202 lines
6.4 KiB
C
202 lines
6.4 KiB
C
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/*
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* Copyright (C) 2002-2010 The DOSBox Team
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* OPL2/OPL3 emulation library
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/*
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* Originally based on ADLIBEMU.C, an AdLib/OPL2 emulation library by Ken Silverman
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* Copyright (C) 1998-2001 Ken Silverman
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* Ken Silverman's official web site: "http://www.advsys.net/ken"
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*/
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#define fltype double
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/*
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define Bits, Bitu, Bit32s, Bit32u, Bit16s, Bit16u, Bit8s, Bit8u here
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*/
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/*
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#include <stdint.h>
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typedef uintptr_t Bitu;
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typedef intptr_t Bits;
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typedef uint32_t Bit32u;
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typedef int32_t Bit32s;
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typedef uint16_t Bit16u;
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typedef int16_t Bit16s;
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typedef uint8_t Bit8u;
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typedef int8_t Bit8s;
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*/
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/*
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define attribution that inlines/forces inlining of a function (optional)
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*/
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#define OPL_INLINE INLINE
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#undef NUM_CHANNELS
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#if defined(OPLTYPE_IS_OPL3)
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#define NUM_CHANNELS 18
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#else
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#define NUM_CHANNELS 9
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#endif
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#define MAXOPERATORS (NUM_CHANNELS*2)
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#define FL05 ((fltype)0.5)
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#define FL2 ((fltype)2.0)
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#define PI ((fltype)3.1415926535897932384626433832795)
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#define FIXEDPT 0x10000 // fixed-point calculations using 16+16
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#define FIXEDPT_LFO 0x1000000 // fixed-point calculations using 8+24
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#define WAVEPREC 1024 // waveform precision (10 bits)
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#define INTFREQU ((fltype)(14318180.0 / 288.0)) // clocking of the chip
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#define OF_TYPE_ATT 0
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#define OF_TYPE_DEC 1
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#define OF_TYPE_REL 2
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#define OF_TYPE_SUS 3
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#define OF_TYPE_SUS_NOKEEP 4
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#define OF_TYPE_OFF 5
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#define ARC_CONTROL 0x00
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#define ARC_TVS_KSR_MUL 0x20
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#define ARC_KSL_OUTLEV 0x40
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#define ARC_ATTR_DECR 0x60
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#define ARC_SUSL_RELR 0x80
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#define ARC_FREQ_NUM 0xa0
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#define ARC_KON_BNUM 0xb0
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#define ARC_PERC_MODE 0xbd
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#define ARC_FEEDBACK 0xc0
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#define ARC_WAVE_SEL 0xe0
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#define ARC_SECONDSET 0x100 // second operator set for OPL3
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#define OP_ACT_OFF 0x00
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#define OP_ACT_NORMAL 0x01 // regular channel activated (bitmasked)
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#define OP_ACT_PERC 0x02 // percussion channel activated (bitmasked)
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#define BLOCKBUF_SIZE 512
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// vibrato constants
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#define VIBTAB_SIZE 8
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#define VIBFAC 70/50000 // no braces, integer mul/div
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// tremolo constants and table
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#define TREMTAB_SIZE 53
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#define TREM_FREQ ((fltype)(3.7)) // tremolo at 3.7hz
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/* operator struct definition
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For OPL2 all 9 channels consist of two operators each, carrier and modulator.
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Channel x has operators x as modulator and operators (9+x) as carrier.
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For OPL3 all 18 channels consist either of two operators (2op mode) or four
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operators (4op mode) which is determined through register4 of the second
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adlib register set.
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Only the channels 0,1,2 (first set) and 9,10,11 (second set) can act as
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4op channels. The two additional operators for a channel y come from the
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2op channel y+3 so the operatorss y, (9+y), y+3, (9+y)+3 make up a 4op
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channel.
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*/
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typedef struct operator_struct {
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Bit32s cval, lastcval; // current output/last output (used for feedback)
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Bit32u tcount, wfpos, tinc; // time (position in waveform) and time increment
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fltype amp, step_amp; // and amplification (envelope)
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fltype vol; // volume
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fltype sustain_level; // sustain level
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Bit32s mfbi; // feedback amount
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fltype a0, a1, a2, a3; // attack rate function coefficients
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fltype decaymul, releasemul; // decay/release rate functions
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Bit32u op_state; // current state of operator (attack/decay/sustain/release/off)
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Bit32u toff;
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Bit32s freq_high; // highest three bits of the frequency, used for vibrato calculations
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Bit16s* cur_wform; // start of selected waveform
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Bit32u cur_wmask; // mask for selected waveform
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Bit32u act_state; // activity state (regular, percussion)
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bool sus_keep; // keep sustain level when decay finished
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bool vibrato,tremolo; // vibrato/tremolo enable bits
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// variables used to provide non-continuous envelopes
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Bit32u generator_pos; // for non-standard sample rates we need to determine how many samples have passed
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Bits cur_env_step; // current (standardized) sample position
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Bits env_step_a,env_step_d,env_step_r; // number of std samples of one step (for attack/decay/release mode)
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Bit8u step_skip_pos_a; // position of 8-cyclic step skipping (always 2^x to check against mask)
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Bits env_step_skip_a; // bitmask that determines if a step is skipped (respective bit is zero then)
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#if defined(OPLTYPE_IS_OPL3)
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bool is_4op,is_4op_attached; // base of a 4op channel/part of a 4op channel
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Bit32s left_pan,right_pan; // opl3 stereo panning amount
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#endif
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} op_type;
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// per-chip variables
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Bitu chip_num;
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op_type op[MAXOPERATORS];
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Bits int_samplerate;
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Bit8u status;
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Bit32u opl_index;
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#if defined(OPLTYPE_IS_OPL3)
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Bit8u adlibreg[512]; // adlib register set (including second set)
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Bit8u wave_sel[44]; // waveform selection
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#else
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Bit8u adlibreg[256]; // adlib register set
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Bit8u wave_sel[22]; // waveform selection
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#endif
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// vibrato/tremolo increment/counter
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Bit32u vibtab_pos;
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Bit32u vibtab_add;
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Bit32u tremtab_pos;
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Bit32u tremtab_add;
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// enable an operator
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void enable_operator(Bitu regbase, op_type* op_pt);
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// functions to change parameters of an operator
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void change_frequency(Bitu chanbase, Bitu regbase, op_type* op_pt);
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void change_attackrate(Bitu regbase, op_type* op_pt);
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void change_decayrate(Bitu regbase, op_type* op_pt);
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void change_releaserate(Bitu regbase, op_type* op_pt);
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void change_sustainlevel(Bitu regbase, op_type* op_pt);
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void change_waveform(Bitu regbase, op_type* op_pt);
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void change_keepsustain(Bitu regbase, op_type* op_pt);
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void change_vibrato(Bitu regbase, op_type* op_pt);
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void change_feedback(Bitu chanbase, op_type* op_pt);
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// general functions
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void adlib_init(Bit32u samplerate);
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void adlib_write(Bitu idx, Bit8u val);
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void adlib_getsample(Bit16s* sndptr, Bits numsamples);
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Bitu adlib_reg_read(Bitu port);
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void adlib_write_index(Bitu port, Bit8u val);
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static Bit32u generator_add; // should be a chip parameter
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