nuked.h

/* Nuked OPL3 emulator.
 *
 * Copyright (C) 2013-2020 Nuke.YKT
 * Copyright (C) 2026 Tony Gies (Nuked-OPL3-fast modifications)
 *
 * This file is part of Nuked OPL3.
 *
 * Nuked OPL3 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1
 * of the License, or (at your option) any later version.
 *
 * Nuked OPL3 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Nuked OPL3. If not, see <https://www.gnu.org/licenses/>.
 *
 * Thanks:
 *     MAME Development Team(Jarek Burczynski, Tatsuyuki Satoh):
 *         Feedback and Rhythm part calculation information.
 *     forums.submarine.org.uk(carbon14, opl3):
 *         Tremolo and phase generator calculation information.
 *     OPLx decapsulated(Matthew Gambrell, Olli Niemitalo):
 *         OPL2 ROMs.
 *     siliconpr0n.org(John McMaster, digshadow):
 *         YMF262 and VRC VII decaps and die shots.
 *
 * Upstream version: 1.8 (commit cfedb09)
 * Fork version:    1.8-fast.2
 * Fork home:       https://github.com/tgies/Nuked-OPL3-fast
 *
 * Nuked-OPL3-fast is a bit-exact performance-optimized fork of Nuked-OPL3.
 * Audio output is identical to upstream for the same register stream.
 */
 
#ifndef AUDIO_SOFTSYNTH_OPL_NUKED_H
#define AUDIO_SOFTSYNTH_OPL_NUKED_H
 
#include "common/scummsys.h"
#include "audio/fmopl.h"
 
#ifndef DISABLE_NUKED_OPL
 
#ifndef OPL_ENABLE_STEREOEXT
#define OPL_ENABLE_STEREOEXT 0
#endif
 
#ifndef OPL_QUIRK_CHANNELSAMPLEDELAY
#define OPL_QUIRK_CHANNELSAMPLEDELAY (!OPL_ENABLE_STEREOEXT)
#endif
 
#define OPL_WRITEBUF_SIZE   1024
#define OPL_WRITEBUF_DELAY  2
 
namespace OPL {
namespace NUKED {
 
typedef struct _opl3_slot opl3_slot;
typedef struct _opl3_channel opl3_channel;
typedef struct _opl3_chip opl3_chip;
 
struct _opl3_slot {
    opl3_channel *channel;
    opl3_chip *chip;
    int16_t *mod;
    uint8_t *trem;
    uint32_t pg_reset;
    uint32_t pg_phase;
    uint32_t pg_inc;
    int16_t out;
    int16_t fbmod;
    int16_t prout;
    uint16_t eg_rout;
    uint16_t eg_out;
    /* Cached (reg_tl << 2) + (eg_ksl >> kslshift[reg_ksl]); maintained by
     * OPL3_EnvelopeUpdateKSL whenever any of those inputs change. Hoists
     * a load + lookup + shift out of the per-sample envelope hot path. */
    uint16_t eg_tl_ksl;
    uint16_t pg_phase_out;
    uint8_t key;
    uint8_t eg_gen;
    uint8_t reg_vib;
    uint8_t reg_mult;
    uint8_t reg_wf;
    uint8_t slot_num;
    uint8_t eg_ksl;
    uint8_t eg_ks;
    uint8_t reg_type;
    uint8_t reg_ksr;
    uint8_t reg_ksl;
    uint8_t reg_tl;
    uint8_t reg_ar;
    uint8_t reg_dr;
    uint8_t reg_sl;
    uint8_t reg_rr;
    uint8_t eg_rates[4];
    uint8_t eg_rate_hi[4];
    uint8_t eg_rate_lo[4];
    /* Phase increment per vibrato position, maintained by
     * OPL3_PhaseUpdateInc (and rebuilt on vibshift changes); pg_inc_vib[pos]
     * equals the upstream per-sample vibrato f_num adjustment for that pos. */
    uint32_t pg_inc_vib[8];
};
 
struct _opl3_channel {
    opl3_slot *slotz[2];/*Don't use "slots" keyword to avoid conflict with Qt applications*/
    opl3_channel *pair;
    opl3_chip *chip;
    int16_t *out[4];
#if OPL_QUIRK_CHANNELSAMPLEDELAY
    /* Mix-pass pointer lists: identical to out[] except entries pointing at
     * a delayed slot's out are redirected to its prout, which holds the
     * previous sample's out once all 36 slots are processed. out_left delays
     * slots 15-35 and out_right delays 33-35, reproducing the
     * CHANNELSAMPLEDELAY snapshots without staging slot processing around
     * the mixes. */
    int16_t *out_left[4];
    int16_t *out_right[4];
#endif
    uint8_t out_cnt;
 
#if OPL_ENABLE_STEREOEXT
    int32_t leftpan;
    int32_t rightpan;
#endif
 
    uint8_t chtype;
    uint16_t f_num;
    uint8_t block;
    uint8_t fb;
    uint8_t con;
    uint8_t alg;
    uint8_t ksv;
    uint16_t cha, chb;
    uint16_t chc, chd;
    uint8_t ch_num;
};
 
typedef struct _opl3_writebuf {
    uint64_t time;
    uint16_t reg;
    uint8_t data;
} opl3_writebuf;
 
struct _opl3_chip {
    opl3_channel channel[18];
    opl3_slot slot[36];
    uint16_t timer;
    uint64_t eg_timer;
    uint8_t eg_timerrem;
    uint8_t eg_state;
    uint8_t eg_add;
    uint8_t eg_timer_lo;
    uint8_t newm;
    uint8_t nts;
    uint8_t rhy;
    uint8_t vibpos;
    uint8_t vibshift;
    uint8_t tremolo;
    uint8_t tremolopos;
    uint8_t tremoloshift;
    uint8_t tremolo_dirty;
    uint32_t noise;
    /* Bit 0 of the noise LFSR state as seen by the hh (slot 13) and sd
     * (slot 16) rhythm operators, precomputed per sample */
    uint32_t noise_hh;
    uint32_t noise_sd;
    int16_t zeromod;
    int32_t mixbuff[4];
    uint8_t rm_hh_bit2;
    uint8_t rm_hh_bit3;
    uint8_t rm_hh_bit7;
    uint8_t rm_hh_bit8;
    uint8_t rm_tc_bit3;
    uint8_t rm_tc_bit5;
 
#if OPL_ENABLE_STEREOEXT
    uint8_t stereoext;
#endif
 
    /* OPL3L */
    int32_t rateratio;
    int32_t samplecnt;
    int16_t oldsamples[4];
    int16_t samples[4];
 
    uint64_t writebuf_samplecnt;
    uint32_t writebuf_cur;
    uint32_t writebuf_last;
    uint64_t writebuf_lasttime;
    opl3_writebuf writebuf[OPL_WRITEBUF_SIZE];
};
 
void OPL3_Generate(opl3_chip *chip, int16_t *buf);
void OPL3_GenerateResampled(opl3_chip *chip, int16_t *buf);
void OPL3_Reset(opl3_chip *chip, uint32_t samplerate);
void OPL3_WriteReg(opl3_chip *chip, uint16_t reg, uint8_t v);
void OPL3_WriteRegBuffered(opl3_chip *chip, uint16_t reg, uint8_t v);
void OPL3_GenerateStream(opl3_chip *chip, int16_t *sndptr, uint32_t numsamples);
 
void OPL3_Generate4Ch(opl3_chip *chip, int16_t *buf4);
void OPL3_Generate4ChResampled(opl3_chip *chip, int16_t *buf4);
void OPL3_Generate4ChStream(opl3_chip *chip, int16_t *sndptr1, int16_t *sndptr2, uint32_t numsamples);
 
class OPL : public ::OPL::OPL, public Audio::EmulatedChip {
private:
    Config::OplType _type;
    uint _rate;
    opl3_chip chip;
    uint address[2];
    void dualWrite(uint8 index, uint8 reg, uint8 val);
 
public:
    OPL(Config::OplType type);
    ~OPL();
 
    bool init() override;
    void reset() override;
 
    void write(int a, int v) override;
 
    void writeReg(int r, int v) override;
 
    bool isStereo() const override { return true; }
 
protected:
    void generateSamples(int16 *buffer, int length) override;
};
 
}
}
 
#endif // !DISABLE_NUKED_OPL
 
#endif