/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*
*/
#include "ultima/nuvie/sound/adplug/opl_class.h"
#include "common/scummsys.h"
namespace Ultima {
namespace Nuvie {
#ifdef _MSC_VER
# define INLINE __inline
#elif defined(__GNUC__)
# define INLINE inline
#else
# define INLINE
#endif
/* output final shift */
#if (OPL_SAMPLE_BITS==16)
#define FINAL_SH (0)
#define MAXOUT (+32767)
#define MINOUT (-32768)
#else
#define FINAL_SH (8)
#define MAXOUT (+127)
#define MINOUT (-128)
#endif
#define FREQ_SH 16 /* 16.16 fixed point (frequency calculations) */
#define EG_SH 16 /* 16.16 fixed point (EG timing) */
#define LFO_SH 24 /* 8.24 fixed point (LFO calculations) */
#define TIMER_SH 16 /* 16.16 fixed point (timers calculations) */
#define FREQ_MASK ((1<>4)
/* LFO Amplitude Modulation table (verified on real YM3812)
27 output levels (triangle waveform); 1 level takes one of: 192, 256 or 448 samples
Length: 210 elements.
Each of the elements has to be repeated
exactly 64 times (on 64 consecutive samples).
The whole table takes: 64 * 210 = 13440 samples.
When AM = 1 data is used directly
When AM = 0 data is divided by 4 before being used (losing precision is important)
*/
#define LFO_AM_TAB_ELEMENTS 210
static const uint8 lfo_am_table[LFO_AM_TAB_ELEMENTS] = {
0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1,
2, 2, 2, 2,
3, 3, 3, 3,
4, 4, 4, 4,
5, 5, 5, 5,
6, 6, 6, 6,
7, 7, 7, 7,
8, 8, 8, 8,
9, 9, 9, 9,
10, 10, 10, 10,
11, 11, 11, 11,
12, 12, 12, 12,
13, 13, 13, 13,
14, 14, 14, 14,
15, 15, 15, 15,
16, 16, 16, 16,
17, 17, 17, 17,
18, 18, 18, 18,
19, 19, 19, 19,
20, 20, 20, 20,
21, 21, 21, 21,
22, 22, 22, 22,
23, 23, 23, 23,
24, 24, 24, 24,
25, 25, 25, 25,
26, 26, 26,
25, 25, 25, 25,
24, 24, 24, 24,
23, 23, 23, 23,
22, 22, 22, 22,
21, 21, 21, 21,
20, 20, 20, 20,
19, 19, 19, 19,
18, 18, 18, 18,
17, 17, 17, 17,
16, 16, 16, 16,
15, 15, 15, 15,
14, 14, 14, 14,
13, 13, 13, 13,
12, 12, 12, 12,
11, 11, 11, 11,
10, 10, 10, 10,
9, 9, 9, 9,
8, 8, 8, 8,
7, 7, 7, 7,
6, 6, 6, 6,
5, 5, 5, 5,
4, 4, 4, 4,
3, 3, 3, 3,
2, 2, 2, 2,
1, 1, 1, 1
};
/* LFO Phase Modulation table (verified on real YM3812) */
static const int8 lfo_pm_table[8 * 8 * 2] = {
/* FNUM2/FNUM = 00 0xxxxxxx (0x0000) */
0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 0*/
0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 00 1xxxxxxx (0x0080) */
0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 0*/
1, 0, 0, 0, -1, 0, 0, 0, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 01 0xxxxxxx (0x0100) */
1, 0, 0, 0, -1, 0, 0, 0, /*LFO PM depth = 0*/
2, 1, 0, -1, -2, -1, 0, 1, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 01 1xxxxxxx (0x0180) */
1, 0, 0, 0, -1, 0, 0, 0, /*LFO PM depth = 0*/
3, 1, 0, -1, -3, -1, 0, 1, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 10 0xxxxxxx (0x0200) */
2, 1, 0, -1, -2, -1, 0, 1, /*LFO PM depth = 0*/
4, 2, 0, -2, -4, -2, 0, 2, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 10 1xxxxxxx (0x0280) */
2, 1, 0, -1, -2, -1, 0, 1, /*LFO PM depth = 0*/
5, 2, 0, -2, -5, -2, 0, 2, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 11 0xxxxxxx (0x0300) */
3, 1, 0, -1, -3, -1, 0, 1, /*LFO PM depth = 0*/
6, 3, 0, -3, -6, -3, 0, 3, /*LFO PM depth = 1*/
/* FNUM2/FNUM = 11 1xxxxxxx (0x0380) */
3, 1, 0, -1, -3, -1, 0, 1, /*LFO PM depth = 0*/
7, 3, 0, -3, -7, -3, 0, 3 /*LFO PM depth = 1*/
};
OplClass::OplClass(int rate, bool bit16, bool usestereo)
: use16bit(bit16), stereo(usestereo), oplRate(rate) {
YM3812NumChips = 0;
num_lock = 0;
cur_chip = nullptr;
YM3812Init(1, 3579545, rate);
}
void OplClass::update(short *buf, int samples) {
int i;
if (use16bit) {
YM3812UpdateOne(0, buf, samples);
if (stereo)
for (i = samples - 1; i >= 0; i--) {
buf[i * 2] = buf[i];
buf[i * 2 + 1] = buf[i];
}
} else {
short *tempbuf = new short[stereo ? samples * 2 : samples];
YM3812UpdateOne(0, tempbuf, samples);
if (stereo)
for (i = samples - 1; i >= 0; i--) {
tempbuf[i * 2] = tempbuf[i];
tempbuf[i * 2 + 1] = tempbuf[i];
}
for (i = 0; i < (stereo ? samples * 2 : samples); i++)
((char *)buf)[i] = (tempbuf[i] >> 8) ^ 0x80;
delete [] tempbuf;
}
}
void OplClass::write(int reg, int val) {
YM3812Write(0, 0, reg);
YM3812Write(0, 1, val);
}
void OplClass::init() {
YM3812ResetChip(0);
}
INLINE int limit(int val, int max, int min) {
if (val > max)
val = max;
else if (val < min)
val = min;
return val;
}
/* status set and IRQ handling */
INLINE void OPL_STATUS_SET(FM_OPL *OPL, int flag) {
/* set status flag */
OPL->status |= flag;
if (!(OPL->status & 0x80)) {
if (OPL->status & OPL->statusmask) {
/* IRQ on */
OPL->status |= 0x80;
/* callback user interrupt handler (IRQ is OFF to ON) */
if (OPL->IRQHandler)(OPL->IRQHandler)(OPL->IRQParam, 1);
}
}
}
/* status reset and IRQ handling */
INLINE void OPL_STATUS_RESET(FM_OPL *OPL, int flag) {
/* reset status flag */
OPL->status &= ~flag;
if ((OPL->status & 0x80)) {
if (!(OPL->status & OPL->statusmask)) {
OPL->status &= 0x7f;
/* callback user interrupt handler (IRQ is ON to OFF) */
if (OPL->IRQHandler)(OPL->IRQHandler)(OPL->IRQParam, 0);
}
}
}
/* IRQ mask set */
INLINE void OPL_STATUSMASK_SET(FM_OPL *OPL, int flag) {
OPL->statusmask = flag;
/* IRQ handling check */
OPL_STATUS_SET(OPL, 0);
OPL_STATUS_RESET(OPL, 0);
}
/* advance LFO to next sample */
INLINE void OplClass::advance_lfo(FM_OPL *OPL) {
uint8 tmp;
/* LFO */
OPL->lfo_am_cnt += OPL->lfo_am_inc;
if (OPL->lfo_am_cnt >= (uint32)(LFO_AM_TAB_ELEMENTS << LFO_SH)) /* lfo_am_table is 210 elements long */
OPL->lfo_am_cnt -= (uint32)(LFO_AM_TAB_ELEMENTS << LFO_SH);
tmp = lfo_am_table[ OPL->lfo_am_cnt >> LFO_SH ];
if (OPL->lfo_am_depth)
LFO_AM = tmp;
else
LFO_AM = tmp >> 2;
OPL->lfo_pm_cnt += OPL->lfo_pm_inc;
LFO_PM = ((OPL->lfo_pm_cnt >> LFO_SH) & 7) | OPL->lfo_pm_depth_range;
}
/* advance to next sample */
INLINE void OplClass::advancex(FM_OPL *OPL) {
OPL_CH *CH;
OPL_SLOT *op;
int i;
OPL->eg_timer += OPL->eg_timer_add;
while (OPL->eg_timer >= OPL->eg_timer_overflow) {
OPL->eg_timer -= OPL->eg_timer_overflow;
OPL->eg_cnt++;
for (i = 0; i < 9 * 2; i++) {
CH = &OPL->P_CH[i / 2];
op = &CH->SLOT[i & 1];
/* Envelope Generator */
switch (op->state) {
case EG_ATT: { /* attack phase */
if (!(OPL->eg_cnt & ((1 << op->eg_sh_ar) - 1))) {
op->volume += (~op->volume *
(eg_inc[op->eg_sel_ar + ((OPL->eg_cnt >> op->eg_sh_ar) & 7)])
) >> 3;
if (op->volume <= MIN_ATT_INDEX) {
op->volume = MIN_ATT_INDEX;
op->state = EG_DEC;
}
}
}
break;
case EG_DEC: /* decay phase */
if (!(OPL->eg_cnt & ((1 << op->eg_sh_dr) - 1))) {
op->volume += eg_inc[op->eg_sel_dr + ((OPL->eg_cnt >> op->eg_sh_dr) & 7)];
if (op->volume >= (int32)op->sl)
op->state = EG_SUS;
}
break;
case EG_SUS: /* sustain phase */
/* this is important behaviour:
one can change percusive/non-percussive modes on the fly and
the chip will remain in sustain phase - verified on real YM3812 */
if (op->eg_type) { /* non-percussive mode */
/* do nothing */
} else { /* percussive mode */
/* during sustain phase chip adds Release Rate (in percussive mode) */
if (!(OPL->eg_cnt & ((1 << op->eg_sh_rr) - 1))) {
op->volume += eg_inc[op->eg_sel_rr + ((OPL->eg_cnt >> op->eg_sh_rr) & 7)];
if (op->volume >= MAX_ATT_INDEX)
op->volume = MAX_ATT_INDEX;
}
/* else do nothing in sustain phase */
}
break;
case EG_REL: /* release phase */
if (!(OPL->eg_cnt & ((1 << op->eg_sh_rr) - 1))) {
op->volume += eg_inc[op->eg_sel_rr + ((OPL->eg_cnt >> op->eg_sh_rr) & 7)];
if (op->volume >= MAX_ATT_INDEX) {
op->volume = MAX_ATT_INDEX;
op->state = EG_OFF;
}
}
break;
default:
break;
}
}
}
for (i = 0; i < 9 * 2; i++) {
CH = &OPL->P_CH[i / 2];
op = &CH->SLOT[i & 1];
/* Phase Generator */
if (op->vib) {
uint8 block;
unsigned int block_fnum = CH->block_fnum;
unsigned int fnum_lfo = (block_fnum & 0x0380) >> 7;
signed int lfo_fn_table_index_offset = lfo_pm_table[LFO_PM + 16 * fnum_lfo ];
if (lfo_fn_table_index_offset) { /* LFO phase modulation active */
block_fnum += lfo_fn_table_index_offset;
block = (block_fnum & 0x1c00) >> 10;
op->Cnt += (OPL->fn_tab[block_fnum & 0x03ff] >> (7 - block)) * op->mul; //ok
} else { /* LFO phase modulation = zero */
op->Cnt += op->Incr;
}
} else { /* LFO phase modulation disabled for this operator */
op->Cnt += op->Incr;
}
}
/* The Noise Generator of the YM3812 is 23-bit shift register.
* Period is equal to 2^23-2 samples.
* Register works at sampling frequency of the chip, so output
* can change on every sample.
*
* Output of the register and input to the bit 22 is:
* bit0 XOR bit14 XOR bit15 XOR bit22
*
* Simply use bit 22 as the noise output.
*/
OPL->noise_p += OPL->noise_f;
i = OPL->noise_p >> FREQ_SH; /* number of events (shifts of the shift register) */
OPL->noise_p &= FREQ_MASK;
while (i) {
/*
uint32 j;
j = ( (OPL->noise_rng) ^ (OPL->noise_rng>>14) ^ (OPL->noise_rng>>15) ^ (OPL->noise_rng>>22) ) & 1;
OPL->noise_rng = (j<<22) | (OPL->noise_rng>>1);
*/
/*
Instead of doing all the logic operations above, we
use a trick here (and use bit 0 as the noise output).
The difference is only that the noise bit changes one
step ahead. This doesn't matter since we don't know
what is real state of the noise_rng after the reset.
*/
if (OPL->noise_rng & 1) OPL->noise_rng ^= 0x800302;
OPL->noise_rng >>= 1;
i--;
}
}
INLINE signed int OplClass::op_calc(uint32 phase, unsigned int env, signed int pm, unsigned int wave_tab) {
uint32 p;
p = (env << 4) + sin_tab[wave_tab + ((((signed int)((phase & ~FREQ_MASK) + (pm << 16))) >> FREQ_SH) & SIN_MASK) ];
if (p >= TL_TAB_LEN)
return 0;
return tl_tab[p];
}
INLINE signed int OplClass::op_calc1(uint32 phase, unsigned int env, signed int pm, unsigned int wave_tab) {
uint32 p;
int32 i;
i = (phase & ~FREQ_MASK) + pm;
/*logerror("i=%08x (i>>16)&511=%8i phase=%i [pm=%08x] ",i, (i>>16)&511, phase>>FREQ_SH, pm);*/
p = (env << 4) + sin_tab[ wave_tab + ((i >> FREQ_SH) & SIN_MASK)];
/*logerror("(p&255=%i p>>8=%i) out= %i\n", p&255,p>>8, tl_tab[p&255]>>(p>>8) );*/
if (p >= TL_TAB_LEN)
return 0;
return tl_tab[p];
}
#define volume_calc(OP) ((OP)->TLL + ((uint32)(OP)->volume) + (LFO_AM & (OP)->AMmask))
/* calculate output */
INLINE void OplClass::OPL_CALC_CH(OPL_CH *CH) {
OPL_SLOT *SLOT;
unsigned int env;
signed int out;
phase_modulation = 0;
/* SLOT 1 */
SLOT = &CH->SLOT[SLOT1];
env = volume_calc(SLOT);
out = SLOT->op1_out[0] + SLOT->op1_out[1];
SLOT->op1_out[0] = SLOT->op1_out[1];
*SLOT->connect1 += SLOT->op1_out[0];
SLOT->op1_out[1] = 0;
if (env < ENV_QUIET) {
if (!SLOT->FB)
out = 0;
SLOT->op1_out[1] = op_calc1(SLOT->Cnt, env, (out << SLOT->FB), SLOT->wavetable);
}
/* SLOT 2 */
SLOT++;
env = volume_calc(SLOT);
if (env < ENV_QUIET)
output[0] += op_calc(SLOT->Cnt, env, phase_modulation, SLOT->wavetable);
}
/*
operators used in the rhythm sounds generation process:
Envelope Generator:
channel operator register number Bass High Snare Tom Top
/ slot number TL ARDR SLRR Wave Drum Hat Drum Tom Cymbal
6 / 0 12 50 70 90 f0 +
6 / 1 15 53 73 93 f3 +
7 / 0 13 51 71 91 f1 +
7 / 1 16 54 74 94 f4 +
8 / 0 14 52 72 92 f2 +
8 / 1 17 55 75 95 f5 +
Phase Generator:
channel operator register number Bass High Snare Tom Top
/ slot number MULTIPLE Drum Hat Drum Tom Cymbal
6 / 0 12 30 +
6 / 1 15 33 +
7 / 0 13 31 + + +
7 / 1 16 34 ----- n o t u s e d -----
8 / 0 14 32 +
8 / 1 17 35 + +
channel operator register number Bass High Snare Tom Top
number number BLK/FNUM2 FNUM Drum Hat Drum Tom Cymbal
6 12,15 B6 A6 +
7 13,16 B7 A7 + + +
8 14,17 B8 A8 + + +
*/
/* calculate rhythm */
INLINE void OplClass::OPL_CALC_RH(OPL_CH *CH, unsigned int noise) {
OPL_SLOT *SLOT;
signed int out;
unsigned int env;
/* Bass Drum (verified on real YM3812):
- depends on the channel 6 'connect' register:
when connect = 0 it works the same as in normal (non-rhythm) mode (op1->op2->out)
when connect = 1 _only_ operator 2 is present on output (op2->out), operator 1 is ignored
- output sample always is multiplied by 2
*/
phase_modulation = 0;
/* SLOT 1 */
SLOT = &CH[6].SLOT[SLOT1];
env = volume_calc(SLOT);
out = SLOT->op1_out[0] + SLOT->op1_out[1];
SLOT->op1_out[0] = SLOT->op1_out[1];
if (!SLOT->CON)
phase_modulation = SLOT->op1_out[0];
//else ignore output of operator 1
SLOT->op1_out[1] = 0;
if (env < ENV_QUIET) {
if (!SLOT->FB)
out = 0;
SLOT->op1_out[1] = op_calc1(SLOT->Cnt, env, (out << SLOT->FB), SLOT->wavetable);
}
/* SLOT 2 */
SLOT++;
env = volume_calc(SLOT);
if (env < ENV_QUIET)
output[0] += op_calc(SLOT->Cnt, env, phase_modulation, SLOT->wavetable) * 2;
/* Phase generation is based on: */
// HH (13) channel 7->slot 1 combined with channel 8->slot 2 (same combination as TOP CYMBAL but different output phases)
// SD (16) channel 7->slot 1
// TOM (14) channel 8->slot 1
// TOP (17) channel 7->slot 1 combined with channel 8->slot 2 (same combination as HIGH HAT but different output phases)
/* Envelope generation based on: */
// HH channel 7->slot1
// SD channel 7->slot2
// TOM channel 8->slot1
// TOP channel 8->slot2
/* The following formulas can be well optimized.
I leave them in direct form for now (in case I've missed something).
*/
/* High Hat (verified on real YM3812) */
env = volume_calc(SLOT7_1);
if (env < ENV_QUIET) {
/* high hat phase generation:
phase = d0 or 234 (based on frequency only)
phase = 34 or 2d0 (based on noise)
*/
/* base frequency derived from operator 1 in channel 7 */
unsigned char bit7 = ((SLOT7_1->Cnt >> FREQ_SH) >> 7) & 1;
unsigned char bit3 = ((SLOT7_1->Cnt >> FREQ_SH) >> 3) & 1;
unsigned char bit2 = ((SLOT7_1->Cnt >> FREQ_SH) >> 2) & 1;
unsigned char res1 = (bit2 ^ bit7) | bit3;
/* when res1 = 0 phase = 0x000 | 0xd0; */
/* when res1 = 1 phase = 0x200 | (0xd0>>2); */
uint32 phase = res1 ? (0x200 | (0xd0 >> 2)) : 0xd0;
/* enable gate based on frequency of operator 2 in channel 8 */
unsigned char bit5e = ((SLOT8_2->Cnt >> FREQ_SH) >> 5) & 1;
unsigned char bit3e = ((SLOT8_2->Cnt >> FREQ_SH) >> 3) & 1;
unsigned char res2 = (bit3e ^ bit5e);
/* when res2 = 0 pass the phase from calculation above (res1); */
/* when res2 = 1 phase = 0x200 | (0xd0>>2); */
if (res2)
phase = (0x200 | (0xd0 >> 2));
/* when phase & 0x200 is set and noise=1 then phase = 0x200|0xd0 */
/* when phase & 0x200 is set and noise=0 then phase = 0x200|(0xd0>>2), ie no change */
if (phase & 0x200) {
if (noise)
phase = 0x200 | 0xd0;
} else
/* when phase & 0x200 is clear and noise=1 then phase = 0xd0>>2 */
/* when phase & 0x200 is clear and noise=0 then phase = 0xd0, ie no change */
{
if (noise)
phase = 0xd0 >> 2;
}
output[0] += op_calc(phase << FREQ_SH, env, 0, SLOT7_1->wavetable) * 2;
}
/* Snare Drum (verified on real YM3812) */
env = volume_calc(SLOT7_2);
if (env < ENV_QUIET) {
/* base frequency derived from operator 1 in channel 7 */
unsigned char bit8 = ((SLOT7_1->Cnt >> FREQ_SH) >> 8) & 1;
/* when bit8 = 0 phase = 0x100; */
/* when bit8 = 1 phase = 0x200; */
uint32 phase = bit8 ? 0x200 : 0x100;
/* Noise bit XOR'es phase by 0x100 */
/* when noisebit = 0 pass the phase from calculation above */
/* when noisebit = 1 phase ^= 0x100; */
/* in other words: phase ^= (noisebit<<8); */
if (noise)
phase ^= 0x100;
output[0] += op_calc(phase << FREQ_SH, env, 0, SLOT7_1->wavetable) * 2;
}
/* Tom Tom (verified on real YM3812) */
env = volume_calc(SLOT8_1);
if (env < ENV_QUIET)
output[0] += op_calc(SLOT8_1->Cnt, env, 0, SLOT8_1->wavetable) * 2;
/* Top Cymbal (verified on real YM3812) */
env = volume_calc(SLOT8_2);
if (env < ENV_QUIET) {
/* base frequency derived from operator 1 in channel 7 */
unsigned char bit7 = ((SLOT7_1->Cnt >> FREQ_SH) >> 7) & 1;
unsigned char bit3 = ((SLOT7_1->Cnt >> FREQ_SH) >> 3) & 1;
unsigned char bit2 = ((SLOT7_1->Cnt >> FREQ_SH) >> 2) & 1;
unsigned char res1 = (bit2 ^ bit7) | bit3;
/* when res1 = 0 phase = 0x000 | 0x100; */
/* when res1 = 1 phase = 0x200 | 0x100; */
uint32 phase = res1 ? 0x300 : 0x100;
/* enable gate based on frequency of operator 2 in channel 8 */
unsigned char bit5e = ((SLOT8_2->Cnt >> FREQ_SH) >> 5) & 1;
unsigned char bit3e = ((SLOT8_2->Cnt >> FREQ_SH) >> 3) & 1;
unsigned char res2 = (bit3e ^ bit5e);
/* when res2 = 0 pass the phase from calculation above (res1); */
/* when res2 = 1 phase = 0x200 | 0x100; */
if (res2)
phase = 0x300;
output[0] += op_calc(phase << FREQ_SH, env, 0, SLOT8_2->wavetable) * 2;
}
}
/* generic table initialize */
int OplClass::init_tables(void) {
signed int i, x;
signed int n;
double o, m;
for (x = 0; x < TL_RES_LEN; x++) {
m = (1 << 16) / pow(2, (x + 1) * (ENV_STEP / 4.0) / 8.0);
m = floor(m);
/* we never reach (1<<16) here due to the (x+1) */
/* result fits within 16 bits at maximum */
n = (int)m; /* 16 bits here */
n >>= 4; /* 12 bits here */
if (n & 1) /* round to nearest */
n = (n >> 1) + 1;
else
n = n >> 1;
/* 11 bits here (rounded) */
n <<= 1; /* 12 bits here (as in real chip) */
tl_tab[ x * 2 + 0 ] = n;
tl_tab[ x * 2 + 1 ] = -tl_tab[ x * 2 + 0 ];
for (i = 1; i < 12; i++) {
tl_tab[ x * 2 + 0 + i * 2 * TL_RES_LEN ] = tl_tab[ x * 2 + 0 ] >> i;
tl_tab[ x * 2 + 1 + i * 2 * TL_RES_LEN ] = -tl_tab[ x * 2 + 0 + i * 2 * TL_RES_LEN ];
}
}
/*logerror("FMOPL.C: TL_TAB_LEN = %i elements (%i bytes)\n",TL_TAB_LEN, (int)sizeof(tl_tab));*/
for (i = 0; i < SIN_LEN; i++) {
/* non-standard sinus */
m = sin(((i * 2) + 1) * M_PI / SIN_LEN); /* checked against the real chip */
/* we never reach zero here due to ((i*2)+1) */
if (m > 0.0)
o = 8 * log(1.0 / m) / log(2); /* convert to 'decibels' */
else
o = 8 * log(-1.0 / m) / log(2); /* convert to 'decibels' */
o = o / (ENV_STEP / 4);
n = (int)(2.0 * o);
if (n & 1) /* round to nearest */
n = (n >> 1) + 1;
else
n = n >> 1;
sin_tab[ i ] = n * 2 + (m >= 0.0 ? 0 : 1);
/*logerror("FMOPL.C: sin [%4i (hex=%03x)]= %4i (tl_tab value=%5i)\n", i, i, sin_tab[i], tl_tab[sin_tab[i]] );*/
}
for (i = 0; i < SIN_LEN; i++) {
/* waveform 1: __ __ */
/* / \____/ \____*/
/* output only first half of the sinus waveform (positive one) */
if (i & (1 << (SIN_BITS - 1)))
sin_tab[1 * SIN_LEN + i] = TL_TAB_LEN;
else
sin_tab[1 * SIN_LEN + i] = sin_tab[i];
/* waveform 2: __ __ __ __ */
/* / \/ \/ \/ \*/
/* abs(sin) */
sin_tab[2 * SIN_LEN + i] = sin_tab[i & (SIN_MASK >> 1) ];
/* waveform 3: _ _ _ _ */
/* / |_/ |_/ |_/ |_*/
/* abs(output only first quarter of the sinus waveform) */
if (i & (1 << (SIN_BITS - 2)))
sin_tab[3 * SIN_LEN + i] = TL_TAB_LEN;
else
sin_tab[3 * SIN_LEN + i] = sin_tab[i & (SIN_MASK >> 2)];
/*logerror("FMOPL.C: sin1[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[1*SIN_LEN+i], tl_tab[sin_tab[1*SIN_LEN+i]] );
logerror("FMOPL.C: sin2[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[2*SIN_LEN+i], tl_tab[sin_tab[2*SIN_LEN+i]] );
logerror("FMOPL.C: sin3[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[3*SIN_LEN+i], tl_tab[sin_tab[3*SIN_LEN+i]] );*/
}
/*logerror("FMOPL.C: ENV_QUIET= %08x (dec*8=%i)\n", ENV_QUIET, ENV_QUIET*8 );*/
return 1;
}
static void OPLCloseTable(void) {
#ifdef SAVE_SAMPLE
fclose(sample[0]);
#endif
}
static void OPL_initalize(FM_OPL *OPL) {
int i;
/* frequency base */
OPL->freqbase = (OPL->rate) ? ((double)OPL->clock / 72.0) / OPL->rate : 0;
/* Timer base time */
OPL->TimerBase = 1.0 / ((double)OPL->clock / 72.0);
/* make fnumber -> increment counter table */
for (i = 0 ; i < 1024 ; i++) {
/* opn phase increment counter = 20bit */
OPL->fn_tab[i] = (uint32)((double)i * 64 * OPL->freqbase * (1 << (FREQ_SH - 10))); /* -10 because chip works with 10.10 fixed point, while we use 16.16 */
}
/* Amplitude modulation: 27 output levels (triangle waveform); 1 level takes one of: 192, 256 or 448 samples */
/* One entry from LFO_AM_TABLE lasts for 64 samples */
OPL->lfo_am_inc = (1.0 / 64.0) * (1 << LFO_SH) * OPL->freqbase;
/* Vibrato: 8 output levels (triangle waveform); 1 level takes 1024 samples */
OPL->lfo_pm_inc = (1.0 / 1024.0) * (1 << LFO_SH) * OPL->freqbase;
/*logerror ("OPL->lfo_am_inc = %8x ; OPL->lfo_pm_inc = %8x\n", OPL->lfo_am_inc, OPL->lfo_pm_inc);*/
/* Noise generator: a step takes 1 sample */
OPL->noise_f = (1.0 / 1.0) * (1 << FREQ_SH) * OPL->freqbase;
OPL->eg_timer_add = (1 << EG_SH) * OPL->freqbase;
OPL->eg_timer_overflow = (1) * (1 << EG_SH);
/*logerror("OPLinit eg_timer_add=%8x eg_timer_overflow=%8x\n", OPL->eg_timer_add, OPL->eg_timer_overflow);*/
}
INLINE void FM_KEYON(OPL_SLOT *SLOT, uint32 key_set) {
if (!SLOT->key) {
/* restart Phase Generator */
SLOT->Cnt = 0;
/* phase -> Attack */
SLOT->state = EG_ATT;
}
SLOT->key |= key_set;
}
INLINE void FM_KEYOFF(OPL_SLOT *SLOT, uint32 key_clr) {
if (SLOT->key) {
SLOT->key &= key_clr;
if (!SLOT->key) {
/* phase -> Release */
if (SLOT->state > EG_REL)
SLOT->state = EG_REL;
}
}
}
/* update phase increment counter of operator (also update the EG rates if necessary) */
INLINE void CALC_FCSLOT(OPL_CH *CH, OPL_SLOT *SLOT) {
int ksr;
/* (frequency) phase increment counter */
SLOT->Incr = CH->fc * SLOT->mul;
ksr = CH->kcode >> SLOT->KSR;
if (SLOT->ksr != ksr) {
SLOT->ksr = ksr;
/* calculate envelope generator rates */
if ((SLOT->ar + SLOT->ksr) < 16 + 62) {
SLOT->eg_sh_ar = eg_rate_shift [SLOT->ar + SLOT->ksr ];
SLOT->eg_sel_ar = eg_rate_select[SLOT->ar + SLOT->ksr ];
} else {
SLOT->eg_sh_ar = 0;
SLOT->eg_sel_ar = 13 * RATE_STEPS;
}
SLOT->eg_sh_dr = eg_rate_shift [SLOT->dr + SLOT->ksr ];
SLOT->eg_sel_dr = eg_rate_select[SLOT->dr + SLOT->ksr ];
SLOT->eg_sh_rr = eg_rate_shift [SLOT->rr + SLOT->ksr ];
SLOT->eg_sel_rr = eg_rate_select[SLOT->rr + SLOT->ksr ];
}
}
/* set multi,am,vib,EG-TYP,KSR,mul */
INLINE void set_mul(FM_OPL *OPL, int slot, int v) {
OPL_CH *CH = &OPL->P_CH[slot / 2];
OPL_SLOT *SLOT = &CH->SLOT[slot & 1];
SLOT->mul = mul_tab[v & 0x0f];
SLOT->KSR = (v & 0x10) ? 0 : 2;
SLOT->eg_type = (v & 0x20);
SLOT->vib = (v & 0x40);
SLOT->AMmask = (v & 0x80) ? ~0 : 0;
CALC_FCSLOT(CH, SLOT);
}
/* set ksl & tl */
INLINE void set_ksl_tl(FM_OPL *OPL, int slot, int v) {
OPL_CH *CH = &OPL->P_CH[slot / 2];
OPL_SLOT *SLOT = &CH->SLOT[slot & 1];
int ksl = v >> 6; /* 0 / 1.5 / 3.0 / 6.0 dB/OCT */
SLOT->ksl = ksl ? 3 - ksl : 31;
SLOT->TL = (v & 0x3f) << (ENV_BITS - 1 - 7); /* 7 bits TL (bit 6 = always 0) */
SLOT->TLL = SLOT->TL + (CH->ksl_base >> SLOT->ksl);
}
/* set attack rate & decay rate */
INLINE void set_ar_dr(FM_OPL *OPL, int slot, int v) {
OPL_CH *CH = &OPL->P_CH[slot / 2];
OPL_SLOT *SLOT = &CH->SLOT[slot & 1];
SLOT->ar = (v >> 4) ? 16 + ((v >> 4) << 2) : 0;
if ((SLOT->ar + SLOT->ksr) < 16 + 62) {
SLOT->eg_sh_ar = eg_rate_shift [SLOT->ar + SLOT->ksr ];
SLOT->eg_sel_ar = eg_rate_select[SLOT->ar + SLOT->ksr ];
} else {
SLOT->eg_sh_ar = 0;
SLOT->eg_sel_ar = 13 * RATE_STEPS;
}
SLOT->dr = (v & 0x0f) ? 16 + ((v & 0x0f) << 2) : 0;
SLOT->eg_sh_dr = eg_rate_shift [SLOT->dr + SLOT->ksr ];
SLOT->eg_sel_dr = eg_rate_select[SLOT->dr + SLOT->ksr ];
}
/* set sustain level & release rate */
INLINE void set_sl_rr(FM_OPL *OPL, int slot, int v) {
OPL_CH *CH = &OPL->P_CH[slot / 2];
OPL_SLOT *SLOT = &CH->SLOT[slot & 1];
SLOT->sl = sl_tab[ v >> 4 ];
SLOT->rr = (v & 0x0f) ? 16 + ((v & 0x0f) << 2) : 0;
SLOT->eg_sh_rr = eg_rate_shift [SLOT->rr + SLOT->ksr ];
SLOT->eg_sel_rr = eg_rate_select[SLOT->rr + SLOT->ksr ];
}
/* write a value v to register r on OPL chip */
void OplClass::OPLWriteReg(FM_OPL *OPL, int r, int v) {
OPL_CH *CH;
int slot;
int block_fnum;
/* adjust bus to 8 bits */
r &= 0xff;
v &= 0xff;
switch (r & 0xe0) {
case 0x00: /* 00-1f:control */
switch (r & 0x1f) {
case 0x01: /* waveform select enable */
if (OPL->type & OPL_TYPE_WAVESEL) {
OPL->wavesel = v & 0x20;
/* do not change the waveform previously selected */
}
break;
case 0x02: /* Timer 1 */
OPL->T[0] = (256 - v) * 4;
break;
case 0x03: /* Timer 2 */
OPL->T[1] = (256 - v) * 16;
break;
case 0x04: /* IRQ clear / mask and Timer enable */
if (v & 0x80) {
/* IRQ flag clear */
OPL_STATUS_RESET(OPL, 0x7f);
} else {
/* set IRQ mask ,timer enable*/
uint8 st1 = v & 1;
uint8 st2 = (v >> 1) & 1;
/* IRQRST,T1MSK,t2MSK,EOSMSK,BRMSK,x,ST2,ST1 */
OPL_STATUS_RESET(OPL, v & 0x78);
OPL_STATUSMASK_SET(OPL, ((~v) & 0x78) | 0x01);
/* timer 2 */
if (OPL->st[1] != st2) {
double interval = st2 ? (double)OPL->T[1] * OPL->TimerBase : 0.0;
OPL->st[1] = st2;
if (OPL->TimerHandler)(OPL->TimerHandler)(OPL->TimerParam + 1, interval);
}
/* timer 1 */
if (OPL->st[0] != st1) {
double interval = st1 ? (double)OPL->T[0] * OPL->TimerBase : 0.0;
OPL->st[0] = st1;
if (OPL->TimerHandler)(OPL->TimerHandler)(OPL->TimerParam + 0, interval);
}
}
break;
case 0x08: /* MODE,DELTA-T : CSM,NOTESEL,x,x,smpl,da/ad,64k,rom */
OPL->mode = v;
break;
}
break;
case 0x20: /* am ON, vib ON, ksr, eg_type, mul */
slot = slot_array[r & 0x1f];
if (slot < 0) return;
set_mul(OPL, slot, v);
break;
case 0x40:
slot = slot_array[r & 0x1f];
if (slot < 0) return;
set_ksl_tl(OPL, slot, v);
break;
case 0x60:
slot = slot_array[r & 0x1f];
if (slot < 0) return;
set_ar_dr(OPL, slot, v);
break;
case 0x80:
slot = slot_array[r & 0x1f];
if (slot < 0) return;
set_sl_rr(OPL, slot, v);
break;
case 0xa0:
if (r == 0xbd) { /* am depth, vibrato depth, r,bd,sd,tom,tc,hh */
OPL->lfo_am_depth = v & 0x80;
OPL->lfo_pm_depth_range = (v & 0x40) ? 8 : 0;
OPL->rhythm = v & 0x3f;
if (OPL->rhythm & 0x20) {
/* BD key on/off */
if (v & 0x10) {
FM_KEYON(&OPL->P_CH[6].SLOT[SLOT1], 2U);
FM_KEYON(&OPL->P_CH[6].SLOT[SLOT2], 2U);
} else {
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1], ~2U);
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2], ~2U);
}
/* HH key on/off */
if (v & 0x01) FM_KEYON(&OPL->P_CH[7].SLOT[SLOT1], 2U);
else FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1], ~2U);
/* SD key on/off */
if (v & 0x08) FM_KEYON(&OPL->P_CH[7].SLOT[SLOT2], 2U);
else FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2], ~2U);
/* TOM key on/off */
if (v & 0x04) FM_KEYON(&OPL->P_CH[8].SLOT[SLOT1], 2U);
else FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1], ~2U);
/* TOP-CY key on/off */
if (v & 0x02U) FM_KEYON(&OPL->P_CH[8].SLOT[SLOT2], 2U);
else FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2], ~2U);
} else {
/* BD key off */
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1], ~2U);
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2], ~2U);
/* HH key off */
FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1], ~2U);
/* SD key off */
FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2], ~2U);
/* TOM key off */
FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1], ~2U);
/* TOP-CY off */
FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2], ~2U);
}
return;
}
/* keyon,block,fnum */
if ((r & 0x0f) > 8) return;
CH = &OPL->P_CH[r & 0x0f];
if (!(r & 0x10)) {
/* a0-a8 */
block_fnum = (CH->block_fnum & 0x1f00) | v;
} else {
/* b0-b8 */
block_fnum = ((v & 0x1f) << 8) | (CH->block_fnum & 0xff);
if (v & 0x20) {
FM_KEYON(&CH->SLOT[SLOT1], 1U);
FM_KEYON(&CH->SLOT[SLOT2], 1U);
} else {
FM_KEYOFF(&CH->SLOT[SLOT1], ~1U);
FM_KEYOFF(&CH->SLOT[SLOT2], ~1U);
}
}
/* update */
if (CH->block_fnum != (uint32)block_fnum) {
uint8 block = block_fnum >> 10;
CH->block_fnum = block_fnum;
CH->ksl_base = ksl_tab[block_fnum >> 6];
CH->fc = OPL->fn_tab[block_fnum & 0x03ff] >> (7 - block);
/* BLK 2,1,0 bits -> bits 3,2,1 of kcode */
CH->kcode = (CH->block_fnum & 0x1c00) >> 9;
/* the info below is actually opposite to what is stated in the Manuals (verifed on real YM3812) */
/* if notesel == 0 -> lsb of kcode is bit 10 (MSB) of fnum */
/* if notesel == 1 -> lsb of kcode is bit 9 (MSB-1) of fnum */
if (OPL->mode & 0x40)
CH->kcode |= (CH->block_fnum & 0x100) >> 8; /* notesel == 1 */
else
CH->kcode |= (CH->block_fnum & 0x200) >> 9; /* notesel == 0 */
/* refresh Total Level in both SLOTs of this channel */
CH->SLOT[SLOT1].TLL = CH->SLOT[SLOT1].TL + (CH->ksl_base >> CH->SLOT[SLOT1].ksl);
CH->SLOT[SLOT2].TLL = CH->SLOT[SLOT2].TL + (CH->ksl_base >> CH->SLOT[SLOT2].ksl);
/* refresh frequency counter in both SLOTs of this channel */
CALC_FCSLOT(CH, &CH->SLOT[SLOT1]);
CALC_FCSLOT(CH, &CH->SLOT[SLOT2]);
}
break;
case 0xc0:
/* FB,C */
if ((r & 0x0f) > 8) return;
CH = &OPL->P_CH[r & 0x0f];
CH->SLOT[SLOT1].FB = (v >> 1) & 7 ? ((v >> 1) & 7) + 7 : 0;
CH->SLOT[SLOT1].CON = v & 1;
CH->SLOT[SLOT1].connect1 = CH->SLOT[SLOT1].CON ? &output[0] : &phase_modulation;
break;
case 0xe0: /* waveform select */
/* simply ignore write to the waveform select register if selecting not enabled in test register */
if (OPL->wavesel) {
slot = slot_array[r & 0x1f];
if (slot < 0) return;
CH = &OPL->P_CH[slot / 2];
CH->SLOT[slot & 1].wavetable = (v & 0x03) * SIN_LEN;
}
break;
}
}
/* lock/unlock for common table */
int OplClass::OPL_LockTable(void) {
num_lock++;
if (num_lock > 1) return 0;
/* first time */
cur_chip = nullptr;
/* allocate total level table (128kb space) */
if (!init_tables()) {
num_lock--;
return -1;
}
return 0;
}
void OplClass::OPL_UnLockTable(void) {
if (num_lock) num_lock--;
if (num_lock) return;
/* last time */
cur_chip = nullptr;
OPLCloseTable();
}
void OplClass::OPLResetChip(FM_OPL *OPL) {
int c, s;
int i;
OPL->eg_timer = 0;
OPL->eg_cnt = 0;
OPL->noise_rng = 1; /* noise shift register */
OPL->mode = 0; /* normal mode */
OPL_STATUS_RESET(OPL, 0x7f);
/* reset with register write */
OPLWriteReg(OPL, 0x01, 0); /* wavesel disable */
OPLWriteReg(OPL, 0x02, 0); /* Timer1 */
OPLWriteReg(OPL, 0x03, 0); /* Timer2 */
OPLWriteReg(OPL, 0x04, 0); /* IRQ mask clear */
for (i = 0xff ; i >= 0x20 ; i--) OPLWriteReg(OPL, i, 0);
/* reset operator parameters */
for (c = 0 ; c < 9 ; c++) {
OPL_CH *CH = &OPL->P_CH[c];
for (s = 0 ; s < 2 ; s++) {
/* wave table */
CH->SLOT[s].wavetable = 0;
CH->SLOT[s].state = EG_OFF;
CH->SLOT[s].volume = MAX_ATT_INDEX;
}
}
}
/* Create one of virtual YM3812 */
/* 'clock' is chip clock in Hz */
/* 'rate' is sampling rate */
FM_OPL *OplClass::OPLCreate(int type, int clock, int rate) {
char *ptr;
FM_OPL *OPL;
int state_size;
if (OPL_LockTable() == -1) return nullptr;
/* calculate OPL state size */
state_size = sizeof(FM_OPL);
/* allocate memory block */
ptr = (char *)malloc(state_size);
if (ptr == nullptr)
return nullptr;
/* clear */
memset(ptr, 0, state_size);
OPL = (FM_OPL *)ptr;
ptr += sizeof(FM_OPL);
OPL->type = type;
OPL->clock = clock;
OPL->rate = rate;
/* init global tables */
OPL_initalize(OPL);
/* reset chip */
OPLResetChip(OPL);
return OPL;
}
/* Destroy one of virtual YM3812 */
void OplClass::OPLDestroy(FM_OPL *OPL) {
OPL_UnLockTable();
free(OPL);
}
/* Option handlers */
static void OPLSetTimerHandler(FM_OPL *OPL, OPL_TIMERHANDLER TimerHandler, int channelOffset) {
OPL->TimerHandler = TimerHandler;
OPL->TimerParam = channelOffset;
}
static void OPLSetIRQHandler(FM_OPL *OPL, OPL_IRQHANDLER IRQHandler, int param) {
OPL->IRQHandler = IRQHandler;
OPL->IRQParam = param;
}
static void OPLSetUpdateHandler(FM_OPL *OPL, OPL_UPDATEHANDLER UpdateHandler, int param) {
OPL->UpdateHandler = UpdateHandler;
OPL->UpdateParam = param;
}
/* YM3812 I/O interface */
int OplClass::OPLWrite(FM_OPL *OPL, int a, int v) {
if (!(a & 1)) {
/* address port */
OPL->address = v & 0xff;
} else {
/* data port */
if (OPL->UpdateHandler) OPL->UpdateHandler(OPL->UpdateParam, 0);
OPLWriteReg(OPL, OPL->address, v);
}
return OPL->status >> 7;
}
static unsigned char OPLRead(FM_OPL *OPL, int a) {
if (!(a & 1)) {
/* status port */
return OPL->status & (OPL->statusmask | 0x80);
}
return 0xff;
}
/* CSM Key Control */
INLINE void CSMKeyControll(OPL_CH *CH) {
FM_KEYON(&CH->SLOT[SLOT1], 4U);
FM_KEYON(&CH->SLOT[SLOT2], 4U);
/* The key off should happen exactly one sample later - not implemented correctly yet */
FM_KEYOFF(&CH->SLOT[SLOT1], ~4U);
FM_KEYOFF(&CH->SLOT[SLOT2], ~4U);
}
static int OPLTimerOver(FM_OPL *OPL, int c) {
if (c) {
/* Timer B */
OPL_STATUS_SET(OPL, 0x20);
} else {
/* Timer A */
OPL_STATUS_SET(OPL, 0x40);
/* CSM mode key,TL control */
if (OPL->mode & 0x80) {
/* CSM mode total level latch and auto key on */
int ch;
if (OPL->UpdateHandler) OPL->UpdateHandler(OPL->UpdateParam, 0);
for (ch = 0; ch < 9; ch++)
CSMKeyControll(&OPL->P_CH[ch]);
}
}
/* reload timer */
if (OPL->TimerHandler)(OPL->TimerHandler)(OPL->TimerParam + c, (double)OPL->T[c]*OPL->TimerBase);
return OPL->status >> 7;
}
#if (BUILD_YM3812)
int OplClass::YM3812Init(int num, int clock, int rate) {
int i;
if (YM3812NumChips)
return -1; /* duplicate init. */
YM3812NumChips = num;
for (i = 0; i < YM3812NumChips; i++) {
/* emulator create */
OPL_YM3812[i] = OPLCreate(OPL_TYPE_YM3812, clock, rate);
if (OPL_YM3812[i] == nullptr) {
/* it's really bad - we run out of memeory */
YM3812NumChips = 0;
return -1;
}
}
return 0;
}
void OplClass::YM3812Shutdown(void) {
int i;
for (i = 0; i < YM3812NumChips; i++) {
/* emulator shutdown */
OPLDestroy(OPL_YM3812[i]);
OPL_YM3812[i] = nullptr;
}
YM3812NumChips = 0;
}
void OplClass::YM3812ResetChip(int which) {
OPLResetChip(OPL_YM3812[which]);
}
int OplClass::YM3812Write(int which, int a, int v) {
return OPLWrite(OPL_YM3812[which], a, v);
}
unsigned char OplClass::YM3812Read(int which, int a) {
/* YM3812 always returns bit2 and bit1 in HIGH state */
return OPLRead(OPL_YM3812[which], a) | 0x06 ;
}
int OplClass::YM3812TimerOver(int which, int c) {
return OPLTimerOver(OPL_YM3812[which], c);
}
void OplClass::YM3812SetTimerHandler(int which, OPL_TIMERHANDLER TimerHandler, int channelOffset) {
OPLSetTimerHandler(OPL_YM3812[which], TimerHandler, channelOffset);
}
void OplClass::YM3812SetIRQHandler(int which, OPL_IRQHANDLER IRQHandler, int param) {
OPLSetIRQHandler(OPL_YM3812[which], IRQHandler, param);
}
void OplClass::YM3812SetUpdateHandler(int which, OPL_UPDATEHANDLER UpdateHandler, int param) {
OPLSetUpdateHandler(OPL_YM3812[which], UpdateHandler, param);
}
/*
** Generate samples for one of the YM3812's
**
** 'which' is the virtual YM3812 number
** '*buffer' is the output buffer pointer
** 'length' is the number of samples that should be generated
*/
void OplClass::YM3812UpdateOne(int which, int16 *buffer, int length) {
FM_OPL *OPL = OPL_YM3812[which];
uint8 rhythm = OPL->rhythm & 0x20;
OPLSAMPLE *buf = buffer;
int i;
if ((void *)OPL != cur_chip) {
cur_chip = (void *)OPL;
/* rhythm slots */
SLOT7_1 = &OPL->P_CH[7].SLOT[SLOT1];
SLOT7_2 = &OPL->P_CH[7].SLOT[SLOT2];
SLOT8_1 = &OPL->P_CH[8].SLOT[SLOT1];
SLOT8_2 = &OPL->P_CH[8].SLOT[SLOT2];
}
for (i = 0; i < length ; i++) {
int lt;
output[0] = 0;
advance_lfo(OPL);
/* FM part */
OPL_CALC_CH(&OPL->P_CH[0]);
OPL_CALC_CH(&OPL->P_CH[1]);
OPL_CALC_CH(&OPL->P_CH[2]);
OPL_CALC_CH(&OPL->P_CH[3]);
OPL_CALC_CH(&OPL->P_CH[4]);
OPL_CALC_CH(&OPL->P_CH[5]);
if (!rhythm) {
OPL_CALC_CH(&OPL->P_CH[6]);
OPL_CALC_CH(&OPL->P_CH[7]);
OPL_CALC_CH(&OPL->P_CH[8]);
} else { /* Rhythm part */
OPL_CALC_RH(&OPL->P_CH[0], (OPL->noise_rng >> 0) & 1);
}
lt = output[0];
lt >>= FINAL_SH;
/* limit check */
lt = limit(lt , MAXOUT, MINOUT);
#ifdef SAVE_SAMPLE
SAVE_ALL_CHANNELS
#endif
/* store to sound buffer */
buf[i] = lt;
advancex(OPL);
}
}
#endif /* BUILD_YM3812 */
} // End of namespace Nuvie
} // End of namespace Ultima