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zmusic/thirdparty/oplsynth/fmopl.cpp
Christoph Oelckers a4eae42ec5 - initial commit
2020-01-02 17:52:30 +01:00

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// license:GPL-2.0+
// copyright-holders:Jarek Burczynski,Tatsuyuki Satoh
/*
This file is based on fmopl.c from MAME. The non-YM3816 parts have been
ripped out in the interest of making this simpler, since Doom music doesn't
need them. I also made it render the sound a voice at a time instead of a
sample at a time, so unused voices don't waste time being calculated. If all
voices are playing, it's not much difference, but it does offer a big
improvement when only a few voices are playing.
**
** File: fmopl.c - software implementation of FM sound generator
** types OPL and OPL2
**
** Copyright Jarek Burczynski (bujar at mame dot net)
** Copyright Tatsuyuki Satoh , MultiArcadeMachineEmulator development
**
** Version 0.72
**
Revision History:
04-08-2003 Jarek Burczynski:
- removed BFRDY hack. BFRDY is busy flag, and it should be 0 only when the chip
handles memory read/write or during the adpcm synthesis when the chip
requests another byte of ADPCM data.
24-07-2003 Jarek Burczynski:
- added a small hack for Y8950 status BFRDY flag (bit 3 should be set after
some (unknown) delay). Right now it's always set.
14-06-2003 Jarek Burczynski:
- implemented all of the status register flags in Y8950 emulation
- renamed y8950_set_delta_t_memory() parameters from _rom_ to _mem_ since
they can be either RAM or ROM
08-10-2002 Jarek Burczynski (thanks to Dox for the YM3526 chip)
- corrected ym3526_read() to always set bit 2 and bit 1
to HIGH state - identical to ym3812_read (verified on real YM3526)
04-28-2002 Jarek Burczynski:
- binary exact Envelope Generator (verified on real YM3812);
compared to YM2151: the EG clock is equal to internal_clock,
rates are 2 times slower and volume resolution is one bit less
- modified interface functions (they no longer return pointer -
that's internal to the emulator now):
- new wrapper functions for OPLCreate: ym3526_init(), ym3812_init() and y8950_init()
- corrected 'off by one' error in feedback calculations (when feedback is off)
- enabled waveform usage (credit goes to Vlad Romascanu and zazzal22)
- speeded up noise generator calculations (Nicola Salmoria)
03-24-2002 Jarek Burczynski (thanks to Dox for the YM3812 chip)
Complete rewrite (all verified on real YM3812):
- corrected sin_tab and tl_tab data
- corrected operator output calculations
- corrected waveform_select_enable register;
simply: ignore all writes to waveform_select register when
waveform_select_enable == 0 and do not change the waveform previously selected.
- corrected KSR handling
- corrected Envelope Generator: attack shape, Sustain mode and
Percussive/Non-percussive modes handling
- Envelope Generator rates are two times slower now
- LFO amplitude (tremolo) and phase modulation (vibrato)
- rhythm sounds phase generation
- white noise generator (big thanks to Olivier Galibert for mentioning Berlekamp-Massey algorithm)
- corrected key on/off handling (the 'key' signal is ORed from three sources: FM, rhythm and CSM)
- funky details (like ignoring output of operator 1 in BD rhythm sound when connect == 1)
12-28-2001 Acho A. Tang
- reflected Delta-T EOS status on Y8950 status port.
- fixed subscription range of attack/decay tables
To do:
add delay before key off in CSM mode (see CSMKeyControll)
verify volume of the FM part on the Y8950
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdint.h>
#include <string>
//#include "driver.h" /* use M.A.M.E. */
#include "opl.h"
/* compiler dependence */
#ifndef OSD_CPU_H
#define OSD_CPU_H
#endif
#ifndef PI
#define PI 3.14159265358979323846
#endif
#ifdef _MSC_VER
#pragma warning (disable: 4244)
#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<<FREQ_SH)-1)
/* envelope output entries */
#define ENV_BITS 10
#define ENV_LEN (1<<ENV_BITS)
#define ENV_STEP (128.0/ENV_LEN)
#define MAX_ATT_INDEX ((1<<(ENV_BITS-1))-1) /*511*/
#define MIN_ATT_INDEX (0)
/* sinwave entries */
#define SIN_BITS 10
#define SIN_LEN (1<<SIN_BITS)
#define SIN_MASK (SIN_LEN-1)
#define TL_RES_LEN (256) /* 8 bits addressing (real chip) */
/* register number to channel number , slot offset */
#define SLOT1 0
#define SLOT2 1
/* Envelope Generator phases */
#define EG_ATT 4
#define EG_DEC 3
#define EG_SUS 2
#define EG_REL 1
#define EG_OFF 0
#define OPL_CLOCK 3579545 // master clock (Hz)
#define OPL_RATE 49716 // sampling rate (Hz)
#define OPL_TIMERBASE (OPL_CLOCK / 72.0) // Timer base time (==sampling time)
#define OPL_FREQBASE (OPL_TIMERBASE / OPL_RATE) // frequency base
/* Saving is necessary for member of the 'R' mark for suspend/resume */
struct OPL_SLOT
{
uint32_t ar; /* attack rate: AR<<2 */
uint32_t dr; /* decay rate: DR<<2 */
uint32_t rr; /* release rate:RR<<2 */
uint8_t KSR; /* key scale rate */
uint8_t ksl; /* keyscale level */
uint8_t ksr; /* key scale rate: kcode>>KSR */
uint8_t mul; /* multiple: mul_tab[ML] */
/* Phase Generator */
uint32_t Cnt; /* frequency counter */
uint32_t Incr; /* frequency counter step */
uint8_t FB; /* feedback shift value */
int32_t *connect1; /* slot1 output pointer */
int32_t op1_out[2]; /* slot1 output for feedback */
uint8_t CON; /* connection (algorithm) type */
/* Envelope Generator */
uint8_t eg_type; /* percussive/non-percussive mode */
uint8_t state; /* phase type */
uint32_t TL; /* total level: TL << 2 */
int32_t TLL; /* adjusted now TL */
int32_t volume; /* envelope counter */
uint32_t sl; /* sustain level: sl_tab[SL] */
uint8_t eg_sh_ar; /* (attack state) */
uint8_t eg_sel_ar; /* (attack state) */
uint8_t eg_sh_dr; /* (decay state) */
uint8_t eg_sel_dr; /* (decay state) */
uint8_t eg_sh_rr; /* (release state) */
uint8_t eg_sel_rr; /* (release state) */
uint32_t key; /* 0 = KEY OFF, >0 = KEY ON */
/* LFO */
uint32_t AMmask; /* LFO Amplitude Modulation enable mask */
uint8_t vib; /* LFO Phase Modulation enable flag (active high)*/
/* waveform select */
uint16_t wavetable;
};
struct OPL_CH
{
OPL_SLOT SLOT[2];
/* phase generator state */
uint32_t block_fnum; /* block+fnum */
uint32_t fc; /* Freq. Increment base */
uint32_t ksl_base; /* KeyScaleLevel Base step */
uint8_t kcode; /* key code (for key scaling) */
float LeftVol; /* volumes for stereo panning */
float RightVol;
};
/* OPL state */
struct FM_OPL
{
/* FM channel slots */
OPL_CH P_CH[9]; /* OPL/OPL2 chips have 9 channels*/
uint32_t eg_cnt; /* global envelope generator counter */
uint32_t eg_timer; /* global envelope generator counter works at frequency = chipclock/72 */
uint32_t eg_timer_add; /* step of eg_timer */
uint32_t eg_timer_overflow; /* envelope generator timer overflows every 1 sample (on real chip) */
uint8_t rhythm; /* Rhythm mode */
uint32_t fn_tab[1024]; /* fnumber->increment counter */
/* LFO */
uint8_t lfo_am_depth;
uint8_t lfo_pm_depth_range;
uint32_t lfo_am_cnt;
uint32_t lfo_am_inc;
uint32_t lfo_pm_cnt;
uint32_t lfo_pm_inc;
uint32_t noise_rng; /* 23 bit noise shift register */
uint32_t noise_p; /* current noise 'phase' */
uint32_t noise_f; /* current noise period */
uint8_t wavesel; /* waveform select enable flag */
int T[2]; /* timer counters */
uint8_t st[2]; /* timer enable */
uint8_t address; /* address register */
uint8_t status; /* status flag */
uint8_t statusmask; /* status mask */
uint8_t mode; /* Reg.08 : CSM,notesel,etc. */
bool IsStereo; /* Write stereo output */
};
/* mapping of register number (offset) to slot number used by the emulator */
static const int slot_array[32]=
{
0, 2, 4, 1, 3, 5,-1,-1,
6, 8,10, 7, 9,11,-1,-1,
12,14,16,13,15,17,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1
};
/* key scale level */
/* table is 3dB/octave , DV converts this into 6dB/octave */
/* 0.1875 is bit 0 weight of the envelope counter (volume) expressed in the 'decibel' scale */
#define DV (0.1875/2.0)
static const uint32_t ksl_tab[8*16]=
{
/* OCT 0 */
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
/* OCT 1 */
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(0.750/DV), uint32_t(1.125/DV), uint32_t(1.500/DV),
uint32_t(1.875/DV), uint32_t(2.250/DV), uint32_t(2.625/DV), uint32_t(3.000/DV),
/* OCT 2 */
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
uint32_t(0.000/DV), uint32_t(1.125/DV), uint32_t(1.875/DV), uint32_t(2.625/DV),
uint32_t(3.000/DV), uint32_t(3.750/DV), uint32_t(4.125/DV), uint32_t(4.500/DV),
uint32_t(4.875/DV), uint32_t(5.250/DV), uint32_t(5.625/DV), uint32_t(6.000/DV),
/* OCT 3 */
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(1.875/DV),
uint32_t(3.000/DV), uint32_t(4.125/DV), uint32_t(4.875/DV), uint32_t(5.625/DV),
uint32_t(6.000/DV), uint32_t(6.750/DV), uint32_t(7.125/DV), uint32_t(7.500/DV),
uint32_t(7.875/DV), uint32_t(8.250/DV), uint32_t(8.625/DV), uint32_t(9.000/DV),
/* OCT 4 */
uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(3.000/DV), uint32_t(4.875/DV),
uint32_t(6.000/DV), uint32_t(7.125/DV), uint32_t(7.875/DV), uint32_t(8.625/DV),
uint32_t(9.000/DV), uint32_t(9.750/DV),uint32_t(10.125/DV),uint32_t(10.500/DV),
uint32_t(10.875/DV),uint32_t(11.250/DV),uint32_t(11.625/DV),uint32_t(12.000/DV),
/* OCT 5 */
uint32_t(0.000/DV), uint32_t(3.000/DV), uint32_t(6.000/DV), uint32_t(7.875/DV),
uint32_t(9.000/DV),uint32_t(10.125/DV),uint32_t(10.875/DV),uint32_t(11.625/DV),
uint32_t(12.000/DV),uint32_t(12.750/DV),uint32_t(13.125/DV),uint32_t(13.500/DV),
uint32_t(13.875/DV),uint32_t(14.250/DV),uint32_t(14.625/DV),uint32_t(15.000/DV),
/* OCT 6 */
uint32_t(0.000/DV), uint32_t(6.000/DV), uint32_t(9.000/DV),uint32_t(10.875/DV),
uint32_t(12.000/DV),uint32_t(13.125/DV),uint32_t(13.875/DV),uint32_t(14.625/DV),
uint32_t(15.000/DV),uint32_t(15.750/DV),uint32_t(16.125/DV),uint32_t(16.500/DV),
uint32_t(16.875/DV),uint32_t(17.250/DV),uint32_t(17.625/DV),uint32_t(18.000/DV),
/* OCT 7 */
uint32_t(0.000/DV), uint32_t(9.000/DV),uint32_t(12.000/DV),uint32_t(13.875/DV),
uint32_t(15.000/DV),uint32_t(16.125/DV),uint32_t(16.875/DV),uint32_t(17.625/DV),
uint32_t(18.000/DV),uint32_t(18.750/DV),uint32_t(19.125/DV),uint32_t(19.500/DV),
uint32_t(19.875/DV),uint32_t(20.250/DV),uint32_t(20.625/DV),uint32_t(21.000/DV)
};
#undef DV
/* 0 / 3.0 / 1.5 / 6.0 dB/OCT */
static const uint32_t ksl_shift[4] = { 31, 1, 2, 0 };
/* sustain level table (3dB per step) */
/* 0 - 15: 0, 3, 6, 9,12,15,18,21,24,27,30,33,36,39,42,93 (dB)*/
#define SC(db) (uint32_t) ( db * (2.0/ENV_STEP) )
static const uint32_t sl_tab[16]={
SC( 0),SC( 1),SC( 2),SC(3 ),SC(4 ),SC(5 ),SC(6 ),SC( 7),
SC( 8),SC( 9),SC(10),SC(11),SC(12),SC(13),SC(14),SC(31)
};
#undef SC
#define RATE_STEPS (8)
static const unsigned char eg_inc[15*RATE_STEPS]={
/*cycle:0 1 2 3 4 5 6 7*/
/* 0 */ 0,1, 0,1, 0,1, 0,1, /* rates 00..12 0 (increment by 0 or 1) */
/* 1 */ 0,1, 0,1, 1,1, 0,1, /* rates 00..12 1 */
/* 2 */ 0,1, 1,1, 0,1, 1,1, /* rates 00..12 2 */
/* 3 */ 0,1, 1,1, 1,1, 1,1, /* rates 00..12 3 */
/* 4 */ 1,1, 1,1, 1,1, 1,1, /* rate 13 0 (increment by 1) */
/* 5 */ 1,1, 1,2, 1,1, 1,2, /* rate 13 1 */
/* 6 */ 1,2, 1,2, 1,2, 1,2, /* rate 13 2 */
/* 7 */ 1,2, 2,2, 1,2, 2,2, /* rate 13 3 */
/* 8 */ 2,2, 2,2, 2,2, 2,2, /* rate 14 0 (increment by 2) */
/* 9 */ 2,2, 2,4, 2,2, 2,4, /* rate 14 1 */
/*10 */ 2,4, 2,4, 2,4, 2,4, /* rate 14 2 */
/*11 */ 2,4, 4,4, 2,4, 4,4, /* rate 14 3 */
/*12 */ 4,4, 4,4, 4,4, 4,4, /* rates 15 0, 15 1, 15 2, 15 3 (increment by 4) */
/*13 */ 8,8, 8,8, 8,8, 8,8, /* rates 15 2, 15 3 for attack */
/*14 */ 0,0, 0,0, 0,0, 0,0, /* infinity rates for attack and decay(s) */
};
#define O(a) (a*RATE_STEPS)
/*note that there is no O(13) in this table - it's directly in the code */
static const unsigned char eg_rate_select[16+64+16]={ /* Envelope Generator rates (16 + 64 rates + 16 RKS) */
/* 16 infinite time rates */
O(14),O(14),O(14),O(14),O(14),O(14),O(14),O(14),
O(14),O(14),O(14),O(14),O(14),O(14),O(14),O(14),
/* rates 00-12 */
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
O( 0),O( 1),O( 2),O( 3),
/* rate 13 */
O( 4),O( 5),O( 6),O( 7),
/* rate 14 */
O( 8),O( 9),O(10),O(11),
/* rate 15 */
O(12),O(12),O(12),O(12),
/* 16 dummy rates (same as 15 3) */
O(12),O(12),O(12),O(12),O(12),O(12),O(12),O(12),
O(12),O(12),O(12),O(12),O(12),O(12),O(12),O(12),
};
#undef O
/*rate 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 */
/*shift 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0 */
/*mask 4095, 2047, 1023, 511, 255, 127, 63, 31, 15, 7, 3, 1, 0, 0, 0, 0 */
#define O(a) (a*1)
static const unsigned char eg_rate_shift[16+64+16]={ /* Envelope Generator counter shifts (16 + 64 rates + 16 RKS) */
/* 16 infinite time rates */
O(0),O(0),O(0),O(0),O(0),O(0),O(0),O(0),
O(0),O(0),O(0),O(0),O(0),O(0),O(0),O(0),
/* rates 00-12 */
O(12),O(12),O(12),O(12),
O(11),O(11),O(11),O(11),
O(10),O(10),O(10),O(10),
O( 9),O( 9),O( 9),O( 9),
O( 8),O( 8),O( 8),O( 8),
O( 7),O( 7),O( 7),O( 7),
O( 6),O( 6),O( 6),O( 6),
O( 5),O( 5),O( 5),O( 5),
O( 4),O( 4),O( 4),O( 4),
O( 3),O( 3),O( 3),O( 3),
O( 2),O( 2),O( 2),O( 2),
O( 1),O( 1),O( 1),O( 1),
O( 0),O( 0),O( 0),O( 0),
/* rate 13 */
O( 0),O( 0),O( 0),O( 0),
/* rate 14 */
O( 0),O( 0),O( 0),O( 0),
/* rate 15 */
O( 0),O( 0),O( 0),O( 0),
/* 16 dummy rates (same as 15 3) */
O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),
O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),
};
#undef O
/* multiple table */
#define ML 2
static const uint8_t mul_tab[16]= {
/* 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,10,12,12,15,15 */
uint8_t(0.50*ML), uint8_t(1.00*ML), uint8_t(2.00*ML), uint8_t(3.00*ML), uint8_t(4.00*ML), uint8_t(5.00*ML), uint8_t(6.00*ML), uint8_t(7.00*ML),
uint8_t(8.00*ML), uint8_t(9.00*ML),uint8_t(10.00*ML),uint8_t(10.00*ML),uint8_t(12.00*ML),uint8_t(12.00*ML),uint8_t(15.00*ML),uint8_t(15.00*ML)
};
#undef ML
/* TL_TAB_LEN is calculated as:
* 12 - sinus amplitude bits (Y axis)
* 2 - sinus sign bit (Y axis)
* TL_RES_LEN - sinus resolution (X axis)
*/
#define TL_TAB_LEN (12*2*TL_RES_LEN)
static signed int tl_tab[TL_TAB_LEN];
#define ENV_QUIET (TL_TAB_LEN>>4)
/* sin waveform table in 'decibel' scale */
/* four waveforms on OPL2 type chips */
static unsigned int sin_tab[SIN_LEN * 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_t 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_t 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*/
};
/* work table */
static signed int phase_modulation; /* phase modulation input (SLOT 2) */
static signed int output;
static uint32_t LFO_AM;
static int32_t LFO_PM;
static bool CalcVoice (FM_OPL *OPL, int voice, float *buffer, int length);
static bool CalcRhythm (FM_OPL *OPL, float *buffer, int length);
/* status set and IRQ handling */
static 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;
}
}
}
/* status reset and IRQ handling */
static 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;
}
}
}
/* IRQ mask set */
static 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 */
static inline void advance_lfo(FM_OPL *OPL)
{
uint8_t tmp;
/* LFO */
OPL->lfo_am_cnt += OPL->lfo_am_inc;
if (OPL->lfo_am_cnt >= (uint32_t)(LFO_AM_TAB_ELEMENTS<<LFO_SH) ) /* lfo_am_table is 210 elements long */
OPL->lfo_am_cnt -= (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 */
static inline void advance(FM_OPL *OPL, int loch, int hich)
{
OPL_CH *CH;
OPL_SLOT *op;
int i;
OPL->eg_timer += OPL->eg_timer_add;
loch *= 2;
hich *= 2;
while (OPL->eg_timer >= OPL->eg_timer_overflow)
{
OPL->eg_timer -= OPL->eg_timer_overflow;
OPL->eg_cnt++;
for (i = loch; i <= hich + 1; 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_t)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;
}
/* Phase Generator */
if(op->vib)
{
uint8_t 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;
}
else /* LFO phase modulation = zero */
{
op->Cnt += op->Incr;
}
}
else /* LFO phase modulation disabled for this operator */
{
op->Cnt += op->Incr;
}
}
}
}
static inline void advance_noise(FM_OPL *OPL)
{
int i;
/* 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_t 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--;
}
}
static inline signed int op_calc(uint32_t phase, unsigned int env, signed int pm, unsigned int wave_tab)
{
uint32_t 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];
}
static inline signed int op_calc1(uint32_t phase, unsigned int env, signed int pm, unsigned int wave_tab)
{
uint32_t p;
p = (env<<4) + sin_tab[wave_tab + ((((signed int)((phase & ~FREQ_MASK) + pm )) >> FREQ_SH ) & SIN_MASK) ];
if (p >= TL_TAB_LEN)
return 0;
return tl_tab[p];
}
#define volume_calc(OP) ((OP)->TLL + ((uint32_t)(OP)->volume) + (LFO_AM & (OP)->AMmask))
/* calculate output */
static inline float 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 += op_calc(SLOT->Cnt, env, phase_modulation, SLOT->wavetable);
/* [RH] Convert to floating point. */
return float(output) / 10240;
}
return 0;
}
/*
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 */
static inline void 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 += 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(&CH[7].SLOT[SLOT1]);
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 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>7)&1;
unsigned char bit3 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>3)&1;
unsigned char bit2 = ((CH[7].SLOT[SLOT1].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_t phase = res1 ? (0x200|(0xd0>>2)) : 0xd0;
/* enable gate based on frequency of operator 2 in channel 8 */
unsigned char bit5e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>5)&1;
unsigned char bit3e= ((CH[8].SLOT[SLOT2].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 += op_calc(phase<<FREQ_SH, env, 0, CH[7].SLOT[SLOT1].wavetable) * 2;
}
/* Snare Drum (verified on real YM3812) */
env = volume_calc(&CH[7].SLOT[SLOT2]);
if( env < ENV_QUIET )
{
/* base frequency derived from operator 1 in channel 7 */
unsigned char bit8 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>8)&1;
/* when bit8 = 0 phase = 0x100; */
/* when bit8 = 1 phase = 0x200; */
uint32_t 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 += op_calc(phase<<FREQ_SH, env, 0, CH[7].SLOT[SLOT2].wavetable) * 2;
}
/* Tom Tom (verified on real YM3812) */
env = volume_calc(&CH[8].SLOT[SLOT1]);
if( env < ENV_QUIET )
output += op_calc(CH[8].SLOT[SLOT1].Cnt, env, 0, CH[8].SLOT[SLOT2].wavetable) * 2;
/* Top Cymbal (verified on real YM3812) */
env = volume_calc(&CH[8].SLOT[SLOT2]);
if( env < ENV_QUIET )
{
/* base frequency derived from operator 1 in channel 7 */
unsigned char bit7 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>7)&1;
unsigned char bit3 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>3)&1;
unsigned char bit2 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>2)&1;
unsigned char res1 = (bit2 ^ bit7) | bit3;
/* when res1 = 0 phase = 0x000 | 0x100; */
/* when res1 = 1 phase = 0x200 | 0x100; */
uint32_t phase = res1 ? 0x300 : 0x100;
/* enable gate based on frequency of operator 2 in channel 8 */
unsigned char bit5e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>5)&1;
unsigned char bit3e= ((CH[8].SLOT[SLOT2].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 += op_calc(phase<<FREQ_SH, env, 0, CH[8].SLOT[SLOT2].wavetable) * 2;
}
}
/* generic table initialize */
static void init_tables(void)
{
signed int i,x;
signed int n;
double o,m;
/* We only need to do this once. */
static bool did_init = false;
if (did_init)
{
return;
}
for (x=0; x<TL_RES_LEN; x++)
{
m = (1<<16) / pow(2.0, (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 */
n = (n+1)>>1; /* round to nearest */
/* 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;
}
}
for (i=0; i<SIN_LEN; i++)
{
/* non-standard sinus */
m = sin( ((i*2)+1) * 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(2.0); /* convert to 'decibels' */
else
o = 8*log(-1.0/m)/log(2.0); /* 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 );
}
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)];
}
did_init = true;
}
static void OPL_initalize(FM_OPL *OPL)
{
int i;
/* make fnumber -> increment counter table */
for( i=0 ; i < 1024 ; i++ )
{
/* opn phase increment counter = 20bit */
OPL->fn_tab[i] = (uint32_t)( (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 = uint32_t((1.0 / 64.0 ) * (1<<LFO_SH) * OPL_FREQBASE);
/* Vibrato: 8 output levels (triangle waveform); 1 level takes 1024 samples */
OPL->lfo_pm_inc = uint32_t((1.0 / 1024.0) * (1<<LFO_SH) * OPL_FREQBASE);
OPL->eg_timer_add = uint32_t((1<<EG_SH) * OPL_FREQBASE);
OPL->eg_timer_overflow = uint32_t(( 1 ) * (1<<EG_SH));
// [RH] Support full MIDI panning. (But default to mono and center panning.)
OPL->IsStereo = false;
for (int i = 0; i < 9; ++i)
{
OPL->P_CH[i].LeftVol = (float)CENTER_PANNING_POWER;
OPL->P_CH[i].RightVol = (float)CENTER_PANNING_POWER;
}
}
static inline void FM_KEYON(OPL_SLOT *SLOT, uint32_t key_set)
{
if( !SLOT->key )
{
/* restart Phase Generator */
SLOT->Cnt = 0;
/* phase -> Attack */
SLOT->state = EG_ATT;
}
SLOT->key |= key_set;
}
static inline void FM_KEYOFF(OPL_SLOT *SLOT, uint32_t 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) */
static 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 */
static 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 */
static 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];
SLOT->ksl = ksl_shift[v >> 6];
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 */
static 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 */
static 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 */
static void WriteRegister(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 */
OPL->wavesel = v&0x20;
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-0x08); /* don't reset BFRDY flag or we will have to call deltat module to set the flag */
}
else
{ /* set IRQ mask ,timer enable*/
uint8_t st1 = v&1;
uint8_t st2 = (v>>1)&1;
/* IRQRST,T1MSK,t2MSK,EOSMSK,BRMSK,x,ST2,ST1 */
OPL_STATUS_RESET(OPL, v & (0x78-0x08) );
OPL_STATUSMASK_SET(OPL, (~v) & 0x78 );
/* timer 2 */
if(OPL->st[1] != st2)
{
OPL->st[1] = st2;
}
/* timer 1 */
if(OPL->st[0] != st1)
{
OPL->st[0] = st1;
}
}
break;
case 0x08: /* MODE,DELTA-T control 2 : 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], 2);
FM_KEYON (&OPL->P_CH[6].SLOT[SLOT2], 2);
}
else
{
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1],~2);
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2],~2);
}
/* HH key on/off */
if(v&0x01) FM_KEYON (&OPL->P_CH[7].SLOT[SLOT1], 2);
else FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1],~2);
/* SD key on/off */
if(v&0x08) FM_KEYON (&OPL->P_CH[7].SLOT[SLOT2], 2);
else FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2],~2);
/* TOM key on/off */
if(v&0x04) FM_KEYON (&OPL->P_CH[8].SLOT[SLOT1], 2);
else FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1],~2);
/* TOP-CY key on/off */
if(v&0x02) FM_KEYON (&OPL->P_CH[8].SLOT[SLOT2], 2);
else FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2],~2);
}
else
{
/* BD key off */
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1],~2);
FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2],~2);
/* HH key off */
FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1],~2);
/* SD key off */
FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2],~2);
/* TOM key off */
FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1],~2);
/* TOP-CY off */
FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2],~2);
}
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], 1);
FM_KEYON (&CH->SLOT[SLOT2], 1);
}
else
{
FM_KEYOFF(&CH->SLOT[SLOT1],~1);
FM_KEYOFF(&CH->SLOT[SLOT2],~1);
}
}
/* update */
if(CH->block_fnum != (uint32_t)block_fnum)
{
uint8_t 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 : &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;
}
}
static void 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 */
WriteRegister(OPL,0x01,0); /* wavesel disable */
WriteRegister(OPL,0x02,0); /* Timer1 */
WriteRegister(OPL,0x03,0); /* Timer2 */
WriteRegister(OPL,0x04,0); /* IRQ mask clear */
for(i = 0xff ; i >= 0x20 ; i-- ) WriteRegister(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;
}
}
}
class YM3812 : public OPLEmul
{
private:
FM_OPL Chip;
public:
/* Create one of virtual YM3812 */
YM3812(bool stereo)
{
init_tables();
/* clear */
memset(&Chip, 0, sizeof(Chip));
/* init global tables */
OPL_initalize(&Chip);
Chip.IsStereo = stereo;
Reset();
}
/* YM3812 I/O interface */
void WriteReg(int reg, int v)
{
WriteRegister(&Chip, reg & 0xff, v);
}
void Reset()
{
OPLResetChip(&Chip);
}
/* [RH] Full support for MIDI panning */
void SetPanning(int c, float left, float right)
{
Chip.P_CH[c].LeftVol = left;
Chip.P_CH[c].RightVol = right;
}
/*
** Generate samples for one of the YM3812's
**
** '*buffer' is the output buffer pointer
** 'length' is the number of samples that should be generated
*/
void Update(float *buffer, int length)
{
int i;
uint8_t rhythm = Chip.rhythm&0x20;
uint32_t lfo_am_cnt_bak = Chip.lfo_am_cnt;
uint32_t eg_timer_bak = Chip.eg_timer;
uint32_t eg_cnt_bak = Chip.eg_cnt;
uint32_t lfo_am_cnt_out = lfo_am_cnt_bak;
uint32_t eg_timer_out = eg_timer_bak;
uint32_t eg_cnt_out = eg_cnt_bak;
for (i = 0; i <= (rhythm ? 5 : 8); ++i)
{
Chip.lfo_am_cnt = lfo_am_cnt_bak;
Chip.eg_timer = eg_timer_bak;
Chip.eg_cnt = eg_cnt_bak;
if (CalcVoice (&Chip, i, buffer, length))
{
lfo_am_cnt_out = Chip.lfo_am_cnt;
eg_timer_out = Chip.eg_timer;
eg_cnt_out = Chip.eg_cnt;
}
}
Chip.lfo_am_cnt = lfo_am_cnt_out;
Chip.eg_timer = eg_timer_out;
Chip.eg_cnt = eg_cnt_out;
if (rhythm) /* Rhythm part */
{
Chip.lfo_am_cnt = lfo_am_cnt_bak;
Chip.eg_timer = eg_timer_bak;
Chip.eg_cnt = eg_cnt_bak;
CalcRhythm (&Chip, buffer, length);
}
}
std::string GetVoiceString(void *chip)
{
FM_OPL *OPL = (FM_OPL *)chip;
char out[9*3];
for (int i = 0; i <= 8; ++i)
{
int color;
if (OPL != NULL && (OPL->P_CH[i].SLOT[0].state != EG_OFF || OPL->P_CH[i].SLOT[1].state != EG_OFF))
{
color = 'D'; // Green means in use
}
else
{
color = 'A'; // Brick means free
}
out[i*3+0] = '\x1c';
out[i*3+1] = color;
out[i*3+2] = '*';
}
return std::string (out, 9*3);
}
};
OPLEmul *YM3812Create(bool stereo)
{
/* emulator create */
return new YM3812(stereo);
}
// [RH] Render a whole voice at once. If nothing else, it lets us avoid
// wasting a lot of time on voices that aren't playing anything.
static bool CalcVoice (FM_OPL *OPL, int voice, float *buffer, int length)
{
OPL_CH *const CH = &OPL->P_CH[voice];
int i;
if (CH->SLOT[0].state == EG_OFF && CH->SLOT[1].state == EG_OFF)
{ // Voice is not playing, so don't do anything for it
return false;
}
for (i = 0; i < length; ++i)
{
advance_lfo(OPL);
output = 0;
float sample = OPL_CALC_CH(CH);
if (!OPL->IsStereo)
{
buffer[i] += sample;
}
else
{
buffer[i*2] += sample * CH->LeftVol;
buffer[i*2+1] += sample * CH->RightVol;
}
advance(OPL, voice, voice);
}
return true;
}
static bool CalcRhythm (FM_OPL *OPL, float *buffer, int length)
{
int i;
for (i = 0; i < length; ++i)
{
advance_lfo(OPL);
output = 0;
OPL_CALC_RH(&OPL->P_CH[0], OPL->noise_rng & 1);
/* [RH] Convert to floating point. */
float sample = float(output) / 10240;
if (!OPL->IsStereo)
{
buffer[i] += sample;
}
else
{
// [RH] Always use center panning for rhythm.
// The MIDI player doesn't use the rhythm section anyway.
buffer[i*2] += sample * CENTER_PANNING_POWER;
buffer[i*2+1] += sample * CENTER_PANNING_POWER;
}
advance(OPL, 6, 8);
advance_noise(OPL);
}
return true;
}
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