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Diffstat (limited to '3rdparty/ymfm/src/ymfm_fm.h')
-rw-r--r-- | 3rdparty/ymfm/src/ymfm_fm.h | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/3rdparty/ymfm/src/ymfm_fm.h b/3rdparty/ymfm/src/ymfm_fm.h new file mode 100644 index 00000000000..81795f8fe43 --- /dev/null +++ b/3rdparty/ymfm/src/ymfm_fm.h @@ -0,0 +1,463 @@ +// 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. + +#ifndef YMFM_FM_H +#define YMFM_FM_H + +#pragma once + +#define YMFM_DEBUG_LOG_WAVFILES (0) + +namespace ymfm +{ + +//********************************************************* +// GLOBAL ENUMERATORS +//********************************************************* + +// three different keyon sources; actual keyon is an OR over all of these +enum keyon_type : uint32_t +{ + KEYON_NORMAL = 0, + KEYON_RHYTHM = 1, + KEYON_CSM = 2 +}; + + + +//********************************************************* +// CORE IMPLEMENTATION +//********************************************************* + +// ======================> opdata_cache + +// this class holds data that is computed once at the start of clocking +// and remains static during subsequent sound generation +struct opdata_cache +{ + // set phase_step to this value to recalculate it each sample; needed + // in the case of PM LFO changes + static constexpr uint32_t PHASE_STEP_DYNAMIC = 1; + + uint16_t const *waveform; // base of sine table + uint32_t phase_step; // phase step, or PHASE_STEP_DYNAMIC if PM is active + uint32_t total_level; // total level * 8 + KSL + uint32_t block_freq; // raw block frequency value (used to compute phase_step) + int32_t detune; // detuning value (used to compute phase_step) + uint32_t multiple; // multiple value (x.1, used to compute phase_step) + uint32_t eg_sustain; // sustain level, shifted up to envelope values + uint8_t eg_rate[EG_STATES]; // envelope rate, including KSR + uint8_t eg_shift = 0; // envelope shift amount +}; + + +// ======================> fm_registers_base + +// base class for family-specific register classes; this provides a few +// constants, common defaults, and helpers, but mostly each derived class is +// responsible for defining all commonly-called methods +class fm_registers_base +{ +public: + // this value is returned from the write() function for rhythm channels + static constexpr uint32_t RHYTHM_CHANNEL = 0xff; + + // this is the size of a full sin waveform + static constexpr uint32_t WAVEFORM_LENGTH = 0x400; + + // + // the following constants need to be defined per family: + // uint32_t OUTPUTS: The number of outputs exposed (1-4) + // uint32_t CHANNELS: The number of channels on the chip + // uint32_t ALL_CHANNELS: A bitmask of all channels + // uint32_t OPERATORS: The number of operators on the chip + // uint32_t WAVEFORMS: The number of waveforms offered + // uint32_t REGISTERS: The number of 8-bit registers allocated + // uint32_t DEFAULT_PRESCALE: The starting clock prescale + // uint32_t EG_CLOCK_DIVIDER: The clock divider of the envelope generator + // uint32_t CSM_TRIGGER_MASK: Mask of channels to trigger in CSM mode + // uint32_t REG_MODE: The address of the "mode" register controlling timers + // uint8_t STATUS_TIMERA: Status bit to set when timer A fires + // uint8_t STATUS_TIMERB: Status bit to set when tiemr B fires + // uint8_t STATUS_BUSY: Status bit to set when the chip is busy + // uint8_t STATUS_IRQ: Status bit to set when an IRQ is signalled + // + // the following constants are uncommon: + // bool DYNAMIC_OPS: True if ops/channel can be changed at runtime (OPL3+) + // bool EG_HAS_DEPRESS: True if the chip has a DP ("depress"?) envelope stage (OPLL) + // bool EG_HAS_REVERB: True if the chip has a faux reverb envelope stage (OPQ/OPZ) + // bool EG_HAS_SSG: True if the chip has SSG envelope support (OPN) + // bool MODULATOR_DELAY: True if the modulator is delayed by 1 sample (OPL pre-OPL3) + // + static constexpr bool DYNAMIC_OPS = false; + static constexpr bool EG_HAS_DEPRESS = false; + static constexpr bool EG_HAS_REVERB = false; + static constexpr bool EG_HAS_SSG = false; + static constexpr bool MODULATOR_DELAY = false; + + // system-wide register defaults + uint32_t status_mask() const { return 0; } // OPL only + uint32_t irq_reset() const { return 0; } // OPL only + uint32_t noise_enable() const { return 0; } // OPM only + uint32_t rhythm_enable() const { return 0; } // OPL only + + // per-operator register defaults + uint32_t op_ssg_eg_enable(uint32_t opoffs) const { return 0; } // OPN(A) only + uint32_t op_ssg_eg_mode(uint32_t opoffs) const { return 0; } // OPN(A) only + +protected: + // helper to encode four operator numbers into a 32-bit value in the + // operator maps for each register class + static constexpr uint32_t operator_list(uint8_t o1 = 0xff, uint8_t o2 = 0xff, uint8_t o3 = 0xff, uint8_t o4 = 0xff) + { + return o1 | (o2 << 8) | (o3 << 16) | (o4 << 24); + } + + // helper to apply KSR to the raw ADSR rate, ignoring ksr if the + // raw value is 0, and clamping to 63 + static constexpr uint32_t effective_rate(uint32_t rawrate, uint32_t ksr) + { + return (rawrate == 0) ? 0 : std::min<uint32_t>(rawrate + ksr, 63); + } +}; + + + +//********************************************************* +// CORE ENGINE CLASSES +//********************************************************* + +// forward declarations +template<class RegisterType> class fm_engine_base; + +// ======================> fm_operator + +// fm_operator represents an FM operator (or "slot" in FM parlance), which +// produces an output sine wave modulated by an envelope +template<class RegisterType> +class fm_operator +{ + // "quiet" value, used to optimize when we can skip doing work + static constexpr uint32_t EG_QUIET = 0x380; + +public: + // constructor + fm_operator(fm_engine_base<RegisterType> &owner, uint32_t opoffs); + + // save/restore + void save_restore(ymfm_saved_state &state); + + // reset the operator state + void reset(); + + // return the operator/channel offset + uint32_t opoffs() const { return m_opoffs; } + uint32_t choffs() const { return m_choffs; } + + // set the current channel + void set_choffs(uint32_t choffs) { m_choffs = choffs; } + + // prepare prior to clocking + bool prepare(); + + // master clocking function + void clock(uint32_t env_counter, int32_t lfo_raw_pm); + + // return the current phase value + uint32_t phase() const { return m_phase >> 10; } + + // compute operator volume + int32_t compute_volume(uint32_t phase, uint32_t am_offset) const; + + // compute volume for the OPM noise channel + int32_t compute_noise_volume(uint32_t am_offset) const; + + // key state control + void keyonoff(uint32_t on, keyon_type type); + + // return a reference to our registers + RegisterType ®s() const { return m_regs; } + + // simple getters for debugging + envelope_state debug_eg_state() const { return m_env_state; } + uint16_t debug_eg_attenuation() const { return m_env_attenuation; } + uint8_t debug_ssg_inverted() const { return m_ssg_inverted; } + opdata_cache &debug_cache() { return m_cache; } + +private: + // start the attack phase + void start_attack(bool is_restart = false); + + // start the release phase + void start_release(); + + // clock phases + void clock_keystate(uint32_t keystate); + void clock_ssg_eg_state(); + void clock_envelope(uint32_t env_counter); + void clock_phase(int32_t lfo_raw_pm); + + // return effective attenuation of the envelope + uint32_t envelope_attenuation(uint32_t am_offset) const; + + // internal state + uint32_t m_choffs; // channel offset in registers + uint32_t m_opoffs; // operator offset in registers + uint32_t m_phase; // current phase value (10.10 format) + uint16_t m_env_attenuation; // computed envelope attenuation (4.6 format) + envelope_state m_env_state; // current envelope state + uint8_t m_ssg_inverted; // non-zero if the output should be inverted (bit 0) + uint8_t m_key_state; // current key state: on or off (bit 0) + uint8_t m_keyon_live; // live key on state (bit 0 = direct, bit 1 = rhythm, bit 2 = CSM) + opdata_cache m_cache; // cached values for performance + RegisterType &m_regs; // direct reference to registers + fm_engine_base<RegisterType> &m_owner; // reference to the owning engine +}; + + +// ======================> fm_channel + +// fm_channel represents an FM channel which combines the output of 2 or 4 +// operators into a final result +template<class RegisterType> +class fm_channel +{ + using output_data = ymfm_output<RegisterType::OUTPUTS>; + +public: + // constructor + fm_channel(fm_engine_base<RegisterType> &owner, uint32_t choffs); + + // save/restore + void save_restore(ymfm_saved_state &state); + + // reset the channel state + void reset(); + + // return the channel offset + uint32_t choffs() const { return m_choffs; } + + // assign operators + void assign(uint32_t index, fm_operator<RegisterType> *op) + { + assert(index < array_size(m_op)); + m_op[index] = op; + if (op != nullptr) + op->set_choffs(m_choffs); + } + + // signal key on/off to our operators + void keyonoff(uint32_t states, keyon_type type, uint32_t chnum); + + // prepare prior to clocking + bool prepare(); + + // master clocking function + void clock(uint32_t env_counter, int32_t lfo_raw_pm); + + // specific 2-operator and 4-operator output handlers + void output_2op(output_data &output, uint32_t rshift, int32_t clipmax) const; + void output_4op(output_data &output, uint32_t rshift, int32_t clipmax) const; + + // compute the special OPL rhythm channel outputs + void output_rhythm_ch6(output_data &output, uint32_t rshift, int32_t clipmax) const; + void output_rhythm_ch7(uint32_t phase_select, output_data &output, uint32_t rshift, int32_t clipmax) const; + void output_rhythm_ch8(uint32_t phase_select, output_data &output, uint32_t rshift, int32_t clipmax) const; + + // are we a 4-operator channel or a 2-operator one? + bool is4op() const + { + if (RegisterType::DYNAMIC_OPS) + return (m_op[2] != nullptr); + return (RegisterType::OPERATORS / RegisterType::CHANNELS == 4); + } + + // return a reference to our registers + RegisterType ®s() const { return m_regs; } + + // simple getters for debugging + fm_operator<RegisterType> *debug_operator(uint32_t index) const { return m_op[index]; } + +private: + // helper to add values to the outputs based on channel enables + void add_to_output(uint32_t choffs, output_data &output, int32_t value) const + { + // create these constants to appease overzealous compilers checking array + // bounds in unreachable code (looking at you, clang) + constexpr int out0_index = 0; + constexpr int out1_index = 1 % RegisterType::OUTPUTS; + constexpr int out2_index = 2 % RegisterType::OUTPUTS; + constexpr int out3_index = 3 % RegisterType::OUTPUTS; + + if (RegisterType::OUTPUTS == 1 || m_regs.ch_output_0(choffs)) + output.data[out0_index] += value; + if (RegisterType::OUTPUTS >= 2 && m_regs.ch_output_1(choffs)) + output.data[out1_index] += value; + if (RegisterType::OUTPUTS >= 3 && m_regs.ch_output_2(choffs)) + output.data[out2_index] += value; + if (RegisterType::OUTPUTS >= 4 && m_regs.ch_output_3(choffs)) + output.data[out3_index] += value; + } + + // internal state + uint32_t m_choffs; // channel offset in registers + int16_t m_feedback[2]; // feedback memory for operator 1 + mutable int16_t m_feedback_in; // next input value for op 1 feedback (set in output) + fm_operator<RegisterType> *m_op[4]; // up to 4 operators + RegisterType &m_regs; // direct reference to registers + fm_engine_base<RegisterType> &m_owner; // reference to the owning engine +}; + + +// ======================> fm_engine_base + +// fm_engine_base represents a set of operators and channels which together +// form a Yamaha FM core; chips that implement other engines (ADPCM, wavetable, +// etc) take this output and combine it with the others externally +template<class RegisterType> +class fm_engine_base : public ymfm_engine_callbacks +{ +public: + // expose some constants from the registers + static constexpr uint32_t OUTPUTS = RegisterType::OUTPUTS; + static constexpr uint32_t CHANNELS = RegisterType::CHANNELS; + static constexpr uint32_t ALL_CHANNELS = RegisterType::ALL_CHANNELS; + static constexpr uint32_t OPERATORS = RegisterType::OPERATORS; + + // also expose status flags for consumers that inject additional bits + static constexpr uint8_t STATUS_TIMERA = RegisterType::STATUS_TIMERA; + static constexpr uint8_t STATUS_TIMERB = RegisterType::STATUS_TIMERB; + static constexpr uint8_t STATUS_BUSY = RegisterType::STATUS_BUSY; + static constexpr uint8_t STATUS_IRQ = RegisterType::STATUS_IRQ; + + // expose the correct output class + using output_data = ymfm_output<OUTPUTS>; + + // constructor + fm_engine_base(ymfm_interface &intf); + + // save/restore + void save_restore(ymfm_saved_state &state); + + // reset the overall state + void reset(); + + // master clocking function + uint32_t clock(uint32_t chanmask); + + // compute sum of channel outputs + void output(output_data &output, uint32_t rshift, int32_t clipmax, uint32_t chanmask) const; + + // write to the OPN registers + void write(uint16_t regnum, uint8_t data); + + // return the current status + uint8_t status() const; + + // set/reset bits in the status register, updating the IRQ status + uint8_t set_reset_status(uint8_t set, uint8_t reset) + { + m_status = (m_status | set) & ~(reset | STATUS_BUSY); + m_intf.ymfm_sync_check_interrupts(); + return m_status & ~m_regs.status_mask(); + } + + // set the IRQ mask + void set_irq_mask(uint8_t mask) { m_irq_mask = mask; m_intf.ymfm_sync_check_interrupts(); } + + // return the current clock prescale + uint32_t clock_prescale() const { return m_clock_prescale; } + + // set prescale factor (2/3/6) + void set_clock_prescale(uint32_t prescale) { m_clock_prescale = prescale; } + + // compute sample rate + uint32_t sample_rate(uint32_t baseclock) const + { +#if (YMFM_DEBUG_LOG_WAVFILES) + for (uint32_t chnum = 0; chnum < CHANNELS; chnum++) + m_wavfile[chnum].set_samplerate(baseclock / (m_clock_prescale * OPERATORS)); +#endif + return baseclock / (m_clock_prescale * OPERATORS); + } + + // return the owning device + ymfm_interface &intf() const { return m_intf; } + + // return a reference to our registers + RegisterType ®s() { return m_regs; } + + // invalidate any caches + void invalidate_caches() { m_modified_channels = RegisterType::ALL_CHANNELS; } + + // simple getters for debugging + fm_channel<RegisterType> *debug_channel(uint32_t index) const { return m_channel[index].get(); } + fm_operator<RegisterType> *debug_operator(uint32_t index) const { return m_operator[index].get(); } + +public: + // timer callback; called by the interface when a timer fires + virtual void engine_timer_expired(uint32_t tnum) override; + + // check interrupts; called by the interface after synchronization + virtual void engine_check_interrupts() override; + + // mode register write; called by the interface after synchronization + virtual void engine_mode_write(uint8_t data) override; + +protected: + // assign the current set of operators to channels + void assign_operators(); + + // update the state of the given timer + void update_timer(uint32_t which, uint32_t enable, int32_t delta_clocks); + + // internal state + ymfm_interface &m_intf; // reference to the system interface + uint32_t m_env_counter; // envelope counter; low 2 bits are sub-counter + uint8_t m_status; // current status register + uint8_t m_clock_prescale; // prescale factor (2/3/6) + uint8_t m_irq_mask; // mask of which bits signal IRQs + uint8_t m_irq_state; // current IRQ state + uint8_t m_timer_running[2]; // current timer running state + uint8_t m_total_clocks; // low 8 bits of the total number of clocks processed + uint32_t m_active_channels; // mask of active channels (computed by prepare) + uint32_t m_modified_channels; // mask of channels that have been modified + uint32_t m_prepare_count; // counter to do periodic prepare sweeps + RegisterType m_regs; // register accessor + std::unique_ptr<fm_channel<RegisterType>> m_channel[CHANNELS]; // channel pointers + std::unique_ptr<fm_operator<RegisterType>> m_operator[OPERATORS]; // operator pointers +#if (YMFM_DEBUG_LOG_WAVFILES) + mutable ymfm_wavfile<1> m_wavfile[CHANNELS]; // for debugging +#endif +}; + +} + +#endif // YMFM_FM_H |