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Diffstat (limited to '3rdparty/ymfm/src/ymfm_opm.cpp')
-rw-r--r-- | 3rdparty/ymfm/src/ymfm_opm.cpp | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/3rdparty/ymfm/src/ymfm_opm.cpp b/3rdparty/ymfm/src/ymfm_opm.cpp new file mode 100644 index 00000000000..03f54fb9039 --- /dev/null +++ b/3rdparty/ymfm/src/ymfm_opm.cpp @@ -0,0 +1,539 @@ +// 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_opm.h" +#include "ymfm_fm.ipp" + +namespace ymfm +{ + +//********************************************************* +// OPM REGISTERS +//********************************************************* + +//------------------------------------------------- +// opm_registers - constructor +//------------------------------------------------- + +opm_registers::opm_registers() : + m_lfo_counter(0), + m_noise_lfsr(1), + m_noise_counter(0), + m_noise_state(0), + m_noise_lfo(0), + m_lfo_am(0) +{ + // create the waveforms + for (uint32_t index = 0; index < WAVEFORM_LENGTH; index++) + m_waveform[0][index] = abs_sin_attenuation(index) | (bitfield(index, 9) << 15); + + // create the LFO waveforms; AM in the low 8 bits, PM in the upper 8 + // waveforms are adjusted to match the pictures in the application manual + for (uint32_t index = 0; index < LFO_WAVEFORM_LENGTH; index++) + { + // waveform 0 is a sawtooth + uint8_t am = index ^ 0xff; + uint8_t pm = index; + m_lfo_waveform[0][index] = am | (pm << 8); + + // waveform 1 is a square wave + am = bitfield(index, 7) ? 0 : 0xff; + pm = am ^ 0x80; + m_lfo_waveform[1][index] = am | (pm << 8); + + // waveform 2 is a triangle wave + am = bitfield(index, 7) ? (index << 1) : ((index ^ 0xff) << 1); + pm = bitfield(index, 6) ? am : ~am; + m_lfo_waveform[2][index] = am | (pm << 8); + + // waveform 3 is noise; it is filled in dynamically + m_lfo_waveform[3][index] = 0; + } +} + + +//------------------------------------------------- +// reset - reset to initial state +//------------------------------------------------- + +void opm_registers::reset() +{ + std::fill_n(&m_regdata[0], REGISTERS, 0); + + // enable output on both channels by default + m_regdata[0x20] = m_regdata[0x21] = m_regdata[0x22] = m_regdata[0x23] = 0xc0; + m_regdata[0x24] = m_regdata[0x25] = m_regdata[0x26] = m_regdata[0x27] = 0xc0; +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void opm_registers::save_restore(ymfm_saved_state &state) +{ + state.save_restore(m_lfo_counter); + state.save_restore(m_lfo_am); + state.save_restore(m_noise_lfsr); + state.save_restore(m_noise_counter); + state.save_restore(m_noise_state); + state.save_restore(m_noise_lfo); + state.save_restore(m_regdata); +} + + +//------------------------------------------------- +// operator_map - return an array of operator +// indices for each channel; for OPM this is fixed +//------------------------------------------------- + +void opm_registers::operator_map(operator_mapping &dest) const +{ + // Note that the channel index order is 0,2,1,3, so we bitswap the index. + // + // This is because the order in the map is: + // carrier 1, carrier 2, modulator 1, modulator 2 + // + // But when wiring up the connections, the more natural order is: + // carrier 1, modulator 1, carrier 2, modulator 2 + static const operator_mapping s_fixed_map = + { { + operator_list( 0, 16, 8, 24 ), // Channel 0 operators + operator_list( 1, 17, 9, 25 ), // Channel 1 operators + operator_list( 2, 18, 10, 26 ), // Channel 2 operators + operator_list( 3, 19, 11, 27 ), // Channel 3 operators + operator_list( 4, 20, 12, 28 ), // Channel 4 operators + operator_list( 5, 21, 13, 29 ), // Channel 5 operators + operator_list( 6, 22, 14, 30 ), // Channel 6 operators + operator_list( 7, 23, 15, 31 ), // Channel 7 operators + } }; + dest = s_fixed_map; +} + + +//------------------------------------------------- +// write - handle writes to the register array +//------------------------------------------------- + +bool opm_registers::write(uint16_t index, uint8_t data, uint32_t &channel, uint32_t &opmask) +{ + assert(index < REGISTERS); + + // LFO AM/PM depth are written to the same register (0x19); + // redirect the PM depth to an unused neighbor (0x1a) + if (index == 0x19) + m_regdata[index + bitfield(data, 7)] = data; + else if (index != 0x1a) + m_regdata[index] = data; + + // handle writes to the key on index + if (index == 0x08) + { + channel = bitfield(data, 0, 3); + opmask = bitfield(data, 3, 4); + return true; + } + return false; +} + + +//------------------------------------------------- +// clock_noise_and_lfo - clock the noise and LFO, +// handling clock division, depth, and waveform +// computations +//------------------------------------------------- + +int32_t opm_registers::clock_noise_and_lfo() +{ + // base noise frequency is measured at 2x 1/2 FM frequency; this + // means each tick counts as two steps against the noise counter + uint32_t freq = noise_frequency(); + for (int rep = 0; rep < 2; rep++) + { + // evidence seems to suggest the LFSR is clocked continually and just + // sampled at the noise frequency for output purposes; note that the + // low 8 bits are the most recent 8 bits of history while bits 8-24 + // contain the 17 bit LFSR state + m_noise_lfsr <<= 1; + m_noise_lfsr |= bitfield(m_noise_lfsr, 17) ^ bitfield(m_noise_lfsr, 14) ^ 1; + + // compare against the frequency and latch when we exceed it + if (m_noise_counter++ >= freq) + { + m_noise_counter = 0; + m_noise_state = bitfield(m_noise_lfsr, 17); + } + } + + // treat the rate as a 4.4 floating-point step value with implied + // leading 1; this matches exactly the frequencies in the application + // manual, though it might not be implemented exactly this way on chip + uint32_t rate = lfo_rate(); + m_lfo_counter += (0x10 | bitfield(rate, 0, 4)) << bitfield(rate, 4, 4); + + // bit 1 of the test register is officially undocumented but has been + // discovered to hold the LFO in reset while active + if (lfo_reset()) + m_lfo_counter = 0; + + // now pull out the non-fractional LFO value + uint32_t lfo = bitfield(m_lfo_counter, 22, 8); + + // fill in the noise entry 1 ahead of our current position; this + // ensures the current value remains stable for a full LFO clock + // and effectively latches the running value when the LFO advances + uint32_t lfo_noise = bitfield(m_noise_lfsr, 17, 8); + m_lfo_waveform[3][(lfo + 1) & 0xff] = lfo_noise | (lfo_noise << 8); + + // fetch the AM/PM values based on the waveform; AM is unsigned and + // encoded in the low 8 bits, while PM signed and encoded in the upper + // 8 bits + int32_t ampm = m_lfo_waveform[lfo_waveform()][lfo]; + + // apply depth to the AM value and store for later + m_lfo_am = ((ampm & 0xff) * lfo_am_depth()) >> 7; + + // apply depth to the PM value and return it + return ((ampm >> 8) * int32_t(lfo_pm_depth())) >> 7; +} + + +//------------------------------------------------- +// lfo_am_offset - return the AM offset from LFO +// for the given channel +//------------------------------------------------- + +uint32_t opm_registers::lfo_am_offset(uint32_t choffs) const +{ + // OPM maps AM quite differently from OPN + + // shift value for AM sensitivity is [*, 0, 1, 2], + // mapping to values of [0, 23.9, 47.8, and 95.6dB] + uint32_t am_sensitivity = ch_lfo_am_sens(choffs); + if (am_sensitivity == 0) + return 0; + + // QUESTION: see OPN note below for the dB range mapping; it applies + // here as well + + // raw LFO AM value on OPM is 0-FF, which is already a factor of 2 + // larger than the OPN below, putting our staring point at 2x theirs; + // this works out since our minimum is 2x their maximum + return m_lfo_am << (am_sensitivity - 1); +} + + +//------------------------------------------------- +// cache_operator_data - fill the operator cache +// with prefetched data +//------------------------------------------------- + +void opm_registers::cache_operator_data(uint32_t choffs, uint32_t opoffs, opdata_cache &cache) +{ + // set up the easy stuff + cache.waveform = &m_waveform[0][0]; + + // get frequency from the channel + uint32_t block_freq = cache.block_freq = ch_block_freq(choffs); + + // compute the keycode: block_freq is: + // + // BBBCCCCFFFFFF + // ^^^^^ + // + // the 5-bit keycode is just the top 5 bits (block + top 2 bits + // of the key code) + uint32_t keycode = bitfield(block_freq, 8, 5); + + // detune adjustment + cache.detune = detune_adjustment(op_detune(opoffs), keycode); + + // multiple value, as an x.1 value (0 means 0.5) + cache.multiple = op_multiple(opoffs) * 2; + if (cache.multiple == 0) + cache.multiple = 1; + + // phase step, or PHASE_STEP_DYNAMIC if PM is active; this depends on + // block_freq, detune, and multiple, so compute it after we've done those + if (lfo_pm_depth() == 0 || ch_lfo_pm_sens(choffs) == 0) + cache.phase_step = compute_phase_step(choffs, opoffs, cache, 0); + else + cache.phase_step = opdata_cache::PHASE_STEP_DYNAMIC; + + // total level, scaled by 8 + cache.total_level = op_total_level(opoffs) << 3; + + // 4-bit sustain level, but 15 means 31 so effectively 5 bits + cache.eg_sustain = op_sustain_level(opoffs); + cache.eg_sustain |= (cache.eg_sustain + 1) & 0x10; + cache.eg_sustain <<= 5; + + // determine KSR adjustment for enevlope rates + uint32_t ksrval = keycode >> (op_ksr(opoffs) ^ 3); + cache.eg_rate[EG_ATTACK] = effective_rate(op_attack_rate(opoffs) * 2, ksrval); + cache.eg_rate[EG_DECAY] = effective_rate(op_decay_rate(opoffs) * 2, ksrval); + cache.eg_rate[EG_SUSTAIN] = effective_rate(op_sustain_rate(opoffs) * 2, ksrval); + cache.eg_rate[EG_RELEASE] = effective_rate(op_release_rate(opoffs) * 4 + 2, ksrval); +} + + +//------------------------------------------------- +// compute_phase_step - compute the phase step +//------------------------------------------------- + +uint32_t opm_registers::compute_phase_step(uint32_t choffs, uint32_t opoffs, opdata_cache const &cache, int32_t lfo_raw_pm) +{ + // OPM logic is rather unique here, due to extra detune + // and the use of key codes (not to be confused with keycode) + + // start with coarse detune delta; table uses cents value from + // manual, converted into 1/64ths + static const int16_t s_detune2_delta[4] = { 0, (600*64+50)/100, (781*64+50)/100, (950*64+50)/100 }; + int32_t delta = s_detune2_delta[op_detune2(opoffs)]; + + // add in the PM delta + uint32_t pm_sensitivity = ch_lfo_pm_sens(choffs); + if (pm_sensitivity != 0) + { + // raw PM value is -127..128 which is +/- 200 cents + // manual gives these magnitudes in cents: + // 0, +/-5, +/-10, +/-20, +/-50, +/-100, +/-400, +/-700 + // this roughly corresponds to shifting the 200-cent value: + // 0 >> 5, >> 4, >> 3, >> 2, >> 1, << 1, << 2 + if (pm_sensitivity < 6) + delta += lfo_raw_pm >> (6 - pm_sensitivity); + else + delta += uint32_t(lfo_raw_pm) << (pm_sensitivity - 5); + } + + // apply delta and convert to a frequency number + uint32_t phase_step = opm_key_code_to_phase_step(cache.block_freq, delta); + + // apply detune based on the keycode + phase_step += cache.detune; + + // apply frequency multiplier (which is cached as an x.1 value) + return (phase_step * cache.multiple) >> 1; +} + + +//------------------------------------------------- +// log_keyon - log a key-on event +//------------------------------------------------- + +std::string opm_registers::log_keyon(uint32_t choffs, uint32_t opoffs) +{ + uint32_t chnum = choffs; + uint32_t opnum = opoffs; + + char buffer[256]; + int end = 0; + + end += snprintf(&buffer[end], sizeof(buffer) - end, "%u.%02u freq=%04X dt2=%u dt=%u fb=%u alg=%X mul=%X tl=%02X ksr=%u adsr=%02X/%02X/%02X/%X sl=%X out=%c%c", + chnum, opnum, + ch_block_freq(choffs), + op_detune2(opoffs), + op_detune(opoffs), + ch_feedback(choffs), + ch_algorithm(choffs), + op_multiple(opoffs), + op_total_level(opoffs), + op_ksr(opoffs), + op_attack_rate(opoffs), + op_decay_rate(opoffs), + op_sustain_rate(opoffs), + op_release_rate(opoffs), + op_sustain_level(opoffs), + ch_output_0(choffs) ? 'L' : '-', + ch_output_1(choffs) ? 'R' : '-'); + + bool am = (lfo_am_depth() != 0 && ch_lfo_am_sens(choffs) != 0 && op_lfo_am_enable(opoffs) != 0); + if (am) + end += snprintf(&buffer[end], sizeof(buffer) - end, " am=%u/%02X", ch_lfo_am_sens(choffs), lfo_am_depth()); + bool pm = (lfo_pm_depth() != 0 && ch_lfo_pm_sens(choffs) != 0); + if (pm) + end += snprintf(&buffer[end], sizeof(buffer) - end, " pm=%u/%02X", ch_lfo_pm_sens(choffs), lfo_pm_depth()); + if (am || pm) + end += snprintf(&buffer[end], sizeof(buffer) - end, " lfo=%02X/%c", lfo_rate(), "WQTN"[lfo_waveform()]); + if (noise_enable() && opoffs == 31) + end += snprintf(&buffer[end], sizeof(buffer) - end, " noise=1"); + + return buffer; +} + + + +//********************************************************* +// YM2151 +//********************************************************* + +//------------------------------------------------- +// ym2151 - constructor +//------------------------------------------------- + +ym2151::ym2151(ymfm_interface &intf, opm_variant variant) : + m_variant(variant), + m_address(0), + m_fm(intf) +{ +} + + +//------------------------------------------------- +// reset - reset the system +//------------------------------------------------- + +void ym2151::reset() +{ + // reset the engines + m_fm.reset(); +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void ym2151::save_restore(ymfm_saved_state &state) +{ + m_fm.save_restore(state); + state.save_restore(m_address); +} + + +//------------------------------------------------- +// read_status - read the status register +//------------------------------------------------- + +uint8_t ym2151::read_status() +{ + uint8_t result = m_fm.status(); + if (m_fm.intf().ymfm_is_busy()) + result |= fm_engine::STATUS_BUSY; + return result; +} + + +//------------------------------------------------- +// read - handle a read from the device +//------------------------------------------------- + +uint8_t ym2151::read(uint32_t offset) +{ + uint8_t result = 0xff; + switch (offset & 1) + { + case 0: // data port (unused) + debug::log_unexpected_read_write("Unexpected read from YM2151 offset %d\n", offset & 3); + break; + + case 1: // status port, YM2203 compatible + result = read_status(); + break; + } + return result; +} + + +//------------------------------------------------- +// write_address - handle a write to the address +// register +//------------------------------------------------- + +void ym2151::write_address(uint8_t data) +{ + // just set the address + m_address = data; +} + + +//------------------------------------------------- +// write - handle a write to the register +// interface +//------------------------------------------------- + +void ym2151::write_data(uint8_t data) +{ + // write the FM register + m_fm.write(m_address, data); + + // special cases + if (m_address == 0x1b) + { + // writes to register 0x1B send the upper 2 bits to the output lines + m_fm.intf().ymfm_external_write(ACCESS_IO, 0, data >> 6); + } + + // mark busy for a bit + m_fm.intf().ymfm_set_busy_end(32 * m_fm.clock_prescale()); +} + + +//------------------------------------------------- +// write - handle a write to the register +// interface +//------------------------------------------------- + +void ym2151::write(uint32_t offset, uint8_t data) +{ + switch (offset & 1) + { + case 0: // address port + write_address(data); + break; + + case 1: // data port + write_data(data); + break; + } +} + + +//------------------------------------------------- +// generate - generate one sample of sound +//------------------------------------------------- + +void ym2151::generate(output_data *output, uint32_t numsamples) +{ + for (uint32_t samp = 0; samp < numsamples; samp++, output++) + { + // clock the system + m_fm.clock(fm_engine::ALL_CHANNELS); + + // update the FM content; OPM is full 14-bit with no intermediate clipping + m_fm.output(output->clear(), 0, 32767, fm_engine::ALL_CHANNELS); + + // YM2151 uses an external DAC (YM3012) with mantissa/exponent format + // convert to 10.3 floating point value and back to simulate truncation + output->roundtrip_fp(); + } +} + +} |