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/* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
* Copyright (C) 2011, 2012, 2013 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
*
* This program 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 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//#include <cmath>
//#include <cstdlib>
//#include <cstring>
#include "mt32emu.h"
#include "mmath.h"
namespace MT32Emu {
const Tables &Tables::getInstance() {
static const Tables instance;
return instance;
}
Tables::Tables() {
int lf;
for (lf = 0; lf <= 100; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
float fVal = (2.0f - LOG10F((float)lf + 1.0f)) * 128.0f;
int val = (int)(fVal + 1.0);
if (val > 255) {
val = 255;
}
levelToAmpSubtraction[lf] = (Bit8u)val;
}
envLogarithmicTime[0] = 64;
for (lf = 1; lf <= 255; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
envLogarithmicTime[lf] = (Bit8u)ceil(64.0f + LOG2F((float)lf) * 8.0f);
}
#ifdef EMULATE_LAPC_I // Dummy #ifdef - we'll have runtime emulation mode selection in future.
// CONFIRMED: Based on a table found by Mok in the LAPC-I control ROM
// Note that this matches the MT-32 table, but with the values clamped to a maximum of 8.
memset(masterVolToAmpSubtraction, 8, 71);
memset(masterVolToAmpSubtraction + 71, 7, 3);
memset(masterVolToAmpSubtraction + 74, 6, 4);
memset(masterVolToAmpSubtraction + 78, 5, 3);
memset(masterVolToAmpSubtraction + 81, 4, 4);
memset(masterVolToAmpSubtraction + 85, 3, 3);
memset(masterVolToAmpSubtraction + 88, 2, 4);
memset(masterVolToAmpSubtraction + 92, 1, 4);
memset(masterVolToAmpSubtraction + 96, 0, 5);
#else
// CONFIRMED: Based on a table found by Mok in the MT-32 control ROM
masterVolToAmpSubtraction[0] = 255;
for (int masterVol = 1; masterVol <= 100; masterVol++) {
masterVolToAmpSubtraction[masterVol] = (int)(106.31 - 16.0f * LOG2F((float)masterVol));
}
#endif
for (int i = 0; i <= 100; i++) {
pulseWidth100To255[i] = (int)(i * 255 / 100.0f + 0.5f);
//synth->printDebug("%d: %d", i, pulseWidth100To255[i]);
}
// The LA32 chip contains an exponent table inside. The table contains 12-bit integer values.
// The actual table size is 512 rows. The 9 higher bits of the fractional part of the argument are used as a lookup address.
// To improve the precision of computations, the lower bits are supposed to be used for interpolation as the LA32 chip also
// contains another 512-row table with inverted differences between the main table values.
for (int i = 0; i < 512; i++) {
exp9[i] = Bit16u(8191.5f - EXP2F(13.0f + ~i / 512.0f));
}
// There is a logarithmic sine table inside the LA32 chip. The table contains 13-bit integer values.
for (int i = 1; i < 512; i++) {
logsin9[i] = Bit16u(0.5f - LOG2F(sin((i + 0.5f) / 1024.0f * FLOAT_PI)) * 1024.0f);
}
// The very first value is clamped to the maximum possible 13-bit integer
logsin9[0] = 8191;
// found from sample analysis
static const Bit8u resAmpDecayFactorTable[] = {31, 16, 12, 8, 5, 3, 2, 1};
resAmpDecayFactor = resAmpDecayFactorTable;
}
}
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