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scummvm/audio/softsynth/cms.cpp

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/* 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 <http://www.gnu.org/licenses/>.
*
*/
#include "audio/softsynth/cms.h"
#include "audio/null.h"
#include "common/textconsole.h"
#include "common/translation.h"
#include "common/debug.h"
// CMS/Gameblaster Emulation taken from DosBox
#define LEFT 0x00
#define RIGHT 0x01
#define FRAC_ONE_CMS (1UL << 8)
/*#define MASTER_CLOCK 14318180/2 */
#define MASTER_CLOCK (7159090UL * FRAC_ONE_CMS)
static const byte envelope[8][64] = {
/* zero amplitude */
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* maximum amplitude */
{15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15 },
/* single decay */
{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* repetitive decay */
{15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
/* single triangular */
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* repetitive triangular */
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 },
/* single attack */
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
/* repetitive attack */
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15 }
};
static const int amplitude_lookup[16] = {
0*32767/16, 1*32767/16, 2*32767/16, 3*32767/16,
4*32767/16, 5*32767/16, 6*32767/16, 7*32767/16,
8*32767/16, 9*32767/16, 10*32767/16, 11*32767/16,
12*32767/16, 13*32767/16, 14*32767/16, 15*32767/16
};
void DOSBoxCMS::write(int a, int v) {
switch (a-_basePort) {
case 0:
portWriteIntern(0, 0, v);
break;
case 1:
portWriteIntern(0, 1, v);
break;
case 2:
portWriteIntern(1, 0, v);
break;
case 3:
portWriteIntern(1, 1, v);
break;
default:
warning("DOSBoxCMS got port: 0x%X", a);
break;
}
}
void DOSBoxCMS::writeReg(int r, int v) {
int chip = 0;
if (r >= 0x100)
chip = 1;
portWriteIntern(chip, 1, r & 0x1F);
portWriteIntern(chip, 0, v);
}
void DOSBoxCMS::generateSamples(int16 *buffer, const int numSamples) {
update(0, &buffer[0], numSamples);
update(1, &buffer[0], numSamples);
}
bool DOSBoxCMS::init() {
reset();
return true;
}
void DOSBoxCMS::reset() {
memset(_saa1099, 0, sizeof(SAA1099) * 2);
}
void DOSBoxCMS::envelope(int chip, int ch) {
SAA1099 *saa = &_saa1099[chip];
if (saa->env_enable[ch]) {
int step, mode, mask;
mode = saa->env_mode[ch];
/* step from 0..63 and then loop in steps 32..63 */
step = saa->env_step[ch] = ((saa->env_step[ch] + 1) & 0x3f) | (saa->env_step[ch] & 0x20);
mask = 15;
if (saa->env_bits[ch])
mask &= ~1; /* 3 bit resolution, mask LSB */
saa->channels[ch*3+0].envelope[ LEFT] =
saa->channels[ch*3+1].envelope[ LEFT] =
saa->channels[ch*3+2].envelope[ LEFT] = ::envelope[mode][step] & mask;
if (saa->env_reverse_right[ch] & 0x01) {
saa->channels[ch*3+0].envelope[RIGHT] =
saa->channels[ch*3+1].envelope[RIGHT] =
saa->channels[ch*3+2].envelope[RIGHT] = (15 - ::envelope[mode][step]) & mask;
} else {
saa->channels[ch*3+0].envelope[RIGHT] =
saa->channels[ch*3+1].envelope[RIGHT] =
saa->channels[ch*3+2].envelope[RIGHT] = ::envelope[mode][step] & mask;
}
} else {
/* envelope mode off, set all envelope factors to 16 */
saa->channels[ch*3+0].envelope[ LEFT] =
saa->channels[ch*3+1].envelope[ LEFT] =
saa->channels[ch*3+2].envelope[ LEFT] =
saa->channels[ch*3+0].envelope[RIGHT] =
saa->channels[ch*3+1].envelope[RIGHT] =
saa->channels[ch*3+2].envelope[RIGHT] = 16;
}
}
void DOSBoxCMS::update(int chip, int16 *buffer, int length) {
struct SAA1099 *saa = &_saa1099[chip];
int32 rate;
int j, ch;
if (chip == 0) {
memset(buffer, 0, sizeof(int16)*length);
}
/* if the channels are disabled we're done */
if (!saa->all_ch_enable) {
return;
}
for (ch = 0; ch < 2; ch++) {
switch (saa->noise_params[ch]) {
case 0: saa->noise[ch].freq = (MASTER_CLOCK * 2) / 256; break;
case 1: saa->noise[ch].freq = (MASTER_CLOCK * 2) / 512; break;
case 2: saa->noise[ch].freq = (MASTER_CLOCK * 2) / 1024; break;
case 3: saa->noise[ch].freq = saa->channels[ch * 3].freq; break;
default: break;
}
}
rate = getRate() * FRAC_ONE_CMS;
/* fill all data needed */
for (j = 0; j < length / 2; ++j) {
int output_l = 0, output_r = 0;
/* for each channel */
for (ch = 0; ch < 6; ch++) {
if (saa->channels[ch].freq == 0)
saa->channels[ch].freq = (((2 * MASTER_CLOCK) / 512) << saa->channels[ch].octave) /
(511 - saa->channels[ch].frequency);
/* check the actual position in the square wave */
saa->channels[ch].counter -= saa->channels[ch].freq;
while (saa->channels[ch].counter < 0) {
/* calculate new frequency now after the half wave is updated */
saa->channels[ch].freq = (((2 * MASTER_CLOCK) / 512) << saa->channels[ch].octave) /
(511 - saa->channels[ch].frequency);
saa->channels[ch].counter += rate;
saa->channels[ch].level ^= 1;
/* eventually clock the envelope counters */
if (ch == 1 && saa->env_clock[0] == 0)
envelope(chip, 0);
if (ch == 4 && saa->env_clock[1] == 0)
envelope(chip, 1);
}
/* if the noise is enabled */
if (saa->channels[ch].noise_enable) {
/* if the noise level is high (noise 0: chan 0-2, noise 1: chan 3-5) */
if (saa->noise[ch/3].level & 1) {
/* subtract to avoid overflows, also use only half amplitude */
output_l -= saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16 / 2;
output_r -= saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16 / 2;
}
}
/* if the square wave is enabled */
if (saa->channels[ch].freq_enable) {
/* if the channel level is high */
if (saa->channels[ch].level & 1) {
output_l += saa->channels[ch].amplitude[ LEFT] * saa->channels[ch].envelope[ LEFT] / 16;
output_r += saa->channels[ch].amplitude[RIGHT] * saa->channels[ch].envelope[RIGHT] / 16;
}
}
}
for (ch = 0; ch < 2; ch++) {
/* check the actual position in noise generator */
saa->noise[ch].counter -= saa->noise[ch].freq;
while (saa->noise[ch].counter < 0) {
saa->noise[ch].counter += rate;
if (((saa->noise[ch].level & 0x4000) == 0) == ((saa->noise[ch].level & 0x0040) == 0) )
saa->noise[ch].level = (saa->noise[ch].level << 1) | 1;
else
saa->noise[ch].level <<= 1;
}
}
/* write sound data to the buffer */
buffer[j*2+0] = CLIP<int>(buffer[j*2+0] + output_l / 6, -32768, 32767);
buffer[j*2+1] = CLIP<int>(buffer[j*2+1] + output_r / 6, -32768, 32767);
}
}
void DOSBoxCMS::portWriteIntern(int chip, int offset, int data) {
SAA1099 *saa = &_saa1099[chip];
if(offset == 1) {
// address port
saa->selected_reg = data & 0x1f;
if (saa->selected_reg == 0x18 || saa->selected_reg == 0x19) {
/* clock the envelope channels */
if (saa->env_clock[0])
envelope(chip,0);
if (saa->env_clock[1])
envelope(chip,1);
}
return;
}
int reg = saa->selected_reg;
int ch;
switch (reg) {
/* channel i amplitude */
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
ch = reg & 7;
saa->channels[ch].amplitude[LEFT] = amplitude_lookup[data & 0x0f];
saa->channels[ch].amplitude[RIGHT] = amplitude_lookup[(data >> 4) & 0x0f];
break;
/* channel i frequency */
case 0x08:
case 0x09:
case 0x0a:
case 0x0b:
case 0x0c:
case 0x0d:
ch = reg & 7;
saa->channels[ch].frequency = data & 0xff;
break;
/* channel i octave */
case 0x10:
case 0x11:
case 0x12:
ch = (reg - 0x10) << 1;
saa->channels[ch + 0].octave = data & 0x07;
saa->channels[ch + 1].octave = (data >> 4) & 0x07;
break;
/* channel i frequency enable */
case 0x14:
saa->channels[0].freq_enable = data & 0x01;
saa->channels[1].freq_enable = data & 0x02;
saa->channels[2].freq_enable = data & 0x04;
saa->channels[3].freq_enable = data & 0x08;
saa->channels[4].freq_enable = data & 0x10;
saa->channels[5].freq_enable = data & 0x20;
break;
/* channel i noise enable */
case 0x15:
saa->channels[0].noise_enable = data & 0x01;
saa->channels[1].noise_enable = data & 0x02;
saa->channels[2].noise_enable = data & 0x04;
saa->channels[3].noise_enable = data & 0x08;
saa->channels[4].noise_enable = data & 0x10;
saa->channels[5].noise_enable = data & 0x20;
break;
/* noise generators parameters */
case 0x16:
saa->noise_params[0] = data & 0x03;
saa->noise_params[1] = (data >> 4) & 0x03;
break;
/* envelope generators parameters */
case 0x18:
case 0x19:
ch = reg - 0x18;
saa->env_reverse_right[ch] = data & 0x01;
saa->env_mode[ch] = (data >> 1) & 0x07;
saa->env_bits[ch] = data & 0x10;
saa->env_clock[ch] = data & 0x20;
saa->env_enable[ch] = data & 0x80;
/* reset the envelope */
saa->env_step[ch] = 0;
break;
/* channels enable & reset generators */
case 0x1c:
saa->all_ch_enable = data & 0x01;
saa->sync_state = data & 0x02;
if (data & 0x02) {
int i;
/* Synch & Reset generators */
for (i = 0; i < 6; i++) {
saa->channels[i].level = 0;
saa->channels[i].counter = 0;
}
}
break;
default:
// The CMS allows all registers to be written, so we just output some debug
// message here
debug(5, "CMS Unknown write to reg %x with %x",reg, data);
}
}
class CMSMusicPlugin : public NullMusicPlugin {
public:
const char *getName() const override {
return _s("Creative Music System emulator");
}
const char *getId() const override {
return "cms";
}
MusicDevices getDevices() const override;
};
MusicDevices CMSMusicPlugin::getDevices() const {
MusicDevices devices;
devices.push_back(MusicDevice(this, "", MT_CMS));
return devices;
}
//#if PLUGIN_ENABLED_DYNAMIC(CMS)
//REGISTER_PLUGIN_DYNAMIC(CMS, PLUGIN_TYPE_MUSIC, CMSMusicPlugin);
//#else
REGISTER_PLUGIN_STATIC(CMS, PLUGIN_TYPE_MUSIC, CMSMusicPlugin);
//#endif
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