mirror of
https://github.com/libretro/scummvm.git
synced 2025-04-11 11:11:20 +00:00
021a828e2e
This commit adds a mediator class to decouple the CMS emulator from the engines that use it. This allows for easier updating or replacement of the emulator or addition of new emulators. It also enables using the emulator via a callback mechanism.
375 lines
11 KiB
C++
375 lines
11 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "audio/softsynth/cms.h"
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#include "audio/null.h"
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#include "common/textconsole.h"
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#include "common/translation.h"
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#include "common/debug.h"
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// CMS/Gameblaster Emulation taken from DosBox
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#define LEFT 0x00
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#define RIGHT 0x01
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static const byte envelope[8][64] = {
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/* zero amplitude */
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{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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/* maximum amplitude */
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{15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
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15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
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15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
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15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15 },
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/* single decay */
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{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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/* repetitive decay */
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{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
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/* single triangular */
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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/* repetitive triangular */
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
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/* single attack */
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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/* repetitive attack */
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15 }
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};
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static const int amplitude_lookup[16] = {
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0*32767/16, 1*32767/16, 2*32767/16, 3*32767/16,
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4*32767/16, 5*32767/16, 6*32767/16, 7*32767/16,
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8*32767/16, 9*32767/16, 10*32767/16, 11*32767/16,
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12*32767/16, 13*32767/16, 14*32767/16, 15*32767/16
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};
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void CMSEmulator::portWrite(int port, int val) {
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switch (port) {
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case 0x220:
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portWriteIntern(0, 1, val);
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break;
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case 0x221:
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_saa1099[0].selected_reg = val & 0x1f;
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if (_saa1099[0].selected_reg == 0x18 || _saa1099[0].selected_reg == 0x19) {
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/* clock the envelope channels */
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if (_saa1099[0].env_clock[0])
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envelope(0, 0);
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if (_saa1099[0].env_clock[1])
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envelope(0, 1);
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}
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break;
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case 0x222:
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portWriteIntern(1, 1, val);
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break;
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case 0x223:
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_saa1099[1].selected_reg = val & 0x1f;
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if (_saa1099[1].selected_reg == 0x18 || _saa1099[1].selected_reg == 0x19) {
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/* clock the envelope channels */
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if (_saa1099[1].env_clock[0])
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envelope(1, 0);
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if (_saa1099[1].env_clock[1])
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envelope(1, 1);
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}
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break;
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default:
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warning("CMSEmulator got port: 0x%X", port);
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break;
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}
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}
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void CMSEmulator::readBuffer(int16 *buffer, const int numSamples) {
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update(0, &buffer[0], numSamples);
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update(1, &buffer[0], numSamples);
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}
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void CMSEmulator::reset() {
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memset(_saa1099, 0, sizeof(SAA1099) * 2);
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}
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void CMSEmulator::envelope(int chip, int ch) {
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SAA1099 *saa = &_saa1099[chip];
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if (saa->env_enable[ch]) {
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int step, mode, mask;
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mode = saa->env_mode[ch];
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/* step from 0..63 and then loop in steps 32..63 */
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step = saa->env_step[ch] = ((saa->env_step[ch] + 1) & 0x3f) | (saa->env_step[ch] & 0x20);
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mask = 15;
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if (saa->env_bits[ch])
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mask &= ~1; /* 3 bit resolution, mask LSB */
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saa->channels[ch*3+0].envelope[ LEFT] =
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saa->channels[ch*3+1].envelope[ LEFT] =
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saa->channels[ch*3+2].envelope[ LEFT] = ::envelope[mode][step] & mask;
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if (saa->env_reverse_right[ch] & 0x01) {
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saa->channels[ch*3+0].envelope[RIGHT] =
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saa->channels[ch*3+1].envelope[RIGHT] =
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saa->channels[ch*3+2].envelope[RIGHT] = (15 - ::envelope[mode][step]) & mask;
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} else {
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saa->channels[ch*3+0].envelope[RIGHT] =
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saa->channels[ch*3+1].envelope[RIGHT] =
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saa->channels[ch*3+2].envelope[RIGHT] = ::envelope[mode][step] & mask;
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}
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} else {
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/* envelope mode off, set all envelope factors to 16 */
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saa->channels[ch*3+0].envelope[ LEFT] =
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saa->channels[ch*3+1].envelope[ LEFT] =
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saa->channels[ch*3+2].envelope[ LEFT] =
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saa->channels[ch*3+0].envelope[RIGHT] =
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saa->channels[ch*3+1].envelope[RIGHT] =
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saa->channels[ch*3+2].envelope[RIGHT] = 16;
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}
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}
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void CMSEmulator::update(int chip, int16 *buffer, int length) {
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struct SAA1099 *saa = &_saa1099[chip];
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int j, ch;
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if (chip == 0) {
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memset(buffer, 0, sizeof(int16)*length*2);
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}
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/* if the channels are disabled we're done */
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if (!saa->all_ch_enable) {
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return;
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}
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for (ch = 0; ch < 2; ch++) {
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switch (saa->noise_params[ch]) {
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case 0: saa->noise[ch].freq = 31250.0 * 2; break;
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case 1: saa->noise[ch].freq = 15625.0 * 2; break;
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case 2: saa->noise[ch].freq = 7812.5 * 2; break;
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case 3: saa->noise[ch].freq = saa->channels[ch * 3].freq; break;
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default: break;
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}
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}
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/* fill all data needed */
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for (j = 0; j < length; ++j) {
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int output_l = 0, output_r = 0;
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/* for each channel */
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for (ch = 0; ch < 6; ch++) {
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if (saa->channels[ch].freq == 0.0)
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saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
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(511.0 - (double)saa->channels[ch].frequency);
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/* check the actual position in the square wave */
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saa->channels[ch].counter -= saa->channels[ch].freq;
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while (saa->channels[ch].counter < 0) {
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/* calculate new frequency now after the half wave is updated */
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saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
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(511.0 - (double)saa->channels[ch].frequency);
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saa->channels[ch].counter += _sampleRate;
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saa->channels[ch].level ^= 1;
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/* eventually clock the envelope counters */
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if (ch == 1 && saa->env_clock[0] == 0)
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envelope(chip, 0);
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if (ch == 4 && saa->env_clock[1] == 0)
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envelope(chip, 1);
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}
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/* if the noise is enabled */
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if (saa->channels[ch].noise_enable) {
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/* if the noise level is high (noise 0: chan 0-2, noise 1: chan 3-5) */
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if (saa->noise[ch/3].level & 1) {
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/* subtract to avoid overflows, also use only half amplitude */
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output_l -= saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16 / 2;
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output_r -= saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16 / 2;
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}
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}
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/* if the square wave is enabled */
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if (saa->channels[ch].freq_enable) {
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/* if the channel level is high */
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if (saa->channels[ch].level & 1) {
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output_l += saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16;
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output_r += saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16;
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}
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}
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}
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for (ch = 0; ch < 2; ch++) {
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/* check the actual position in noise generator */
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saa->noise[ch].counter -= saa->noise[ch].freq;
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while (saa->noise[ch].counter < 0) {
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saa->noise[ch].counter += _sampleRate;
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if (((saa->noise[ch].level & 0x4000) == 0) == ((saa->noise[ch].level & 0x0040) == 0) )
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saa->noise[ch].level = (saa->noise[ch].level << 1) | 1;
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else
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saa->noise[ch].level <<= 1;
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}
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}
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/* write sound data to the buffer */
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buffer[j*2+0] = CLIP<int>(buffer[j*2+0] + output_l / 6, -32768, 32767);
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buffer[j*2+1] = CLIP<int>(buffer[j*2+1] + output_r / 6, -32768, 32767);
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}
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}
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void CMSEmulator::portWriteIntern(int chip, int offset, int data) {
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SAA1099 *saa = &_saa1099[chip];
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int reg = saa->selected_reg;
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int ch;
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switch (reg) {
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/* channel i amplitude */
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case 0x00:
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case 0x01:
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case 0x02:
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case 0x03:
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case 0x04:
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case 0x05:
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ch = reg & 7;
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saa->channels[ch].amplitude[LEFT] = amplitude_lookup[data & 0x0f];
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saa->channels[ch].amplitude[RIGHT] = amplitude_lookup[(data >> 4) & 0x0f];
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break;
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/* channel i frequency */
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case 0x08:
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case 0x09:
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case 0x0a:
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case 0x0b:
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case 0x0c:
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case 0x0d:
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ch = reg & 7;
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saa->channels[ch].frequency = data & 0xff;
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break;
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/* channel i octave */
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case 0x10:
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case 0x11:
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case 0x12:
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ch = (reg - 0x10) << 1;
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saa->channels[ch + 0].octave = data & 0x07;
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saa->channels[ch + 1].octave = (data >> 4) & 0x07;
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break;
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/* channel i frequency enable */
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case 0x14:
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saa->channels[0].freq_enable = data & 0x01;
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saa->channels[1].freq_enable = data & 0x02;
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saa->channels[2].freq_enable = data & 0x04;
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saa->channels[3].freq_enable = data & 0x08;
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saa->channels[4].freq_enable = data & 0x10;
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saa->channels[5].freq_enable = data & 0x20;
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break;
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/* channel i noise enable */
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case 0x15:
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saa->channels[0].noise_enable = data & 0x01;
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saa->channels[1].noise_enable = data & 0x02;
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saa->channels[2].noise_enable = data & 0x04;
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saa->channels[3].noise_enable = data & 0x08;
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saa->channels[4].noise_enable = data & 0x10;
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saa->channels[5].noise_enable = data & 0x20;
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break;
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/* noise generators parameters */
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case 0x16:
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saa->noise_params[0] = data & 0x03;
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saa->noise_params[1] = (data >> 4) & 0x03;
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break;
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/* envelope generators parameters */
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case 0x18:
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case 0x19:
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ch = reg - 0x18;
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saa->env_reverse_right[ch] = data & 0x01;
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saa->env_mode[ch] = (data >> 1) & 0x07;
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saa->env_bits[ch] = data & 0x10;
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saa->env_clock[ch] = data & 0x20;
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saa->env_enable[ch] = data & 0x80;
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/* reset the envelope */
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saa->env_step[ch] = 0;
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break;
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/* channels enable & reset generators */
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case 0x1c:
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saa->all_ch_enable = data & 0x01;
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saa->sync_state = data & 0x02;
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if (data & 0x02) {
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int i;
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/* Synch & Reset generators */
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for (i = 0; i < 6; i++) {
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saa->channels[i].level = 0;
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saa->channels[i].counter = 0.0;
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}
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}
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break;
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default:
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// The CMS allows all registers to be written, so we just output some debug
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// message here
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debug(5, "CMS Unknown write to reg %x with %x",reg, data);
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}
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}
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class CMSMusicPlugin : public NullMusicPlugin {
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public:
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const char *getName() const override {
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return _s("Creative Music System emulator");
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}
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const char *getId() const override {
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return "cms";
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}
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MusicDevices getDevices() const override;
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};
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MusicDevices CMSMusicPlugin::getDevices() const {
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MusicDevices devices;
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devices.push_back(MusicDevice(this, "", MT_CMS));
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return devices;
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}
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//#if PLUGIN_ENABLED_DYNAMIC(CMS)
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//REGISTER_PLUGIN_DYNAMIC(CMS, PLUGIN_TYPE_MUSIC, CMSMusicPlugin);
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//#else
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REGISTER_PLUGIN_STATIC(CMS, PLUGIN_TYPE_MUSIC, CMSMusicPlugin);
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//#endif
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