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Port of cosmo-engine to TempleOS
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cosmo-engine/Opl.HC

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/*
* Copyright (C) 2002-2017 The DOSBox Team
* OPL2/OPL3 emulation library
*
* This library 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.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* Originally based on ADLIBEMU.C, an AdLib/OPL2 emulation library by Ken Silverman
* Copyright (C) 1998-2001 Ken Silverman
* Ken Silverman's official web site: "http://www.advsys.net/ken"
*/
/*
* Converted to HolyC by Alec Murphy, 2020-04-04
*/
#define NUM_CHANNELS 9
#define MAXOPERATORS NUM_CHANNELS*2
#define FL05 0.5
#define FL2 2.0
#define PI pi
#define FIXEDPT 0x10000 // fixed-point calculations using 16+16
#define FIXEDPT_LFO 0x1000000 // fixed-point calculations using 8+24
#define WAVEPREC 1024 // waveform precision (10 bits)
#define INTFREQU 14318180.0 / 288.0 // clocking of the chip
#define OF_TYPE_ATT 0
#define OF_TYPE_DEC 1
#define OF_TYPE_REL 2
#define OF_TYPE_SUS 3
#define OF_TYPE_SUS_NOKEEP 4
#define OF_TYPE_OFF 5
#define ARC_CONTROL 0x00
#define ARC_TVS_KSR_MUL 0x20
#define ARC_KSL_OUTLEV 0x40
#define ARC_ATTR_DECR 0x60
#define ARC_SUSL_RELR 0x80
#define ARC_FREQ_NUM 0xa0
#define ARC_KON_BNUM 0xb0
#define ARC_PERC_MODE 0xbd
#define ARC_FEEDBACK 0xc0
#define ARC_WAVE_SEL 0xe0
#define ARC_SECONDSET 0x100 // second operator set for OPL3
#define OP_ACT_OFF 0x00
#define OP_ACT_NORMAL 0x01 // regular channel activated (bitmasked)
#define OP_ACT_PERC 0x02 // percussion channel activated (bitmasked)
#define BLOCKBUF_SIZE 512
// vibrato constants
#define VIBTAB_SIZE 8
#define VIBFAC 70/50000 // no braces, integer mul/div
// tremolo constants and table
#define TREMTAB_SIZE 53
#define TREM_FREQ 3.7 // tremolo at 3.7hz
#define Bitu U64
#define Bits I64
#define Bit32u U32
#define Bit32s I32
#define Bit16u U16
#define Bit16s I16
#define Bit8u U8
#define Bit8s I8
#define fltype F64
class op_type {
Bit32s cval, lastcval; // current output/last output (used for feedback)
Bit32u tcount, wfpos, tinc; // time (position in waveform) and time increment
fltype amp, step_amp; // and amplification (envelope)
fltype vol; // volume
fltype sustain_level; // sustain level
Bit32s mfbi; // feedback amount
fltype a0, a1, a2, a3; // attack rate function coefficients
fltype decaymul, releasemul; // decay/release rate functions
Bit32u op_state; // current state of operator (attack/decay/sustain/release/off)
Bit32u toff;
Bit32s freq_high; // highest three bits of the frequency, used for vibrato calculations
Bit16s* cur_wform; // start of selected waveform
Bit32u cur_wmask; // mask for selected waveform
Bit32u act_state; // activity state (regular, percussion)
Bool sus_keep; // keep sustain level when decay finished
Bool vibrato,tremolo; // vibrato/tremolo enable bits
// variables used to provide non-continuous envelopes
Bit32u generator_pos; // for non-standard sample rates we need to determine how many samples have passed
Bits cur_env_step; // current (standardized) sample position
Bits env_step_a,env_step_d,env_step_r; // number of std samples of one step (for attack/decay/release mode)
Bit8u step_skip_pos_a; // position of 8-cyclic step skipping (always 2^x to check against mask)
Bits env_step_skip_a; // bitmask that determines if a step is skipped (respective bit is zero then)
};
Bit32u generator_add; // should be a chip parameter
// per-chip variables
Bitu chip_num;
op_type op[MAXOPERATORS];
Bits int_samplerate;
Bit8u status;
Bit32u opl_index;
Bit8u adlibreg[256]; // adlib register set
Bit8u wave_sel[22]; // waveform selection
// vibrato/tremolo increment/counter
Bit32u vibtab_pos;
Bit32u vibtab_add;
Bit32u tremtab_pos;
Bit32u tremtab_add;
fltype recipsamp; // inverse of sampling rate
Bit16s wavtable[WAVEPREC*3]; // wave form table
// vibrato/tremolo tables
Bit32s vib_table[VIBTAB_SIZE];
Bit32s trem_table[TREMTAB_SIZE*2];
Bit32s vibval_const[BLOCKBUF_SIZE];
Bit32s tremval_const[BLOCKBUF_SIZE];
// vibrato value tables (used per-operator)
Bit32s vibval_var1[BLOCKBUF_SIZE];
Bit32s vibval_var2[BLOCKBUF_SIZE];
//Bit32s vibval_var3[BLOCKBUF_SIZE];
//Bit32s vibval_var4[BLOCKBUF_SIZE];
// vibrato/trmolo value table pointers
Bit32s *vibval1, *vibval2, *vibval3, *vibval4;
Bit32s *tremval1, *tremval2, *tremval3, *tremval4;
// key scale level lookup table
fltype kslmul[4] = {
0.0, 0.5, 0.25, 1.0 // -> 0, 3, 1.5, 6 dB/oct
};
// frequency multiplicator lookup table
fltype frqmul_tab[16] = {
0.5,1,2,3,4,5,6,7,8,9,10,10,12,12,15,15
};
// calculated frequency multiplication values (depend on sampling rate)
fltype frqmul[16];
// key scale levels
Bit8u kslev[8][16];
// map a channel number to the register offset of the modulator (=register base)
Bit8u modulatorbase[9] = {
0,1,2,
8,9,10,
16,17,18
};
// map a register base to a modulator operator number or operator number
Bit8u regbase2modop[22] = {
0,1,2,0,1,2,0,0,3,4,5,3,4,5,0,0,6,7,8,6,7,8
};
Bit8u regbase2op[22] = {
0,1,2,9,10,11,0,0,3,4,5,12,13,14,0,0,6,7,8,15,16,17
};
// start of the waveform
Bit32u waveform[8] = {
WAVEPREC,
WAVEPREC>>1,
WAVEPREC,
(WAVEPREC*3)>>2,
0,
0,
(WAVEPREC*5)>>2,
WAVEPREC<<1
};
// length of the waveform as mask
Bit32u wavemask[8] = {
WAVEPREC-1,
WAVEPREC-1,
(WAVEPREC>>1)-1,
(WAVEPREC>>1)-1,
WAVEPREC-1,
((WAVEPREC*3)>>2)-1,
WAVEPREC>>1,
WAVEPREC-1
};
// where the first entry resides
Bit32u wavestart[8] = {
0,
WAVEPREC>>1,
0,
WAVEPREC>>2,
0,
0,
0,
WAVEPREC>>3
};
// envelope generator function constants
fltype attackconst[4] = {
(1/2.82624),
(1/2.25280),
(1/1.88416),
(1/1.59744)
};
fltype decrelconst[4] = {
(1/39.28064),
(1/31.41608),
(1/26.17344),
(1/22.44608)
};
U0 operator_advance(op_type* op_pt, Bit32s vib) {
op_pt->wfpos = op_pt->tcount; // waveform position
// advance waveform time
op_pt->tcount += op_pt->tinc;
op_pt->tcount += (op_pt->tinc)*vib/FIXEDPT;
op_pt->generator_pos += generator_add;
}
U0 operator_advance_drums(op_type* op_pt1, Bit32s vib1, op_type* op_pt2, Bit32s vib2, op_type* op_pt3, Bit32s vib3) {
Bit32u c1 = op_pt1->tcount/FIXEDPT;
Bit32u c3 = op_pt3->tcount/FIXEDPT;
Bit32u phasebit = Cond((((c1 & 0x88) ^ ((c1<<5) & 0x80)) | ((c3 ^ (c3<<2)) & 0x20)), 0x02, 0x00);
Bit32u noisebit = RandU64()&1;
Bit32u snare_phase_bit = ((((op_pt1->tcount/FIXEDPT) / 0x100))&1);
//Hihat
Bit32u inttm = (phasebit<<8) | (0x34<<(phasebit ^ (noisebit<<1)));
op_pt1->wfpos = inttm*FIXEDPT; // waveform position
// advance waveform time
op_pt1->tcount += op_pt1->tinc;
op_pt1->tcount += (op_pt1->tinc)*vib1/FIXEDPT;
op_pt1->generator_pos += generator_add;
//Snare
inttm = ((1+snare_phase_bit) ^ noisebit)<<8;
op_pt2->wfpos = inttm*FIXEDPT; // waveform position
// advance waveform time
op_pt2->tcount += op_pt2->tinc;
op_pt2->tcount += (op_pt2->tinc)*vib2/FIXEDPT;
op_pt2->generator_pos += generator_add;
//Cymbal
inttm = (1+phasebit)<<8;
op_pt3->wfpos = inttm*FIXEDPT; // waveform position
// advance waveform time
op_pt3->tcount += op_pt3->tinc;
op_pt3->tcount += (op_pt3->tinc)*vib3/FIXEDPT;
op_pt3->generator_pos += generator_add;
}
// output level is sustained, mode changes only when operator is turned off (->release)
// or when the keep-sustained bit is turned off (->sustain_nokeep)
U0 operator_output(op_type* op_pt, Bit32s modulator, Bit32s trem) {
if (op_pt->op_state != OF_TYPE_OFF) {
op_pt->lastcval = op_pt->cval;
Bit32u i = ((op_pt->wfpos+modulator)/FIXEDPT);
// wform: -16384 to 16383 (0x4000)
// trem : 32768 to 65535 (0x10000)
// step_amp: 0.0 to 1.0
// vol : 1/2^14 to 1/2^29 (/0x4000; /1../0x8000)
op_pt->cval = (op_pt->step_amp*op_pt->vol*op_pt->cur_wform[i&op_pt->cur_wmask]*trem/16.0);
}
}
// no action, operator is off
U0 operator_off(op_type* op_pt) {
}
// output level is sustained, mode changes only when operator is turned off (->release)
// or when the keep-sustained bit is turned off (->sustain_nokeep)
U0 operator_sustain(op_type* op_pt) {
Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT; // number of (standardized) samples
Bit32u ct;
for (ct=0; ct<num_steps_add; ct++) {
op_pt->cur_env_step++;
}
op_pt->generator_pos -= num_steps_add*FIXEDPT;
}
// operator in release mode, if output level reaches zero the operator is turned off
U0 operator_release(op_type* op_pt) {
// ??? boundary?
if (op_pt->amp > 0.00000001) {
// release phase
op_pt->amp *= op_pt->releasemul;
}
Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT; // number of (standardized) samples
Bit32u ct;
for (ct=0; ct<num_steps_add; ct++) {
op_pt->cur_env_step++; // sample counter
if ((op_pt->cur_env_step & op_pt->env_step_r)==0) {
if (op_pt->amp <= 0.00000001) {
// release phase finished, turn off this operator
op_pt->amp = 0.0;
if (op_pt->op_state == OF_TYPE_REL) {
op_pt->op_state = OF_TYPE_OFF;
}
}
op_pt->step_amp = op_pt->amp;
}
}
op_pt->generator_pos -= num_steps_add*FIXEDPT;
}
// operator in decay mode, if sustain level is reached the output level is either
// kept (sustain level keep enabled) or the operator is switched into release mode
U0 operator_decay(op_type* op_pt) {
if (op_pt->amp > op_pt->sustain_level) {
// decay phase
op_pt->amp *= op_pt->decaymul;
}
Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT; // number of (standardized) samples
Bit32u ct;
for (ct=0; ct<num_steps_add; ct++) {
op_pt->cur_env_step++;
if ((op_pt->cur_env_step & op_pt->env_step_d)==0) {
if (op_pt->amp <= op_pt->sustain_level) {
// decay phase finished, sustain level reached
if (op_pt->sus_keep) {
// keep sustain level (until turned off)
op_pt->op_state = OF_TYPE_SUS;
op_pt->amp = op_pt->sustain_level;
} else {
// next: release phase
op_pt->op_state = OF_TYPE_SUS_NOKEEP;
}
}
op_pt->step_amp = op_pt->amp;
}
}
op_pt->generator_pos -= num_steps_add*FIXEDPT;
}
// operator in attack mode, if full output level is reached,
// the operator is switched into decay mode
U0 operator_attack(op_type* op_pt) {
op_pt->amp = ((op_pt->a3*op_pt->amp + op_pt->a2)*op_pt->amp + op_pt->a1)*op_pt->amp + op_pt->a0;
Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT; // number of (standardized) samples
Bit32u ct;
for (ct=0; ct<num_steps_add; ct++) {
op_pt->cur_env_step++; // next sample
if ((op_pt->cur_env_step & op_pt->env_step_a)==0) { // check if next step already reached
if (op_pt->amp > 1.0) {
// attack phase finished, next: decay
op_pt->op_state = OF_TYPE_DEC;
op_pt->amp = 1.0;
op_pt->step_amp = 1.0;
}
op_pt->step_skip_pos_a <<= 1;
if (op_pt->step_skip_pos_a==0) op_pt->step_skip_pos_a = 1;
if (op_pt->step_skip_pos_a & op_pt->env_step_skip_a) { // check if required to skip next step
op_pt->step_amp = op_pt->amp;
}
}
}
op_pt->generator_pos -= num_steps_add*FIXEDPT;
}
Bit8u step_skip_mask[5] = {0xff, 0xfe, 0xee, 0xba, 0xaa};
U0 change_attackrate(Bitu regbase, op_type* op_pt) {
Bits attackrate = adlibreg[ARC_ATTR_DECR+regbase]>>4;
if (attackrate) {
fltype f = (Pow(FL2,attackrate+(op_pt->toff>>2)-1)*attackconst[op_pt->toff&3]*recipsamp);
// attack rate coefficients
op_pt->a0 = (0.0377*f);
op_pt->a1 = (10.73*f+1);
op_pt->a2 = (-17.57*f);
op_pt->a3 = (7.42*f);
Bits step_skip = attackrate*4 + op_pt->toff;
Bits steps = step_skip >> 2;
op_pt->env_step_a = (1<<Cond(steps<=12,12-steps,0))-1;
Bits step_num = Cond((step_skip<=48),(4-(step_skip&3)),0);
op_pt->env_step_skip_a = step_skip_mask[step_num];
if (step_skip>=62) {
op_pt->a0 = (2.0); // something that triggers an immediate transition to amp:=1.0
op_pt->a1 = (0.0);
op_pt->a2 = (0.0);
op_pt->a3 = (0.0);
}
} else {
// attack disabled
op_pt->a0 = 0.0;
op_pt->a1 = 1.0;
op_pt->a2 = 0.0;
op_pt->a3 = 0.0;
op_pt->env_step_a = 0;
op_pt->env_step_skip_a = 0;
}
}
U0 change_decayrate(Bitu regbase, op_type* op_pt) {
Bits decayrate = adlibreg[ARC_ATTR_DECR+regbase]&15;
// decaymul should be 1.0 when decayrate==0
if (decayrate) {
fltype f = (-7.4493*decrelconst[op_pt->toff&3]*recipsamp);
op_pt->decaymul = (Pow(FL2,f*Pow(FL2,(decayrate+(op_pt->toff>>2)))));
Bits steps = (decayrate*4 + op_pt->toff) >> 2;
op_pt->env_step_d = (1<<Cond(steps<=12,12-steps,0))-1;
} else {
op_pt->decaymul = 1.0;
op_pt->env_step_d = 0;
}
}
U0 change_releaserate(Bitu regbase, op_type* op_pt) {
Bits releaserate = adlibreg[ARC_SUSL_RELR+regbase]&15;
// releasemul should be 1.0 when releaserate==0
if (releaserate) {
fltype f = (-7.4493*decrelconst[op_pt->toff&3]*recipsamp);
op_pt->releasemul = (Pow(FL2,f*Pow(FL2,(releaserate+(op_pt->toff>>2)))));
Bits steps = (releaserate*4 + op_pt->toff) >> 2;
op_pt->env_step_r = (1<<Cond(steps<=12,12-steps,0))-1;
} else {
op_pt->releasemul = 1.0;
op_pt->env_step_r = 0;
}
}
U0 change_sustainlevel(Bitu regbase, op_type* op_pt) {
Bits sustainlevel = adlibreg[ARC_SUSL_RELR+regbase]>>4;
// sustainlevel should be 0.0 when sustainlevel==15 (max)
if (sustainlevel<15) {
op_pt->sustain_level = (Pow(FL2,sustainlevel * (-FL05)));
} else {
op_pt->sustain_level = 0.0;
}
}
U0 change_waveform(Bitu regbase, op_type* op_pt) {
// waveform selection
op_pt->cur_wmask = wavemask[wave_sel[regbase]];
op_pt->cur_wform = &wavtable[waveform[wave_sel[regbase]]];
// (might need to be adapted to waveform type here...)
}
U0 change_keepsustain(Bitu regbase, op_type* op_pt) {
op_pt->sus_keep = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x20)>0;
if (op_pt->op_state==OF_TYPE_SUS) {
if (!op_pt->sus_keep) op_pt->op_state = OF_TYPE_SUS_NOKEEP;
} else if (op_pt->op_state==OF_TYPE_SUS_NOKEEP) {
if (op_pt->sus_keep) op_pt->op_state = OF_TYPE_SUS;
}
}
// enable/disable vibrato/tremolo LFO effects
U0 change_vibrato(Bitu regbase, op_type* op_pt) {
op_pt->vibrato = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x40)!=0;
op_pt->tremolo = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x80)!=0;
}
// change amount of self-feedback
U0 change_feedback(Bitu chanbase, op_type* op_pt) {
Bits feedback = adlibreg[ARC_FEEDBACK+chanbase]&14;
if (feedback) op_pt->mfbi = (Pow(FL2,((feedback>>1)+8)));
else op_pt->mfbi = 0;
}
U0 change_frequency(Bitu chanbase, Bitu regbase, op_type* op_pt) {
// frequency
Bit32u frn = (((adlibreg[ARC_KON_BNUM+chanbase])&3)<<8) + adlibreg[ARC_FREQ_NUM+chanbase];
// block number/octave
Bit32u oct = (((adlibreg[ARC_KON_BNUM+chanbase])>>2)&7);
op_pt->freq_high = ((frn>>7)&7);
// keysplit
Bit32u note_sel = (adlibreg[8]>>6)&1;
op_pt->toff = ((frn>>9)&(note_sel^1)) | ((frn>>8)&note_sel);
op_pt->toff += (oct<<1);
// envelope scaling (KSR)
if (!(adlibreg[ARC_TVS_KSR_MUL+regbase]&0x10)) op_pt->toff >>= 2;
// 20+a0+b0:
op_pt->tinc = ((((frn<<oct))*frqmul[adlibreg[ARC_TVS_KSR_MUL+regbase]&15]));
// 40+a0+b0:
fltype vol_in = ((adlibreg[ARC_KSL_OUTLEV+regbase]&63) +
kslmul[adlibreg[ARC_KSL_OUTLEV+regbase]>>6]*kslev[oct][frn>>6]);
op_pt->vol = (Pow(FL2,(vol_in * -0.125 - 14)));
// operator frequency changed, care about features that depend on it
change_attackrate(regbase,op_pt);
change_decayrate(regbase,op_pt);
change_releaserate(regbase,op_pt);
}
U0 enable_operator(Bitu regbase, op_type* op_pt, Bit32u act_type) {
// check if this is really an off-on transition
if (op_pt->act_state == OP_ACT_OFF) {
Bits wselbase = regbase;
if (wselbase>=ARC_SECONDSET) wselbase -= (ARC_SECONDSET-22); // second set starts at 22
op_pt->tcount = wavestart[wave_sel[wselbase]]*FIXEDPT;
// start with attack mode
op_pt->op_state = OF_TYPE_ATT;
op_pt->act_state |= act_type;
}
}
U0 disable_operator(op_type* op_pt, Bit32u act_type) {
// check if this is really an on-off transition
if (op_pt->act_state != OP_ACT_OFF) {
op_pt->act_state &= (~act_type);
if (op_pt->act_state == OP_ACT_OFF) {
if (op_pt->op_state != OF_TYPE_OFF) op_pt->op_state = OF_TYPE_REL;
}
}
}
U0 adlib_init(Bit32u samplerate) {
Bits i, j, oct;
int_samplerate = samplerate;
generator_add = (INTFREQU*FIXEDPT/int_samplerate);
MemSet(adlibreg,0,sizeof(adlibreg));
MemSet(op,0,sizeof(op_type)*MAXOPERATORS);
MemSet(wave_sel,0,sizeof(wave_sel));
for (i=0;i<MAXOPERATORS;i++) {
op[i].op_state = OF_TYPE_OFF;
op[i].act_state = OP_ACT_OFF;
op[i].amp = 0.0;
op[i].step_amp = 0.0;
op[i].vol = 0.0;
op[i].tcount = 0;
op[i].tinc = 0;
op[i].toff = 0;
op[i].cur_wmask = wavemask[0];
op[i].cur_wform = &wavtable[waveform[0]];
op[i].freq_high = 0;
op[i].generator_pos = 0;
op[i].cur_env_step = 0;
op[i].env_step_a = 0;
op[i].env_step_d = 0;
op[i].env_step_r = 0;
op[i].step_skip_pos_a = 0;
op[i].env_step_skip_a = 0;
}
recipsamp = 1.0 / int_samplerate;
for (i=15;i>=0;i--) {
frqmul[i] = (frqmul_tab[i]*INTFREQU/WAVEPREC*FIXEDPT*recipsamp);
}
status = 0;
opl_index = 0;
// create vibrato table
vib_table[0] = 8;
vib_table[1] = 4;
vib_table[2] = 0;
vib_table[3] = -4;
for (i=4; i<VIBTAB_SIZE; i++) vib_table[i] = vib_table[i-4]*-1;
// vibrato at ~6.1 ?? (opl3 docs say 6.1, opl4 docs say 6.0, y8950 docs say 6.4)
vibtab_add = (VIBTAB_SIZE*FIXEDPT_LFO/8192*INTFREQU/int_samplerate);
vibtab_pos = 0;
for (i=0; i<BLOCKBUF_SIZE; i++) vibval_const[i] = 0;
// create tremolo table
Bit32s trem_table_int[TREMTAB_SIZE];
for (i=0; i<14; i++) trem_table_int[i] = i-13; // upwards (13 to 26 -> -0.5/6 to 0)
for (i=14; i<41; i++) trem_table_int[i] = -i+14; // downwards (26 to 0 -> 0 to -1/6)
for (i=41; i<53; i++) trem_table_int[i] = i-40-26; // upwards (1 to 12 -> -1/6 to -0.5/6)
for (i=0; i<TREMTAB_SIZE; i++) {
// 0.0 .. -26/26*4.8/6 == [0.0 .. -0.8], 4/53 steps == [1 .. 0.57]
fltype trem_val1=((trem_table_int[i])*4.8/26.0/6.0); // 4.8db
fltype trem_val2=(((trem_table_int[i]/4))*1.2/6.0/6.0); // 1.2db (larger stepping)
trem_table[i] = (Pow(FL2,trem_val1)*FIXEDPT);
trem_table[TREMTAB_SIZE+i] = (Pow(FL2,trem_val2)*FIXEDPT);
}
// tremolo at 3.7hz
tremtab_add = (TREMTAB_SIZE * TREM_FREQ * FIXEDPT_LFO / int_samplerate);
tremtab_pos = 0;
for (i=0; i<BLOCKBUF_SIZE; i++) tremval_const[i] = FIXEDPT;
Bitu initfirstime = 0;
if (!initfirstime) {
initfirstime = 1;
// create waveform tables
for (i=0;i<(WAVEPREC>>1);i++) {
wavtable[(i<<1) +WAVEPREC] = (16384*Sin(((i<<1) )*PI*2/WAVEPREC));
wavtable[(i<<1)+1+WAVEPREC] = (16384*Sin(((i<<1)+1)*PI*2/WAVEPREC));
wavtable[i] = wavtable[(i<<1) +WAVEPREC];
// alternative: (zero-less)
/* wavtable[(i<<1) +WAVEPREC] = (16384*sin(((i<<2)+1)*PI/WAVEPREC));
wavtable[(i<<1)+1+WAVEPREC] = (16384*sin(((i<<2)+3)*PI/WAVEPREC));
wavtable[i] = wavtable[(i<<1)-1+WAVEPREC]; */
}
for (i=0;i<(WAVEPREC>>3);i++) {
wavtable[i+(WAVEPREC<<1)] = wavtable[i+(WAVEPREC>>3)]-16384;
wavtable[i+((WAVEPREC*17)>>3)] = wavtable[i+(WAVEPREC>>2)]+16384;
}
// key scale level table verified ([table in book]*8/3)
kslev[7][0] = 0; kslev[7][1] = 24; kslev[7][2] = 32; kslev[7][3] = 37;
kslev[7][4] = 40; kslev[7][5] = 43; kslev[7][6] = 45; kslev[7][7] = 47;
kslev[7][8] = 48;
for (i=9;i<16;i++) kslev[7][i] = (i+41);
for (j=6;j>=0;j--) {
for (i=0;i<16;i++) {
oct = kslev[j+1][i]-8;
if (oct < 0) oct = 0;
kslev[j][i] = oct;
}
}
}
}
U0 adlib_write(Bitu idx, Bit8u val) {
Bit32u second_set = idx&0x100;
adlibreg[idx] = val;
I64 num;
Bitu base;
Bitu modop;
Bitu chanbase;
Bitu regbase;
Bits opbase;
Bits modbase;
op_type* op_ptr;
switch (idx&0xf0) {
case ARC_CONTROL:
// here we check for the second set registers, too:
switch (idx) {
case 0x02: // timer1 counter
case 0x03: // timer2 counter
break;
case 0x04:
// IRQ reset, timer mask/start
if (val&0x80) {
// clear IRQ bits in status register
status &= ~0x60;
} else {
status = 0;
}
break;
case 0x08:
// CSW, note select
break;
default:
break;
}
break;
case ARC_TVS_KSR_MUL:
case ARC_TVS_KSR_MUL+0x10: {
// tremolo/vibrato/sustain keeping enabled; key scale rate; frequency multiplication
num = idx&7;
base = (idx-ARC_TVS_KSR_MUL)&0xff;
if ((num<6) && (base<22)) {
modop = regbase2modop[Cond(second_set,(base+22),base)];
regbase = base+second_set;
chanbase = Cond(second_set,(modop-18+ARC_SECONDSET),modop);
// change tremolo/vibrato and sustain keeping of this operator
op_ptr = &op[modop+Cond((num<3), 0, 9)];
change_keepsustain(regbase,op_ptr);
change_vibrato(regbase,op_ptr);
// change frequency calculations of this operator as
// key scale rate and frequency multiplicator can be changed
change_frequency(chanbase,base,op_ptr);
}
}
break;
case ARC_KSL_OUTLEV:
case ARC_KSL_OUTLEV+0x10: {
// key scale level; output rate
num = idx&7;
base = (idx-ARC_KSL_OUTLEV)&0xff;
if ((num<6) && (base<22)) {
modop = regbase2modop[Cond(second_set,(base+22),base)];
chanbase = Cond(second_set,(modop-18+ARC_SECONDSET),modop);
// change frequency calculations of this operator as
// key scale level and output rate can be changed
op_ptr = &op[modop+Cond((num<3), 0, 9)];
change_frequency(chanbase,base,op_ptr);
}
}
break;
case ARC_ATTR_DECR:
case ARC_ATTR_DECR+0x10: {
// attack/decay rates
num = idx&7;
base = (idx-ARC_ATTR_DECR)&0xff;
if ((num<6) && (base<22)) {
regbase = base+second_set;
// change attack rate and decay rate of this operator
op_ptr = &op[regbase2op[Cond(second_set,(base+22),base)]];
change_attackrate(regbase,op_ptr);
change_decayrate(regbase,op_ptr);
}
}
break;
case ARC_SUSL_RELR:
case ARC_SUSL_RELR+0x10: {
// sustain level; release rate
num = idx&7;
base = (idx-ARC_SUSL_RELR)&0xff;
if ((num<6) && (base<22)) {
regbase = base+second_set;
// change sustain level and release rate of this operator
op_ptr = &op[regbase2op[Cond(second_set,(base+22),base)]];
change_releaserate(regbase,op_ptr);
change_sustainlevel(regbase,op_ptr);
}
}
break;
case ARC_FREQ_NUM: {
// 0xa0-0xa8 low8 frequency
base = (idx-ARC_FREQ_NUM)&0xff;
if (base<9) {
opbase = Cond(second_set,(base+18),base);
// regbase of modulator:
modbase = modulatorbase[base]+second_set;
chanbase = base+second_set;
change_frequency(chanbase,modbase,&op[opbase]);
change_frequency(chanbase,modbase+3,&op[opbase+9]);
}
}
break;
case ARC_KON_BNUM: {
if (idx == ARC_PERC_MODE) {
if ((val&0x30) == 0x30) { // BassDrum active
enable_operator(16,&op[6],OP_ACT_PERC);
change_frequency(6,16,&op[6]);
enable_operator(16+3,&op[6+9],OP_ACT_PERC);
change_frequency(6,16+3,&op[6+9]);
} else {
disable_operator(&op[6],OP_ACT_PERC);
disable_operator(&op[6+9],OP_ACT_PERC);
}
if ((val&0x28) == 0x28) { // Snare active
enable_operator(17+3,&op[16],OP_ACT_PERC);
change_frequency(7,17+3,&op[16]);
} else {
disable_operator(&op[16],OP_ACT_PERC);
}
if ((val&0x24) == 0x24) { // TomTom active
enable_operator(18,&op[8],OP_ACT_PERC);
change_frequency(8,18,&op[8]);
} else {
disable_operator(&op[8],OP_ACT_PERC);
}
if ((val&0x22) == 0x22) { // Cymbal active
enable_operator(18+3,&op[8+9],OP_ACT_PERC);
change_frequency(8,18+3,&op[8+9]);
} else {
disable_operator(&op[8+9],OP_ACT_PERC);
}
if ((val&0x21) == 0x21) { // Hihat active
enable_operator(17,&op[7],OP_ACT_PERC);
change_frequency(7,17,&op[7]);
} else {
disable_operator(&op[7],OP_ACT_PERC);
}
break;
}
// regular 0xb0-0xb8
base = (idx-ARC_KON_BNUM)&0xff;
if (base<9) {
opbase = Cond(second_set,(base+18),base);
// regbase of modulator:
modbase = modulatorbase[base]+second_set;
if (val&32) {
// operator switched on
enable_operator(modbase,&op[opbase],OP_ACT_NORMAL); // modulator (if 2op)
enable_operator(modbase+3,&op[opbase+9],OP_ACT_NORMAL); // carrier (if 2op)
} else {
// operator switched off
disable_operator(&op[opbase],OP_ACT_NORMAL);
disable_operator(&op[opbase+9],OP_ACT_NORMAL);
}
chanbase = base+second_set;
// change frequency calculations of modulator and carrier (2op) as
// the frequency of the channel has changed
change_frequency(chanbase,modbase,&op[opbase]);
change_frequency(chanbase,modbase+3,&op[opbase+9]);
}
}
break;
case ARC_FEEDBACK: {
// 0xc0-0xc8 feedback/modulation type (AM/FM)
base = (idx-ARC_FEEDBACK)&0xff;
if (base<9) {
opbase = Cond(second_set,(base+18),base);
chanbase = base+second_set;
change_feedback(chanbase,&op[opbase]);
}
}
break;
case ARC_WAVE_SEL:
case ARC_WAVE_SEL+0x10: {
num = idx&7;
base = (idx-ARC_WAVE_SEL)&0xff;
if ((num<6) && (base<22)) {
if (adlibreg[0x01]&0x20) {
// wave selection enabled, change waveform
wave_sel[base] = val&3;
op_ptr = &op[regbase2modop[base]+Cond((num<3), 0, 9)];
change_waveform(base,op_ptr);
}
}
}
break;
default:
break;
}
}
Bitu adlib_reg_read(Bitu port) {
// opl2-detection routines require ret&6 to be 6
if ((port&1)==0) {
return status|6;
}
return 0xff;
}
U0 adlib_write_index(Bitu port, Bit8u val) {
opl_index = val;
}
U0 clipit16(Bit32s ival, Bit16s* outval) {
if (ival<32768) {
if (ival>-32769) {
*outval=ival;
} else {
*outval = -32768;
}
} else {
*outval = 32767;
}
}
U0 (*opfuncs)(op_type*)[6] = {
&operator_attack,
&operator_decay,
&operator_release,
&operator_sustain, // sustain phase (keeping level)
&operator_release, // sustain_nokeep phase (release-style)
&operator_off
};
U0 adlib_getsample(Bit8u* sndptr, Bits numsamples, Bit8u is_stereo_output) {
Bits i, endsamples;
op_type* cptr;
Bit32s outbufl[BLOCKBUF_SIZE];
// vibrato/tremolo lookup tables (global, to possibly be used by all operators)
Bit32s vib_lut[BLOCKBUF_SIZE];
Bit32s trem_lut[BLOCKBUF_SIZE];
Bits samples_to_process = numsamples;
Bits cursmp;
Bit32s chanval;
for (cursmp=0; cursmp<samples_to_process; cursmp+=endsamples) {
endsamples = samples_to_process-cursmp;
if (endsamples>BLOCKBUF_SIZE) endsamples = BLOCKBUF_SIZE;
MemSet(&outbufl,0,endsamples*sizeof(Bit32s));
// calculate vibrato/tremolo lookup tables
Bit32s vib_tshift = Cond(((adlibreg[ARC_PERC_MODE]&0x40)==0), 1, 0); // 14cents/7cents switching
for (i=0;i<endsamples;i++) {
// cycle through vibrato table
vibtab_pos += vibtab_add;
if (vibtab_pos/FIXEDPT_LFO>=VIBTAB_SIZE) vibtab_pos-=VIBTAB_SIZE*FIXEDPT_LFO;
vib_lut[i] = vib_table[vibtab_pos/FIXEDPT_LFO]>>vib_tshift; // 14cents (14/100 of a semitone) or 7cents
// cycle through tremolo table
tremtab_pos += tremtab_add;
if (tremtab_pos/FIXEDPT_LFO>=TREMTAB_SIZE) tremtab_pos-=TREMTAB_SIZE*FIXEDPT_LFO;
if (adlibreg[ARC_PERC_MODE]&0x80) trem_lut[i] = trem_table[tremtab_pos/FIXEDPT_LFO];
else trem_lut[i] = trem_table[TREMTAB_SIZE+tremtab_pos/FIXEDPT_LFO];
}
if (adlibreg[ARC_PERC_MODE]&0x20) {
//BassDrum
cptr = &op[6];
if (adlibreg[ARC_FEEDBACK+6]&1) {
// additive synthesis
if (cptr[9].op_state != OF_TYPE_OFF) {
if (cptr[9].vibrato) {
vibval1 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval1[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval1 = vibval_const;
if (cptr[9].tremolo) tremval1 = trem_lut; // tremolo enabled, use table
else tremval1 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
operator_advance(&cptr[9],vibval1[i]);
opfuncs[cptr[9].op_state](&cptr[9]);
operator_output(&cptr[9],0,tremval1[i]);
chanval = cptr[9].cval*2;
outbufl[i] += chanval;
}
}
} else {
// frequency modulation
if ((cptr[9].op_state != OF_TYPE_OFF) || (cptr[0].op_state != OF_TYPE_OFF)) {
if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
vibval1 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval1[i] = ((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval1 = vibval_const;
if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
vibval2 = vibval_var2;
for (i=0;i<endsamples;i++)
vibval2[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval2 = vibval_const;
if (cptr[0].tremolo) tremval1 = trem_lut; // tremolo enabled, use table
else tremval1 = tremval_const;
if (cptr[9].tremolo) tremval2 = trem_lut; // tremolo enabled, use table
else tremval2 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
operator_advance(&cptr[0],vibval1[i]);
opfuncs[cptr[0].op_state](&cptr[0]);
operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
operator_advance(&cptr[9],vibval2[i]);
opfuncs[cptr[9].op_state](&cptr[9]);
operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
chanval = cptr[9].cval*2;
outbufl[i] += chanval;
}
}
}
//TomTom (j=8)
if (op[8].op_state != OF_TYPE_OFF) {
cptr = &op[8];
if (cptr[0].vibrato) {
vibval3 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval3[i] = ((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval3 = vibval_const;
if (cptr[0].tremolo) tremval3 = trem_lut; // tremolo enabled, use table
else tremval3 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
operator_advance(&cptr[0],vibval3[i]);
opfuncs[cptr[0].op_state](&cptr[0]); //TomTom
operator_output(&cptr[0],0,tremval3[i]);
chanval = cptr[0].cval*2;
outbufl[i] += chanval;
}
}
//Snare/Hihat (j=7), Cymbal (j=8)
if ((op[7].op_state != OF_TYPE_OFF) || (op[16].op_state != OF_TYPE_OFF) ||
(op[17].op_state != OF_TYPE_OFF)) {
cptr = &op[7];
if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
vibval1 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval1[i] = ((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval1 = vibval_const;
if ((cptr[9].vibrato) && (cptr[9].op_state == OF_TYPE_OFF)) {
vibval2 = vibval_var2;
for (i=0;i<endsamples;i++)
vibval2[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval2 = vibval_const;
if (cptr[0].tremolo) tremval1 = trem_lut; // tremolo enabled, use table
else tremval1 = tremval_const;
if (cptr[9].tremolo) tremval2 = trem_lut; // tremolo enabled, use table
else tremval2 = tremval_const;
cptr = &op[8];
if ((cptr[9].vibrato) && (cptr[9].op_state == OF_TYPE_OFF)) {
vibval4 = vibval_var2;
for (i=0;i<endsamples;i++)
vibval4[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval4 = vibval_const;
if (cptr[9].tremolo) tremval4 = trem_lut; // tremolo enabled, use table
else tremval4 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
operator_advance_drums(&op[7],vibval1[i],&op[7+9],vibval2[i],&op[8+9],vibval4[i]);
opfuncs[op[7].op_state](&op[7]); //Hihat
operator_output(&op[7],0,tremval1[i]);
opfuncs[op[7+9].op_state](&op[7+9]); //Snare
operator_output(&op[7+9],0,tremval2[i]);
opfuncs[op[8+9].op_state](&op[8+9]); //Cymbal
operator_output(&op[8+9],0,tremval4[i]);
chanval = (op[7].cval + op[7+9].cval + op[8+9].cval)*2;
outbufl[i] += chanval;
}
}
}
Bitu max_channel = NUM_CHANNELS;
Bits cur_ch;
for (cur_ch=max_channel-1; cur_ch>=0; cur_ch--) {
// skip drum/percussion operators
if ((adlibreg[ARC_PERC_MODE]&0x20) && (cur_ch >= 6) && (cur_ch < 9)) goto cur_ch_cont;
Bitu k = cur_ch;
cptr = &op[cur_ch];
// check for FM/AM
if (adlibreg[ARC_FEEDBACK+k]&1) {
// 2op additive synthesis
if ((cptr[9].op_state == OF_TYPE_OFF) && (cptr[0].op_state == OF_TYPE_OFF)) goto cur_ch_cont;
if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
vibval1 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval1[i] = ((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval1 = vibval_const;
if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
vibval2 = vibval_var2;
for (i=0;i<endsamples;i++)
vibval2[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval2 = vibval_const;
if (cptr[0].tremolo) tremval1 = trem_lut; // tremolo enabled, use table
else tremval1 = tremval_const;
if (cptr[9].tremolo) tremval2 = trem_lut; // tremolo enabled, use table
else tremval2 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
// carrier1
operator_advance(&cptr[0],vibval1[i]);
opfuncs[cptr[0].op_state](&cptr[0]);
operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
// carrier2
operator_advance(&cptr[9],vibval2[i]);
opfuncs[cptr[9].op_state](&cptr[9]);
operator_output(&cptr[9],0,tremval2[i]);
chanval = cptr[9].cval + cptr[0].cval;
outbufl[i] += chanval;
}
} else {
// 2op frequency modulation
if ((cptr[9].op_state == OF_TYPE_OFF) && (cptr[0].op_state == OF_TYPE_OFF)) goto cur_ch_cont;
if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
vibval1 = vibval_var1;
for (i=0;i<endsamples;i++)
vibval1[i] = ((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval1 = vibval_const;
if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
vibval2 = vibval_var2;
for (i=0;i<endsamples;i++)
vibval2[i] = ((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
} else vibval2 = vibval_const;
if (cptr[0].tremolo) tremval1 = trem_lut; // tremolo enabled, use table
else tremval1 = tremval_const;
if (cptr[9].tremolo) tremval2 = trem_lut; // tremolo enabled, use table
else tremval2 = tremval_const;
// calculate channel output
for (i=0;i<endsamples;i++) {
// modulator
operator_advance(&cptr[0],vibval1[i]);
opfuncs[cptr[0].op_state](&cptr[0]);
operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
// carrier
operator_advance(&cptr[9],vibval2[i]);
opfuncs[cptr[9].op_state](&cptr[9]);
operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
chanval = cptr[9].cval;
outbufl[i] += chanval;
}
}
cur_ch_cont:
}
// convert to 16bit samples
if (is_stereo_output) {
for (i = 0; i < endsamples; i++) {
clipit16(outbufl[i], sndptr);
sndptr +=2;
clipit16(outbufl[i], sndptr);
sndptr +=2;
}
} else {
for (i = 0; i < endsamples; i++) {
clipit16(outbufl[i], sndptr);
sndptr +=2;
}
}
}
}