Files
86Box/src/sound/ymfm/ymfm_opq.cpp
2024-12-06 21:37:02 -05:00

481 lines
15 KiB
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// 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_opq.h"
#include "ymfm_fm.ipp"
#define TEMPORARY_DEBUG_PRINTS (0)
//
// OPQ (aka YM3806/YM3533)
//
// This chip is not officially documented as far as I know. What I have
// comes from Jari Kangas' work on reverse engineering the PSR70:
//
// https://github.com/JKN0/PSR70-reverse
//
// OPQ appears be bsaically a mixture of OPM and OPN.
//
namespace ymfm
{
//*********************************************************
// OPQ SPECIFICS
//*********************************************************
//-------------------------------------------------
// opq_registers - constructor
//-------------------------------------------------
opq_registers::opq_registers() :
m_lfo_counter(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);
uint16_t zeroval = m_waveform[0][0];
for (uint32_t index = 0; index < WAVEFORM_LENGTH; index++)
m_waveform[1][index] = bitfield(index, 9) ? zeroval : m_waveform[0][index];
}
//-------------------------------------------------
// reset - reset to initial state
//-------------------------------------------------
void opq_registers::reset()
{
std::fill_n(&m_regdata[0], REGISTERS, 0);
// enable output on both channels by default
m_regdata[0x10] = m_regdata[0x11] = m_regdata[0x12] = m_regdata[0x13] = 0xc0;
m_regdata[0x14] = m_regdata[0x15] = m_regdata[0x16] = m_regdata[0x17] = 0xc0;
}
//-------------------------------------------------
// save_restore - save or restore the data
//-------------------------------------------------
void opq_registers::save_restore(ymfm_saved_state &state)
{
state.save_restore(m_lfo_counter);
state.save_restore(m_lfo_am);
state.save_restore(m_regdata);
}
//-------------------------------------------------
// operator_map - return an array of operator
// indices for each channel; for OPM this is fixed
//-------------------------------------------------
void opq_registers::operator_map(operator_mapping &dest) const
{
// seems like the operators are not swizzled like they are on OPM/OPN?
static const operator_mapping s_fixed_map =
{ {
operator_list( 0, 8, 16, 24 ), // Channel 0 operators
operator_list( 1, 9, 17, 25 ), // Channel 1 operators
operator_list( 2, 10, 18, 26 ), // Channel 2 operators
operator_list( 3, 11, 19, 27 ), // Channel 3 operators
operator_list( 4, 12, 20, 28 ), // Channel 4 operators
operator_list( 5, 13, 21, 29 ), // Channel 5 operators
operator_list( 6, 14, 22, 30 ), // Channel 6 operators
operator_list( 7, 15, 23, 31 ), // Channel 7 operators
} };
dest = s_fixed_map;
}
//-------------------------------------------------
// write - handle writes to the register array
//-------------------------------------------------
bool opq_registers::write(uint16_t index, uint8_t data, uint32_t &channel, uint32_t &opmask)
{
assert(index < REGISTERS);
// detune/multiple share a register based on the MSB of what is written
// remap the multiple values to 100-11F
if ((index & 0xe0) == 0x40 && bitfield(data, 7) != 0)
index += 0xc0;
m_regdata[index] = data;
// handle writes to the key on index
if (index == 0x05)
{
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 opq_registers::clock_noise_and_lfo()
{
// OPQ LFO is not well-understood, but the enable and rate values
// look a lot like OPN, so we'll crib from there as a starting point
// if LFO not enabled (not present on OPN), quick exit with 0s
if (!lfo_enable())
{
m_lfo_counter = 0;
m_lfo_am = 0;
return 0;
}
// this table is based on converting the frequencies in the applications
// manual to clock dividers, based on the assumption of a 7-bit LFO value
static uint8_t const lfo_max_count[8] = { 109, 78, 72, 68, 63, 45, 9, 6 };
uint32_t subcount = uint8_t(m_lfo_counter++);
// when we cross the divider count, add enough to zero it and cause an
// increment at bit 8; the 7-bit value lives from bits 8-14
if (subcount >= lfo_max_count[lfo_rate()])
m_lfo_counter += 0x101 - subcount;
// AM value is 7 bits, staring at bit 8; grab the low 6 directly
m_lfo_am = bitfield(m_lfo_counter, 8, 6);
// first half of the AM period (bit 6 == 0) is inverted
if (bitfield(m_lfo_counter, 8+6) == 0)
m_lfo_am ^= 0x3f;
// PM value is 5 bits, starting at bit 10; grab the low 3 directly
int32_t pm = bitfield(m_lfo_counter, 10, 3);
// PM is reflected based on bit 3
if (bitfield(m_lfo_counter, 10+3))
pm ^= 7;
// PM is negated based on bit 4
return bitfield(m_lfo_counter, 10+4) ? -pm : pm;
}
//-------------------------------------------------
// lfo_am_offset - return the AM offset from LFO
// for the given channel
//-------------------------------------------------
uint32_t opq_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 opq_registers::cache_operator_data(uint32_t choffs, uint32_t opoffs, opdata_cache &cache)
{
// set up the easy stuff
cache.waveform = &m_waveform[op_waveform(opoffs)][0];
// get frequency from the appropriate registers
uint32_t block_freq = cache.block_freq = (opoffs & 8) ? ch_block_freq_24(choffs) : ch_block_freq_13(choffs);
// compute the keycode: block_freq is:
//
// BBBFFFFFFFFFFFF
// ^^^^???
//
// keycode is not understood, so just guessing it is like OPN:
// the 5-bit keycode uses the top 4 bits plus a magic formula
// for the final bit
uint32_t keycode = bitfield(block_freq, 11, 4) << 1;
// lowest bit is determined by a mix of next lower FNUM bits
// according to this equation from the YM2608 manual:
//
// (F11 & (F10 | F9 | F8)) | (!F11 & F10 & F9 & F8)
//
// for speed, we just look it up in a 16-bit constant
keycode |= bitfield(0xfe80, bitfield(block_freq, 8, 4));
// detune adjustment: the detune values supported by the OPQ are
// a much larger range (6 bits vs 3 bits) compared to any other
// known FM chip; based on experiments, it seems that the extra
// bits provide a bigger detune range rather than finer control,
// so until we get true measurements just assemble a net detune
// value by summing smaller detunes
int32_t detune = int32_t(op_detune(opoffs)) - 0x20;
int32_t abs_detune = std::abs(detune);
int32_t adjust = (abs_detune / 3) * detune_adjustment(3, keycode) + detune_adjustment(abs_detune % 3, keycode);
cache.detune = (detune >= 0) ? adjust : -adjust;
// multiple value, as an x.1 value (0 means 0.5)
static const uint8_t s_multiple_map[16] = { 1,2,4,6,8,10,12,14,16,18,20,24,30,32,34,36 };
cache.multiple = s_multiple_map[op_multiple(opoffs)];
// 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_enable() == 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);
cache.eg_rate[EG_REVERB] = (ch_reverb(choffs) != 0) ? 5*4 : cache.eg_rate[EG_RELEASE];
cache.eg_shift = 0;
}
//-------------------------------------------------
// compute_phase_step - compute the phase step
//-------------------------------------------------
uint32_t opq_registers::compute_phase_step(uint32_t choffs, uint32_t opoffs, opdata_cache const &cache, int32_t lfo_raw_pm)
{
// OPN phase calculation has only a single detune parameter
// and uses FNUMs instead of keycodes
// extract frequency number (low 12 bits of block_freq)
uint32_t fnum = bitfield(cache.block_freq, 0, 12);
// if there's a non-zero PM sensitivity, compute the adjustment
uint32_t pm_sensitivity = ch_lfo_pm_sens(choffs);
if (pm_sensitivity != 0)
{
// apply the phase adjustment based on the upper 7 bits
// of FNUM and the PM depth parameters
fnum += opn_lfo_pm_phase_adjustment(bitfield(cache.block_freq, 5, 7), pm_sensitivity, lfo_raw_pm);
// keep fnum to 12 bits
fnum &= 0xfff;
}
// apply block shift to compute phase step
uint32_t block = bitfield(cache.block_freq, 12, 3);
uint32_t phase_step = (fnum << block) >> 2;
// apply detune based on the keycode
phase_step += cache.detune;
// clamp to 17 bits in case detune overflows
// QUESTION: is this specific to the YM2612/3438?
phase_step &= 0x1ffff;
// 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 opq_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 dt=%+2d fb=%u alg=%X mul=%X tl=%02X ksr=%u adsr=%02X/%02X/%02X/%X sl=%X out=%c%c",
chnum, opnum,
(opoffs & 1) ? ch_block_freq_24(choffs) : ch_block_freq_13(choffs),
int32_t(op_detune(opoffs)) - 0x20,
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_enable() && op_lfo_am_enable(opoffs) && ch_lfo_am_sens(choffs) != 0);
if (am)
end += snprintf(&buffer[end], sizeof(buffer) - end, " am=%u", ch_lfo_am_sens(choffs));
bool pm = (lfo_enable() && ch_lfo_pm_sens(choffs) != 0);
if (pm)
end += snprintf(&buffer[end], sizeof(buffer) - end, " pm=%u", ch_lfo_pm_sens(choffs));
if (am || pm)
end += snprintf(&buffer[end], sizeof(buffer) - end, " lfo=%02X", lfo_rate());
if (ch_reverb(choffs))
end += snprintf(&buffer[end], sizeof(buffer) - end, " reverb");
return buffer;
}
//*********************************************************
// YM3806
//*********************************************************
//-------------------------------------------------
// ym3806 - constructor
//-------------------------------------------------
ym3806::ym3806(ymfm_interface &intf) :
m_fm(intf)
{
}
//-------------------------------------------------
// reset - reset the system
//-------------------------------------------------
void ym3806::reset()
{
// reset the engines
m_fm.reset();
}
//-------------------------------------------------
// save_restore - save or restore the data
//-------------------------------------------------
void ym3806::save_restore(ymfm_saved_state &state)
{
m_fm.save_restore(state);
}
//-------------------------------------------------
// read_status - read the status register
//-------------------------------------------------
uint8_t ym3806::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 ym3806::read(uint32_t offset)
{
uint8_t result = 0xff;
switch (offset)
{
case 0: // status port
result = read_status();
break;
default: // unknown
debug::log_unexpected_read_write("Unexpected read from YM3806 offset %02X\n", offset);
break;
}
if (TEMPORARY_DEBUG_PRINTS && offset != 0) printf("Read %02X = %02X\n", offset, result);
return result;
}
//-------------------------------------------------
// write - handle a write to the register
// interface
//-------------------------------------------------
void ym3806::write(uint32_t offset, uint8_t data)
{
if (TEMPORARY_DEBUG_PRINTS && (offset != 3 || data != 0x71)) printf("Write %02X = %02X\n", offset, data);
// write the FM register
m_fm.write(offset, data);
}
//-------------------------------------------------
// generate - generate one sample of sound
//-------------------------------------------------
void ym3806::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; YM3806 is full 14-bit with no intermediate clipping
m_fm.output(output->clear(), 0, 32767, fm_engine::ALL_CHANNELS);
// YM3608 appears to go through a YM3012 DAC, which means we want to apply
// the FP truncation logic to the outputs
output->roundtrip_fp();
}
}
}