
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const u16 lfo_step = lfo_srcchan.frequency ? lfo_srcchan.frequency : 0x1000;
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@ -149,7 +154,7 @@ void c6280_device::sound_stream_update(sound_stream &stream, std::vector<read_st
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}
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else
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{
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/* Waveform mode */
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// Waveform mode
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const u32 step = chan.frequency ? chan.frequency : 0x1000;
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const s16 data = chan.waveform[chan.index];
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chan.tick--;
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@ -222,30 +227,30 @@ void c6280_device::c6280_w(offs_t offset, uint8_t data)
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{
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channel &chan = m_channel[m_select];
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/* Update stream */
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// Update stream
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m_stream->update();
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switch (offset & 0x0f)
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{
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case 0x00: /* Channel select */
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case 0x00: // Channel select
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m_select = data & 0x07;
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break;
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case 0x01: /* Global balance */
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m_balance = data;
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case 0x01: // Global balance
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m_balance = data;
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break;
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case 0x02: /* Channel frequency (LSB) */
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case 0x02: // Channel frequency (LSB)
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chan.frequency = (chan.frequency & 0x0f00) | data;
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break;
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case 0x03: /* Channel frequency (MSB) */
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case 0x03: // Channel frequency (MSB)
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chan.frequency = (chan.frequency & 0x00ff) | ((data << 8) & 0x0f00);
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break;
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case 0x04: /* Channel control (key-on, DDA mode, volume) */
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case 0x04: // Channel control (key-on, DDA mode, volume)
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/* 1-to-0 transition of DDA bit resets waveform index */
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// 1-to-0 transition of DDA bit resets waveform index
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if (BIT(chan.control, 6) && BIT(~data, 6))
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{
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chan.index = 0;
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@ -255,13 +260,17 @@ void c6280_device::c6280_w(offs_t offset, uint8_t data)
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chan.tick = chan.frequency;
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}
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chan.control = data;
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// Cache channel enable flag
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m_enabled &= ~(1 << m_select);
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m_enabled |= BIT(data, 7) << m_select;
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break;
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case 0x05: /* Channel balance */
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case 0x05: // Channel balance
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chan.balance = data;
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break;
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case 0x06: /* Channel waveform data */
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case 0x06: // Channel waveform data
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switch (chan.control & 0x40)
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{
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@ -278,15 +287,15 @@ void c6280_device::c6280_w(offs_t offset, uint8_t data)
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break;
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case 0x07: /* Noise control (enable, frequency) */
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case 0x07: // Noise control (enable, frequency)
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chan.noise_control = data;
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break;
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case 0x08: /* LFO frequency */
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case 0x08: // LFO frequency
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m_lfo_frequency = data;
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break;
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case 0x09: /* LFO control (enable, mode) */
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case 0x09: // LFO control (enable, mode)
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m_lfo_control = data;
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break;
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@ -314,11 +323,12 @@ void c6280_device::device_clock_changed()
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void c6280_device::device_start()
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{
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/* Loudest volume level for table */
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// Loudest volume level for table
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double level = 65535.0 / 6.0 / 32.0;
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/* Clear context */
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// Clear context
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m_select = 0;
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m_enabled = 0;
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m_balance = 0;
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m_lfo_frequency = 0;
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m_lfo_control = 0;
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@ -326,8 +336,8 @@ void c6280_device::device_start()
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m_stream = stream_alloc(0, 2, clock());
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/* Make volume table */
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/* PSG has 48dB volume range spread over 32 steps */
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// Make volume table
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// PSG has 48dB volume range spread over 32 steps
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double step = 48.0 / 32.0;
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for (int i = 0; i < 31; i++)
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{
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@ -337,6 +347,7 @@ void c6280_device::device_start()
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m_volume_table[31] = 0;
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save_item(NAME(m_select));
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save_item(NAME(m_enabled));
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save_item(NAME(m_balance));
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save_item(NAME(m_lfo_frequency));
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save_item(NAME(m_lfo_control));
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@ -42,6 +42,7 @@ private:
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// internal state
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sound_stream *m_stream;
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u8 m_select;
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u8 m_enabled;
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u8 m_balance;
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u8 m_lfo_frequency;
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u8 m_lfo_control;
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