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Diffstat (limited to '3rdparty/ymfm/src/ymfm_pcm.cpp')
-rw-r--r-- | 3rdparty/ymfm/src/ymfm_pcm.cpp | 712 |
1 files changed, 712 insertions, 0 deletions
diff --git a/3rdparty/ymfm/src/ymfm_pcm.cpp b/3rdparty/ymfm/src/ymfm_pcm.cpp new file mode 100644 index 00000000000..3acd59e2a4d --- /dev/null +++ b/3rdparty/ymfm/src/ymfm_pcm.cpp @@ -0,0 +1,712 @@ +// BSD 3-Clause License +// +// Copyright (c) 2021, Aaron Giles +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this +// list of conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "ymfm_pcm.h" +#include "ymfm_fm.h" +#include "ymfm_fm.ipp" + +namespace ymfm +{ + +//********************************************************* +// PCM REGISTERS +//********************************************************* + +//------------------------------------------------- +// reset - reset the register state +//------------------------------------------------- + +void pcm_registers::reset() +{ + std::fill_n(&m_regdata[0], REGISTERS, 0); + m_regdata[0x02] = 0x20; + m_regdata[0xf8] = 0x1b; +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void pcm_registers::save_restore(ymfm_saved_state &state) +{ + state.save_restore(m_regdata); +} + + +//------------------------------------------------- +// cache_channel_data - update the cache with +// data from the registers +//------------------------------------------------- + +void pcm_registers::cache_channel_data(uint32_t choffs, pcm_cache &cache) +{ + // compute step from octave and fnumber; the math here implies + // a .18 fraction but .16 should be perfectly fine + int32_t octave = int8_t(ch_octave(choffs) << 4) >> 4; + uint32_t fnum = ch_fnumber(choffs); + cache.step = ((0x400 | fnum) << (octave + 7)) >> 2; + + // total level is computed as a .10 value for interpolation + cache.total_level = ch_total_level(choffs) << 10; + + // compute panning values in terms of envelope attenuation + int32_t panpot = int8_t(ch_panpot(choffs) << 4) >> 4; + if (panpot >= 0) + { + cache.pan_left = (panpot == 7) ? 0x3ff : 0x20 * panpot; + cache.pan_right = 0; + } + else if (panpot >= -7) + { + cache.pan_left = 0; + cache.pan_right = (panpot == -7) ? 0x3ff : -0x20 * panpot; + } + else + cache.pan_left = cache.pan_right = 0x3ff; + + // determine the LFO stepping value; this how much to add to a running + // x.18 value for the LFO; steps were derived from frequencies in the + // manual and come out very close with these values + static const uint8_t s_lfo_steps[8] = { 1, 12, 19, 25, 31, 35, 37, 42 }; + cache.lfo_step = s_lfo_steps[ch_lfo_speed(choffs)]; + + // AM LFO depth values, derived from the manual; note each has at most + // 2 bits to make the "multiply" easy in hardware + static const uint8_t s_am_depth[8] = { 0, 0x14, 0x20, 0x28, 0x30, 0x40, 0x50, 0x80 }; + cache.am_depth = s_am_depth[ch_am_depth(choffs)]; + + // PM LFO depth values; these are converted from the manual's cents values + // into f-numbers; the computations come out quite cleanly so pretty sure + // these are correct + static const uint8_t s_pm_depth[8] = { 0, 2, 3, 4, 6, 12, 24, 48 }; + cache.pm_depth = s_pm_depth[ch_vibrato(choffs)]; + + // 4-bit sustain level, but 15 means 31 so effectively 5 bits + cache.eg_sustain = ch_sustain_level(choffs); + cache.eg_sustain |= (cache.eg_sustain + 1) & 0x10; + cache.eg_sustain <<= 5; + + // compute the key scaling correction factor; 15 means don't do any correction + int32_t correction = ch_rate_correction(choffs); + if (correction == 15) + correction = 0; + else + correction = (octave + correction) * 2 + bitfield(fnum, 9); + + // compute the envelope generator rates + cache.eg_rate[EG_ATTACK] = effective_rate(ch_attack_rate(choffs), correction); + cache.eg_rate[EG_DECAY] = effective_rate(ch_decay_rate(choffs), correction); + cache.eg_rate[EG_SUSTAIN] = effective_rate(ch_sustain_rate(choffs), correction); + cache.eg_rate[EG_RELEASE] = effective_rate(ch_release_rate(choffs), correction); + cache.eg_rate[EG_REVERB] = 5; + + // if damping is on, override some things; essentially decay at a hardcoded + // rate of 48 until -12db (0x80), then at maximum rate for the rest + if (ch_damp(choffs) != 0) + { + cache.eg_rate[EG_DECAY] = 48; + cache.eg_rate[EG_SUSTAIN] = 63; + cache.eg_rate[EG_RELEASE] = 63; + cache.eg_sustain = 0x80; + } +} + + +//------------------------------------------------- +// effective_rate - return the effective rate, +// clamping and applying corrections as needed +//------------------------------------------------- + +uint32_t pcm_registers::effective_rate(uint32_t raw, uint32_t correction) +{ + // raw rates of 0 and 15 just pin to min/max + if (raw == 0) + return 0; + if (raw == 15) + return 63; + + // otherwise add the correction and clamp to range + return clamp(raw * 4 + correction, 0, 63); +} + + + +//********************************************************* +// PCM CHANNEL +//********************************************************* + +//------------------------------------------------- +// pcm_channel - constructor +//------------------------------------------------- + +pcm_channel::pcm_channel(pcm_engine &owner, uint32_t choffs) : + m_choffs(choffs), + m_baseaddr(0), + m_endpos(0), + m_looppos(0), + m_curpos(0), + m_nextpos(0), + m_lfo_counter(0), + m_eg_state(EG_RELEASE), + m_env_attenuation(0x3ff), + m_total_level(0x7f << 10), + m_format(0), + m_key_state(0), + m_regs(owner.regs()), + m_owner(owner) +{ +} + + +//------------------------------------------------- +// reset - reset the channel state +//------------------------------------------------- + +void pcm_channel::reset() +{ + m_baseaddr = 0; + m_endpos = 0; + m_looppos = 0; + m_curpos = 0; + m_nextpos = 0; + m_lfo_counter = 0; + m_eg_state = EG_RELEASE; + m_env_attenuation = 0x3ff; + m_total_level = 0x7f << 10; + m_format = 0; + m_key_state = 0; +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void pcm_channel::save_restore(ymfm_saved_state &state) +{ + state.save_restore(m_baseaddr); + state.save_restore(m_endpos); + state.save_restore(m_looppos); + state.save_restore(m_curpos); + state.save_restore(m_nextpos); + state.save_restore(m_lfo_counter); + state.save_restore(m_eg_state); + state.save_restore(m_env_attenuation); + state.save_restore(m_total_level); + state.save_restore(m_format); + state.save_restore(m_key_state); +} + + +//------------------------------------------------- +// prepare - prepare for clocking +//------------------------------------------------- + +bool pcm_channel::prepare() +{ + // cache the data + m_regs.cache_channel_data(m_choffs, m_cache); + + // clock the key state + if ((m_key_state & KEY_PENDING) != 0) + { + uint8_t oldstate = m_key_state; + m_key_state = (m_key_state >> 1) & KEY_ON; + if (((oldstate ^ m_key_state) & KEY_ON) != 0) + { + if ((m_key_state & KEY_ON) != 0) + start_attack(); + else + start_release(); + } + } + + // set the total level directly if not interpolating + if (m_regs.ch_level_direct(m_choffs)) + m_total_level = m_cache.total_level; + + // we're active until we're quiet after the release + return (m_eg_state < EG_RELEASE || m_env_attenuation < EG_QUIET); +} + + +//------------------------------------------------- +// clock - master clocking function +//------------------------------------------------- + +void pcm_channel::clock(uint32_t env_counter) +{ + // clock the LFO, which is an x.18 value incremented based on the + // LFO speed value + m_lfo_counter += m_cache.lfo_step; + + // clock the envelope + clock_envelope(env_counter); + + // determine the step after applying vibrato + uint32_t step = m_cache.step; + if (m_cache.pm_depth != 0) + { + // shift the LFO by 1/4 cycle for PM so that it starts at 0 + uint32_t lfo_shifted = m_lfo_counter + (1 << 16); + int32_t lfo_value = bitfield(lfo_shifted, 10, 7); + if (bitfield(lfo_shifted, 17) != 0) + lfo_value ^= 0x7f; + lfo_value -= 0x40; + step += (lfo_value * int32_t(m_cache.pm_depth)) >> 7; + } + + // advance the sample step and loop as needed + m_curpos = m_nextpos; + m_nextpos = m_curpos + step; + if (m_nextpos >= m_endpos) + m_nextpos += m_looppos - m_endpos; + + // interpolate total level if needed + if (m_total_level != m_cache.total_level) + { + // max->min volume takes 156.4ms, or pretty close to 19/1024 per 44.1kHz sample + // min->max volume is half that, so advance by 38/1024 per sample + if (m_total_level < m_cache.total_level) + m_total_level = std::min<int32_t>(m_total_level + 19, m_cache.total_level); + else + m_total_level = std::max<int32_t>(m_total_level - 38, m_cache.total_level); + } +} + + +//------------------------------------------------- +// output - return the computed output value, with +// panning applied +//------------------------------------------------- + +void pcm_channel::output(output_data &output) const +{ + // early out if the envelope is effectively off + uint32_t envelope = m_env_attenuation; + if (envelope > EG_QUIET) + return; + + // add in LFO AM modulation + if (m_cache.am_depth != 0) + { + uint32_t lfo_value = bitfield(m_lfo_counter, 10, 7); + if (bitfield(m_lfo_counter, 17) != 0) + lfo_value ^= 0x7f; + envelope += (lfo_value * m_cache.am_depth) >> 7; + } + + // add in the current interpolated total level value, which is a .10 + // value shifted left by 2 + envelope += m_total_level >> 8; + + // add in panning effect and clamp + uint32_t lenv = std::min<uint32_t>(envelope + m_cache.pan_left, 0x3ff); + uint32_t renv = std::min<uint32_t>(envelope + m_cache.pan_right, 0x3ff); + + // convert to volume as a .11 fraction + int32_t lvol = attenuation_to_volume(lenv << 2); + int32_t rvol = attenuation_to_volume(renv << 2); + + // fetch current sample and add + int16_t sample = fetch_sample(); + uint32_t outnum = m_regs.ch_output_channel(m_choffs) * 2; + output.data[outnum + 0] += (lvol * sample) >> 15; + output.data[outnum + 1] += (rvol * sample) >> 15; +} + + +//------------------------------------------------- +// keyonoff - signal key on/off +//------------------------------------------------- + +void pcm_channel::keyonoff(bool on) +{ + // mark the key state as pending + m_key_state |= KEY_PENDING | (on ? KEY_PENDING_ON : 0); + + // don't log masked channels + if ((m_key_state & (KEY_PENDING_ON | KEY_ON)) == KEY_PENDING_ON && ((debug::GLOBAL_PCM_CHANNEL_MASK >> m_choffs) & 1) != 0) + { + debug::log_keyon("KeyOn PCM-%02d: num=%3d oct=%2d fnum=%03X level=%02X%c ADSR=%X/%X/%X/%X SL=%X", + m_choffs, + m_regs.ch_wave_table_num(m_choffs), + int8_t(m_regs.ch_octave(m_choffs) << 4) >> 4, + m_regs.ch_fnumber(m_choffs), + m_regs.ch_total_level(m_choffs), + m_regs.ch_level_direct(m_choffs) ? '!' : '/', + m_regs.ch_attack_rate(m_choffs), + m_regs.ch_decay_rate(m_choffs), + m_regs.ch_sustain_rate(m_choffs), + m_regs.ch_release_rate(m_choffs), + m_regs.ch_sustain_level(m_choffs)); + + if (m_regs.ch_rate_correction(m_choffs) != 15) + debug::log_keyon(" RC=%X", m_regs.ch_rate_correction(m_choffs)); + + if (m_regs.ch_pseudo_reverb(m_choffs) != 0) + debug::log_keyon(" %s", "REV"); + if (m_regs.ch_damp(m_choffs) != 0) + debug::log_keyon(" %s", "DAMP"); + + if (m_regs.ch_vibrato(m_choffs) != 0 || m_regs.ch_am_depth(m_choffs) != 0) + { + if (m_regs.ch_vibrato(m_choffs) != 0) + debug::log_keyon(" VIB=%d", m_regs.ch_vibrato(m_choffs)); + if (m_regs.ch_am_depth(m_choffs) != 0) + debug::log_keyon(" AM=%d", m_regs.ch_am_depth(m_choffs)); + debug::log_keyon(" LFO=%d", m_regs.ch_lfo_speed(m_choffs)); + } + debug::log_keyon("%s", "\n"); + } +} + + +//------------------------------------------------- +// load_wavetable - load a wavetable by fetching +// its data from external memory +//------------------------------------------------- + +void pcm_channel::load_wavetable() +{ + // determine the address of the wave table header + uint32_t wavnum = m_regs.ch_wave_table_num(m_choffs); + uint32_t wavheader = 12 * wavnum; + + // above 384 it may be in a different bank + if (wavnum >= 384) + { + uint32_t bank = m_regs.wave_table_header(); + if (bank != 0) + wavheader = 512*1024 * bank + (wavnum - 384) * 12; + } + + // fetch the 22-bit base address and 2-bit format + uint8_t byte = read_pcm(wavheader + 0); + m_format = bitfield(byte, 6, 2); + m_baseaddr = bitfield(byte, 0, 6) << 16; + m_baseaddr |= read_pcm(wavheader + 1) << 8; + m_baseaddr |= read_pcm(wavheader + 2) << 0; + + // fetch the 16-bit loop position + m_looppos = read_pcm(wavheader + 3) << 8; + m_looppos |= read_pcm(wavheader + 4); + m_looppos <<= 16; + + // fetch the 16-bit end position, which is stored as a negative value + // for some reason that is unclear + m_endpos = read_pcm(wavheader + 5) << 8; + m_endpos |= read_pcm(wavheader + 6); + m_endpos = -m_endpos << 16; + + // remaining data values set registers + m_owner.write(0x80 + m_choffs, read_pcm(wavheader + 7)); + m_owner.write(0x98 + m_choffs, read_pcm(wavheader + 8)); + m_owner.write(0xb0 + m_choffs, read_pcm(wavheader + 9)); + m_owner.write(0xc8 + m_choffs, read_pcm(wavheader + 10)); + m_owner.write(0xe0 + m_choffs, read_pcm(wavheader + 11)); +} + + +//------------------------------------------------- +// read_pcm - read a byte from the external PCM +// memory interface +//------------------------------------------------- + +uint8_t pcm_channel::read_pcm(uint32_t address) const +{ + return m_owner.intf().ymfm_external_read(ACCESS_PCM, address); +} + + +//------------------------------------------------- +// start_attack - start the attack phase +//------------------------------------------------- + +void pcm_channel::start_attack() +{ + // don't change anything if already in attack state + if (m_eg_state == EG_ATTACK) + return; + m_eg_state = EG_ATTACK; + + // reset the LFO if requested + if (m_regs.ch_lfo_reset(m_choffs)) + m_lfo_counter = 0; + + // if the attack rate == 63 then immediately go to max attenuation + if (m_cache.eg_rate[EG_ATTACK] == 63) + m_env_attenuation = 0; + + // reset the positions + m_curpos = m_nextpos = 0; +} + + +//------------------------------------------------- +// start_release - start the release phase +//------------------------------------------------- + +void pcm_channel::start_release() +{ + // don't change anything if already in release or reverb state + if (m_eg_state >= EG_RELEASE) + return; + m_eg_state = EG_RELEASE; +} + + +//------------------------------------------------- +// clock_envelope - clock the envelope generator +//------------------------------------------------- + +void pcm_channel::clock_envelope(uint32_t env_counter) +{ + // handle attack->decay transitions + if (m_eg_state == EG_ATTACK && m_env_attenuation == 0) + m_eg_state = EG_DECAY; + + // handle decay->sustain transitions + if (m_eg_state == EG_DECAY && m_env_attenuation >= m_cache.eg_sustain) + m_eg_state = EG_SUSTAIN; + + // fetch the appropriate 6-bit rate value from the cache + uint32_t rate = m_cache.eg_rate[m_eg_state]; + + // compute the rate shift value; this is the shift needed to + // apply to the env_counter such that it becomes a 5.11 fixed + // point number + uint32_t rate_shift = rate >> 2; + env_counter <<= rate_shift; + + // see if the fractional part is 0; if not, it's not time to clock + if (bitfield(env_counter, 0, 11) != 0) + return; + + // determine the increment based on the non-fractional part of env_counter + uint32_t relevant_bits = bitfield(env_counter, (rate_shift <= 11) ? 11 : rate_shift, 3); + uint32_t increment = attenuation_increment(rate, relevant_bits); + + // attack is the only one that increases + if (m_eg_state == EG_ATTACK) + m_env_attenuation += (~m_env_attenuation * increment) >> 4; + + // all other cases are similar + else + { + // apply the increment + m_env_attenuation += increment; + + // clamp the final attenuation + if (m_env_attenuation >= 0x400) + m_env_attenuation = 0x3ff; + + // transition to reverb at -18dB if enabled + if (m_env_attenuation >= 0xc0 && m_eg_state < EG_REVERB && m_regs.ch_pseudo_reverb(m_choffs)) + m_eg_state = EG_REVERB; + } +} + + +//------------------------------------------------- +// fetch_sample - fetch a sample at the current +// position +//------------------------------------------------- + +int16_t pcm_channel::fetch_sample() const +{ + uint32_t addr = m_baseaddr; + uint32_t pos = m_curpos >> 16; + + // 8-bit PCM: shift up by 8 + if (m_format == 0) + return read_pcm(addr + pos) << 8; + + // 16-bit PCM: assemble from 2 halves + if (m_format == 2) + { + addr += pos * 2; + return (read_pcm(addr) << 8) | read_pcm(addr + 1); + } + + // 12-bit PCM: assemble out of half of 3 bytes + addr += (pos / 2) * 3; + if ((pos & 1) == 0) + return (read_pcm(addr + 0) << 8) | ((read_pcm(addr + 1) << 0) & 0xf0); + else + return (read_pcm(addr + 2) << 8) | ((read_pcm(addr + 1) << 4) & 0xf0); +} + + + +//********************************************************* +// PCM ENGINE +//********************************************************* + +//------------------------------------------------- +// pcm_engine - constructor +//------------------------------------------------- + +pcm_engine::pcm_engine(ymfm_interface &intf) : + m_intf(intf), + m_env_counter(0), + m_modified_channels(ALL_CHANNELS), + m_active_channels(ALL_CHANNELS) +{ + // create the channels + for (int chnum = 0; chnum < CHANNELS; chnum++) + m_channel[chnum] = std::make_unique<pcm_channel>(*this, chnum); +} + + +//------------------------------------------------- +// reset - reset the engine state +//------------------------------------------------- + +void pcm_engine::reset() +{ + // reset register state + m_regs.reset(); + + // reset each channel + for (auto &chan : m_channel) + chan->reset(); +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void pcm_engine::save_restore(ymfm_saved_state &state) +{ + // save our data + state.save_restore(m_env_counter); + + // save channel state + for (int chnum = 0; chnum < CHANNELS; chnum++) + m_channel[chnum]->save_restore(state); +} + + +//------------------------------------------------- +// clock - master clocking function +//------------------------------------------------- + +void pcm_engine::clock(uint32_t chanmask) +{ + // if something was modified, prepare + // also prepare every 4k samples to catch ending notes + if (m_modified_channels != 0 || m_prepare_count++ >= 4096) + { + // call each channel to prepare + m_active_channels = 0; + for (int chnum = 0; chnum < CHANNELS; chnum++) + if (bitfield(chanmask, chnum)) + if (m_channel[chnum]->prepare()) + m_active_channels |= 1 << chnum; + + // reset the modified channels and prepare count + m_modified_channels = m_prepare_count = 0; + } + + // increment the envelope counter; the envelope generator + // only clocks every other sample in order to make the PCM + // envelopes line up with the FM envelopes (after taking into + // account the different FM sampling rate) + m_env_counter++; + + // now update the state of all the channels and operators + for (int chnum = 0; chnum < CHANNELS; chnum++) + if (bitfield(chanmask, chnum)) + m_channel[chnum]->clock(m_env_counter >> 1); +} + + +//------------------------------------------------- +// update - master update function +//------------------------------------------------- + +void pcm_engine::output(output_data &output, uint32_t chanmask) +{ + // mask out some channels for debug purposes + chanmask &= debug::GLOBAL_PCM_CHANNEL_MASK; + + // compute the output of each channel + for (int chnum = 0; chnum < CHANNELS; chnum++) + if (bitfield(chanmask, chnum)) + m_channel[chnum]->output(output); +} + + +//------------------------------------------------- +// read - handle reads from the PCM registers +//------------------------------------------------- + +uint8_t pcm_engine::read(uint32_t regnum) +{ + // handle reads from the data register + if (regnum == 0x06 && m_regs.memory_access_mode() != 0) + return m_intf.ymfm_external_read(ACCESS_PCM, m_regs.memory_address_autoinc()); + + return m_regs.read(regnum); +} + + +//------------------------------------------------- +// write - handle writes to the PCM registers +//------------------------------------------------- + +void pcm_engine::write(uint32_t regnum, uint8_t data) +{ + // handle reads to the data register + if (regnum == 0x06 && m_regs.memory_access_mode() != 0) + { + m_intf.ymfm_external_write(ACCESS_PCM, m_regs.memory_address_autoinc(), data); + return; + } + + // for now just mark all channels as modified + m_modified_channels = ALL_CHANNELS; + + // most writes are passive, consumed only when needed + m_regs.write(regnum, data); + + // however, process keyons immediately + if (regnum >= 0x68 && regnum <= 0x7f) + m_channel[regnum - 0x68]->keyonoff(bitfield(data, 7)); + + // and also wavetable writes + else if (regnum >= 0x08 && regnum <= 0x1f) + m_channel[regnum - 0x08]->load_wavetable(); +} + +} |