apps/codecs/mod.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * MOD Codec for rockbox
  11  *
  12  * Written from scratch by Rainer Sinsch
  13  *         exclusivly for Rockbox in February 2008
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  21  * KIND, either express or implied.
  22  *
  23  ****************************************************************************/
  24
  25  /**************
  26   * This version supports large files directly from internal memory management.
  27   * There is a drawback however: It may happen that a song is not completely
  28   * loaded when the internal rockbox-ringbuffer (approx. 28MB) is filled up
  29   * As a workaround make sure you don't have directories with mods larger
  30   * than a total of 28MB
  31   *************/
  32
  33 #include "debug.h"
  34 #include "codeclib.h"
  35 #include <inttypes.h>
  36
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <stdlib.h>
  40 #include <ctype.h>
  41
  42
  43 CODEC_HEADER
  44
  45 #define CHUNK_SIZE (1024*2)
  46
  47
  48 /* This codec supports MOD Files:
  49  *
  50  */
  51
  52 static int32_t samples[CHUNK_SIZE] IBSS_ATTR;   /* The sample buffer */
  53
  54 /* Instrument Data */
  55 struct s_instrument {
  56     /* Sample name / description */
  57     /*char description[22];*/
  58
  59     /* Sample length in bytes */
  60     unsigned short length;
  61
  62     /* Sample finetuning (-8 - +7) */
  63     signed char finetune;
  64
  65     /* Sample volume (0 - 64) */
  66     signed char volume;
  67
  68     /* Sample Repeat Position */
  69     unsigned short repeatoffset;
  70
  71     /* Sample Repeat Length  */
  72     unsigned short repeatlength;
  73
  74     /* Offset to sample data */
  75     unsigned int sampledataoffset;
  76 };
  77
  78 /* Song Data */
  79 struct s_song {
  80     /* Song name / title description */
  81     /*char szTitle[20];*/
  82
  83     /* No. of channels in song */
  84     unsigned char noofchannels;
  85
  86     /* No. of instruments used (either 15 or 31) */
  87     unsigned char noofinstruments;
  88
  89     /* How many patterns are beeing played? */
  90     unsigned char songlength;
  91
  92     /* Where to jump after the song end? */
  93     unsigned char songendjumpposition;
  94
  95     /* Pointer to the Pattern Order Table */
  96     unsigned char *patternordertable;
  97
  98     /* Pointer to the pattern data  */
  99     void *patterndata;
 100
 101     /* Pointer to the sample buffer */
 102     signed char *sampledata;
 103
 104     /* Instrument data  */
 105     struct s_instrument instrument[31];
 106 };
 107
 108 struct s_modchannel {
 109     /* Current Volume */
 110     signed char volume;
 111
 112     /* Current Offset to period in PeriodTable of notebeeing played
 113        (can be temporarily negative) */
 114     short periodtableoffset;
 115
 116     /* Current Period beeing played */
 117     short period;
 118
 119     /* Current effect */
 120     unsigned char effect;
 121
 122     /* Current parameters of effect */
 123     unsigned char effectparameter;
 124
 125     /* Current Instrument beeing played */
 126     unsigned char instrument;
 127
 128     /* Current Vibrato Speed */
 129     unsigned char vibratospeed;
 130
 131     /* Current Vibrato Depth */
 132     unsigned char vibratodepth;
 133
 134     /* Current Position for Vibrato in SinTable */
 135     unsigned char vibratosinpos;
 136
 137     /* Current Tremolo Speed */
 138     unsigned char tremolospeed;
 139
 140     /* Current Tremolo Depth */
 141     unsigned char tremolodepth;
 142
 143     /* Current Position for Tremolo in SinTable */
 144     unsigned char tremolosinpos;
 145
 146     /* Current Speed of Effect "Slide Note up" */
 147     unsigned char slideupspeed;
 148
 149     /* Current Speed of Effect "Slide Note down" */
 150     unsigned char slidedownspeed;
 151
 152     /* Current Speed of the "Slide to Note" effect */
 153     unsigned char slidetonotespeed;
 154
 155     /* Current Period of the "Slide to Note" effect */
 156     unsigned short slidetonoteperiod;
 157 };
 158
 159 struct s_modplayer {
 160     /* Ticks per Line */
 161     unsigned char ticksperline;
 162
 163     /* Beats per Minute */
 164     unsigned char bpm;
 165
 166     /* Position of the Song in the Pattern Table (0-127) */
 167     unsigned char patterntableposition;
 168
 169     /* Current Line (may be temporarily < 0) */
 170     signed char currentline;
 171
 172     /* Current Tick */
 173     signed char currenttick;
 174
 175     /* How many samples are required to calculate for each tick? */
 176     unsigned int samplespertick;
 177
 178     /* Information about the channels */
 179     struct s_modchannel modchannel[8];
 180
 181     /* The Amiga Period Table
 182        (+1 because we use index 0 for period 0 = no new note) */
 183     unsigned short periodtable[37*8+1];
 184
 185     /* The sinus table [-255,255] */
 186     signed short sintable[0x40];
 187
 188     /* Is the glissando effect enabled? */
 189     bool glissandoenabled;
 190
 191     /* Is the Amiga Filter enabled? */
 192     bool amigafilterenabled;
 193
 194     /* The pattern-line where the loop is carried out (set with e6 command) */
 195     unsigned char loopstartline;
 196
 197     /* Number of times to loop */
 198     unsigned char looptimes;
 199 };
 200
 201 struct s_channel {
 202     /* Panning (0 = left, 16 = right) */
 203     unsigned char panning;
 204
 205     /* Sample frequency of the channel */
 206     unsigned short frequency;
 207
 208     /* Position of the sample currently played */
 209     unsigned int samplepos;
 210
 211     /* Fractual Position of the sample currently player */
 212     unsigned int samplefractpos;
 213
 214     /* Loop Sample */
 215     bool loopsample;
 216
 217     /* Loop Position Start */
 218     unsigned int loopstart;
 219
 220     /* Loop Position End */
 221     unsigned int loopend;
 222
 223     /* Is The channel beeing played? */
 224     bool channelactive;
 225
 226     /* The Volume (0..64) */
 227     signed char volume;
 228
 229     /* The last sampledata beeing played (required for interpolation) */
 230     signed short lastsampledata;
 231 };
 232
 233 struct s_mixer {
 234     /* The channels */
 235     struct s_channel channel[32];
 236 };
 237
 238 struct s_song modsong IDATA_ATTR;               /* The Song */
 239 struct s_modplayer modplayer IDATA_ATTR;        /* The Module Player */
 240 struct s_mixer mixer IDATA_ATTR;
 241
 242 const unsigned short mixingrate = 44100;
 243
 244 STATICIRAM void mixer_playsample(int channel, int instrument) ICODE_ATTR;
 245 void mixer_playsample(int channel, int instrument)
 246 {
 247     struct s_channel *p_channel = &mixer.channel[channel];
 248     struct s_instrument *p_instrument = &modsong.instrument[instrument];
 249
 250     p_channel->channelactive = true;
 251     p_channel->samplepos = p_instrument->sampledataoffset;
 252     p_channel->samplefractpos = 0;
 253     p_channel->loopsample = (p_instrument->repeatlength > 2);
 254     if (p_channel->loopsample) {
 255         p_channel->loopstart = p_instrument->repeatoffset +
 256             p_instrument->sampledataoffset;
 257         p_channel->loopend = p_channel->loopstart +
 258             p_instrument->repeatlength;
 259     }
 260     else p_channel->loopend = p_instrument->length +
 261             p_instrument->sampledataoffset;
 262
 263     /* Remember the instrument */
 264     modplayer.modchannel[channel].instrument = instrument;
 265 }
 266
 267 static inline void mixer_stopsample(int channel)
 268 {
 269     mixer.channel[channel].channelactive = false;
 270 }
 271
 272 static inline void mixer_continuesample(int channel)
 273 {
 274     mixer.channel[channel].channelactive = true;
 275 }
 276
 277 static inline void mixer_setvolume(int channel, int volume)
 278 {
 279     mixer.channel[channel].volume = volume;
 280 }
 281
 282 static inline void mixer_setpanning(int channel, int panning)
 283 {
 284     mixer.channel[channel].panning = panning;
 285 }
 286
 287 static inline void mixer_setamigaperiod(int channel, int amigaperiod)
 288 {
 289     /* Just to make sure we don't devide by zero
 290      * amigaperiod shouldn't 0 anyway - if it is the case
 291      * then something terribly went wrong */
 292     if (amigaperiod == 0)
 293         return;
 294
 295     mixer.channel[channel].frequency = 3579546 / amigaperiod;
 296 }
 297
 298 /* Initialize the MOD Player with default values and precalc tables */
 299 STATICIRAM void initmodplayer(void) ICODE_ATTR;
 300 void initmodplayer(void)
 301 {
 302     unsigned int i,c;
 303
 304     /* Calculate Amiga Period Values
 305      * Start with Period 907 (= C-1 with Finetune -8) and work upwards */
 306     double f = 907.0f;
 307     /* Index 0 stands for no note (and therefore no period) */
 308     modplayer.periodtable[0] = 0;
 309     for (i=1;i<297;i++)
 310     {
 311         modplayer.periodtable[i] = (unsigned short) f;
 312         f /= 1.0072464122237039; /* = pow(2.0f, 1.0f/(12.0f*8.0f)); */
 313     }
 314
 315     /*
 316      * This is a more accurate but also time more consuming approach
 317      * to calculate the amiga period table
 318      * Commented out for speed purposes
 319     const int finetuning = 8;
 320     const int octaves = 3;
 321     for (int halftone=0;halftone<=finetuning*octaves*12+7;halftone++)
 322         {
 323             float e = pow(2.0f, halftone/(12.0f*8.0f));
 324             float f = 906.55f/e;
 325             modplayer.periodtable[halfetone+1] = (int)(f+0.5f);
 326         }
 327     */
 328
 329     /* Calculate Protracker Vibrato sine table
 330      * The routine makes use of the Harmonical Oscillator Approach
 331      * for calculating sine tables
 332      * (see http://membres.lycos.fr/amycoders/tutorials/sintables.html)
 333      * The routine presented here calculates a complete sine wave
 334      * with 64 values in range [-255,255]
 335      */
 336     float a, b, d, dd;
 337
 338     d = 0.09817475f; /* = 2*PI/64 */
 339     dd = d*d;
 340     a = 0;
 341     b = d;
 342
 343     for (i=0;i<0x40;i++)
 344     {
 345         modplayer.sintable[i] = (int)(255*a);
 346
 347         a = a+b;
 348         b = b-dd*a;
 349     }
 350
 351     /* Set Default Player Values */
 352     modplayer.currentline = 0;
 353     modplayer.currenttick = 0;
 354     modplayer.patterntableposition = 0;
 355     modplayer.bpm = 125;
 356     modplayer.ticksperline = 6;
 357     modplayer.glissandoenabled = false;         /* Disable glissando */
 358     modplayer.amigafilterenabled = false;       /* Disable the Amiga Filter */
 359
 360     /* Default Panning Values */
 361     int panningvalues[8] = {4,12,12,4,4,12,12,4};
 362     for (c=0;c<8;c++)
 363     {
 364         /* Set Default Panning */
 365         mixer_setpanning(c, panningvalues[c]);
 366         /* Reset channels in the MOD Player */
 367         memset(&modplayer.modchannel[c], 0, sizeof(struct s_modchannel));
 368         /* Don't play anything */
 369         mixer.channel[c].channelactive = false;
 370     }
 371
 372 }
 373
 374 /* Load the MOD File from memory */
 375 STATICIRAM bool loadmod(void *modfile) ICODE_ATTR;
 376 bool loadmod(void *modfile)
 377 {
 378     int i;
 379     unsigned char *periodsconverted;
 380
 381     /* We don't support PowerPacker 2.0 Files */
 382     if (memcmp((char*) modfile, "PP20", 4) == 0) return false;
 383
 384     /* Get the File Format Tag */
 385     char *fileformattag = (char*)modfile + 1080;
 386
 387     /* Find out how many channels and instruments are used */
 388     if (memcmp(fileformattag, "2CHN", 4) == 0)
 389         {modsong.noofchannels = 2; modsong.noofinstruments = 31;}
 390     else if (memcmp(fileformattag, "M.K.", 4) == 0)
 391         {modsong.noofchannels = 4; modsong.noofinstruments = 31;}
 392     else if (memcmp(fileformattag, "M!K!", 4) == 0)
 393         {modsong.noofchannels = 4; modsong.noofinstruments = 31;}
 394     else if (memcmp(fileformattag, "4CHN", 4) == 0)
 395         {modsong.noofchannels = 4; modsong.noofinstruments = 31;}
 396     else if (memcmp(fileformattag, "FLT4", 4) == 0)
 397         {modsong.noofchannels = 4; modsong.noofinstruments = 31;}
 398     else if (memcmp(fileformattag, "6CHN", 4) == 0)
 399         {modsong.noofchannels = 6; modsong.noofinstruments = 31;}
 400     else if (memcmp(fileformattag, "8CHN", 4) == 0)
 401         {modsong.noofchannels = 8; modsong.noofinstruments = 31;}
 402     else if (memcmp(fileformattag, "OKTA", 4) == 0)
 403         {modsong.noofchannels = 8; modsong.noofinstruments = 31;}
 404     else if (memcmp(fileformattag, "CD81", 4) == 0)
 405         {modsong.noofchannels = 8; modsong.noofinstruments = 31;}
 406     else {
 407         /* The file has no format tag, so most likely soundtracker */
 408         modsong.noofchannels = 4;
 409         modsong.noofinstruments = 15;
 410     }
 411
 412     /* Get the Song title
 413      * Skipped here
 414      * strncpy(modsong.szTitle, (char*)pMODFile, 20); */
 415
 416     /* Get the Instrument information */
 417     for (i=0;i<modsong.noofinstruments;i++)
 418     {
 419         struct s_instrument *instrument = &modsong.instrument[i];
 420         unsigned char *p = (unsigned char *)modfile + 20 + i*30;
 421
 422         /*strncpy(instrument->description, (char*)p, 22); */
 423         p += 22;
 424         instrument->length = (((p[0])<<8) + p[1]) << 1; p+=2;
 425         instrument->finetune = *p++ & 0x0f;
 426         /* Treat finetuning as signed nibble */
 427         if (instrument->finetune > 7) instrument->finetune -= 16;
 428         instrument->volume = *p++;
 429         instrument->repeatoffset = (((p[0])<<8) + p[1]) << 1; p+= 2;
 430         instrument->repeatlength = (((p[0])<<8) + p[1]) << 1;
 431     }
 432
 433     /* Get the pattern information */
 434     unsigned char *p = (unsigned char *)modfile + 20 +
 435         modsong.noofinstruments*30;
 436     modsong.songlength = *p++;
 437     modsong.songendjumpposition = *p++;
 438     modsong.patternordertable = p;
 439
 440     /* Find out how many patterns are used within this song */
 441     int maxpatterns = 0;
 442     for (i=0;i<128;i++)
 443         if (modsong.patternordertable[i] > maxpatterns)
 444             maxpatterns = modsong.patternordertable[i];
 445     maxpatterns++;
 446
 447     /* use 'restartposition' (historically set to 127) which is not used here
 448        as a marker that periods have already been converted */
 449
 450     periodsconverted = (char*)modfile + 20 + modsong.noofinstruments*30 + 1;
 451
 452     /* Get the pattern data; ST doesn't have fileformattag, so 4 bytes less */
 453     modsong.patterndata = periodsconverted +
 454                           (modsong.noofinstruments==15 ? 129 : 133);
 455
 456     /* Convert the period values in the mod file to offsets
 457      * in our periodtable (but only, if we haven't done this yet) */
 458     p = (unsigned char *) modsong.patterndata;
 459     if (*periodsconverted != 0xfe)
 460     {
 461         int note, note2, channel;
 462         for (note=0;note<maxpatterns*64;note++)
 463             for (channel=0;channel<modsong.noofchannels;channel++)
 464             {
 465                 int period = ((p[0] & 0x0f) << 8) | p[1];
 466                 int periodoffset = 0;
 467
 468                 /* Find the offset of the current period */
 469                 for (note2 = 1; note2 < 12*3+1; note2++)
 470                     if (abs(modplayer.periodtable[note2*8+1]-period) < 4)
 471                     {
 472                         periodoffset = note2*8+1;
 473                         break;
 474                     }
 475                 /* Write back the period offset */
 476                 p[0] = (periodoffset >> 8) | (p[0] & 0xf0);
 477                 p[1] = periodoffset & 0xff;
 478                 p += 4;
 479             }
 480         /* Remember that we already converted the periods,
 481          * in case the file gets reloaded by rewinding
 482          * with 0xfe (arbitary magic value > 127) */
 483         *periodsconverted = 0xfe;
 484     }
 485
 486     /* Get the samples
 487      * Calculation: The Samples come after the pattern data
 488      * We know that there are nMaxPatterns and each pattern requires
 489      * 4 bytes per note and per channel.
 490      * And of course there are always lines in each channel */
 491     modsong.sampledata = (signed char*) modsong.patterndata +
 492                           maxpatterns*4*modsong.noofchannels*64;
 493     int sampledataoffset = 0;
 494     for (i=0;i<modsong.noofinstruments;i++)
 495     {
 496         modsong.instrument[i].sampledataoffset = sampledataoffset;
 497         sampledataoffset += modsong.instrument[i].length;
 498     }
 499
 500     return true;
 501 }
 502
 503 /* Apply vibrato to channel */
 504 STATICIRAM void vibrate(int channel) ICODE_ATTR;
 505 void vibrate(int channel)
 506 {
 507     struct s_modchannel *p_modchannel = &modplayer.modchannel[channel];
 508
 509     /* Apply Vibrato
 510      * >> 7 is used in the original protracker source code */
 511     mixer_setamigaperiod(channel, p_modchannel->period+
 512         ((p_modchannel->vibratodepth *
 513         modplayer.sintable[p_modchannel->vibratosinpos])>>7));
 514
 515     /* Foward in Sine Table */
 516     p_modchannel->vibratosinpos += p_modchannel->vibratospeed;
 517     p_modchannel->vibratosinpos &= 0x3f;
 518 }
 519
 520 /* Apply tremolo to channel
 521  * (same as vibrato, but only apply on volume instead of pitch) */
 522 STATICIRAM void tremolo(int channel) ICODE_ATTR;
 523 void tremolo(int channel)
 524 {
 525     struct s_modchannel *p_modchannel = &modplayer.modchannel[channel];
 526
 527     /* Apply Tremolo
 528      * >> 6 is used in the original protracker source code */
 529     int volume = (p_modchannel->volume *
 530         modplayer.sintable[p_modchannel->tremolosinpos])>>6;
 531     if (volume > 64) volume = 64;
 532     else if (volume < 0) volume = 0;
 533     mixer_setvolume(channel, volume);
 534
 535     /* Foward in Sine Table */
 536     p_modchannel->tremolosinpos += p_modchannel->tremolosinpos;
 537     p_modchannel->tremolosinpos &= 0x3f;
 538 }
 539
 540 /* Apply Slide to Note effect to channel */
 541 STATICIRAM void slidetonote(int channel) ICODE_ATTR;
 542 void slidetonote(int channel)
 543 {
 544     struct s_modchannel *p_modchannel = &modplayer.modchannel[channel];
 545
 546     /* If there hasn't been any slide-to note set up, then return */
 547     if (p_modchannel->slidetonoteperiod == 0) return;
 548
 549     /* Slide note up */
 550     if (p_modchannel->slidetonoteperiod > p_modchannel->period)
 551     {
 552         p_modchannel->period += p_modchannel->slidetonotespeed;
 553         if (p_modchannel->period > p_modchannel->slidetonoteperiod)
 554             p_modchannel->period = p_modchannel->slidetonoteperiod;
 555     }
 556     /* Slide note down */
 557     else if (p_modchannel->slidetonoteperiod < p_modchannel->period)
 558     {
 559         p_modchannel->period -= p_modchannel->slidetonotespeed;
 560         if (p_modchannel->period < p_modchannel->slidetonoteperiod)
 561             p_modchannel->period = p_modchannel->slidetonoteperiod;
 562     }
 563     mixer_setamigaperiod(channel, p_modchannel->period);
 564 }
 565
 566 /* Apply Slide to Note effect on channel,
 567  * but this time with glissando enabled */
 568 STATICIRAM void slidetonoteglissando(int channel) ICODE_ATTR;
 569 void slidetonoteglissando(int channel)
 570 {
 571     struct s_modchannel *p_modchannel = &modplayer.modchannel[channel];
 572
 573     /* Slide note up */
 574     if (p_modchannel->slidetonoteperiod > p_modchannel->period)
 575     {
 576         p_modchannel->period =
 577             modplayer.periodtable[p_modchannel->periodtableoffset+=8];
 578         if (p_modchannel->period > p_modchannel->slidetonoteperiod)
 579             p_modchannel->period = p_modchannel->slidetonoteperiod;
 580     }
 581     /* Slide note down */
 582     else
 583     {
 584         p_modchannel->period =
 585             modplayer.periodtable[p_modchannel->periodtableoffset-=8];
 586         if (p_modchannel->period < p_modchannel->slidetonoteperiod)
 587             p_modchannel->period = p_modchannel->slidetonoteperiod;
 588     }
 589     mixer_setamigaperiod(channel, p_modchannel->period);
 590 }
 591
 592 /* Apply Volume Slide */
 593 STATICIRAM void volumeslide(int channel, int effectx, int effecty) ICODE_ATTR;
 594 void volumeslide(int channel, int effectx, int effecty)
 595 {
 596     struct s_modchannel *p_modchannel = &modplayer.modchannel[channel];
 597
 598     /* If both X and Y Parameters are non-zero, then the y value is ignored */
 599     if (effectx > 0) {
 600         p_modchannel->volume += effectx;
 601         if (p_modchannel->volume > 64) p_modchannel->volume = 64;
 602     }
 603     else {
 604         p_modchannel->volume -= effecty;
 605         if (p_modchannel->volume < 0) p_modchannel->volume = 0;
 606     }
 607
 608     mixer_setvolume(channel, p_modchannel->volume);
 609 }
 610
 611 /* Play the current line (at tick 0) */
 612 STATICIRAM void playline(int pattern, int line) ICODE_ATTR;
 613 void playline(int pattern, int line)
 614 {
 615     int c;
 616
 617     /* Get pointer to the current pattern */
 618     unsigned char *p_line = (unsigned char*)modsong.patterndata;
 619     p_line += pattern*64*4*modsong.noofchannels;
 620     p_line += line*4*modsong.noofchannels;
 621
 622     /* Only allow one Patternbreak Commando per Line */
 623     bool patternbreakdone = false;
 624
 625     for (c=0;c<modsong.noofchannels;c++)
 626     {
 627         struct s_modchannel *p_modchannel = &modplayer.modchannel[c];
 628         unsigned char *p_note = p_line + c*4;
 629         unsigned char samplenumber = (p_note[0] & 0xf0) | (p_note[2] >> 4);
 630         short periodtableoffset = ((p_note[0] & 0x0f) << 8) | p_note[1];
 631
 632         p_modchannel->effect = p_note[2] & 0x0f;
 633         p_modchannel->effectparameter = p_note[3];
 634
 635         /* Remember Instrument and set Volume if new Instrument triggered */
 636         if (samplenumber > 0)
 637         {
 638             /* And trigger new sample, if new instrument was set */
 639             if (samplenumber-1 != p_modchannel->instrument)
 640             {
 641                 /* Advance the new sample to the same offset
 642                  * the old sample was beeing played */
 643                 int oldsampleoffset = mixer.channel[c].samplepos -
 644                     modsong.instrument[
 645                     p_modchannel->instrument].sampledataoffset;
 646                 mixer_playsample(c, samplenumber-1);
 647                 mixer.channel[c].samplepos += oldsampleoffset;
 648             }
 649
 650             /* Remember last played instrument on channel */
 651             p_modchannel->instrument = samplenumber-1;
 652
 653             /* Set Volume to standard instrument volume,
 654              * if not overwritten by volume effect */
 655             if (p_modchannel->effect != 0x0c)
 656             {
 657                 p_modchannel->volume = modsong.instrument[
 658                     p_modchannel->instrument].volume;
 659                 mixer_setvolume(c, p_modchannel->volume);
 660             }
 661         }
 662         /* Trigger new sample if note available */
 663         if (periodtableoffset > 0)
 664         {
 665             /* Restart instrument only when new sample triggered */
 666             if (samplenumber != 0)
 667                 mixer_playsample(c, (samplenumber > 0) ?
 668                     samplenumber-1 : p_modchannel->instrument);
 669
 670             /* Set the new amiga period
 671              * (but only, if there is no slide to note effect) */
 672             if ((p_modchannel->effect != 0x3) &&
 673                 (p_modchannel->effect != 0x5))
 674             {
 675                 /* Apply finetuning to sample */
 676                 p_modchannel->periodtableoffset = periodtableoffset +
 677                     modsong.instrument[p_modchannel->instrument].finetune;
 678                 p_modchannel->period = modplayer.periodtable[
 679                     p_modchannel->periodtableoffset];
 680                 mixer_setamigaperiod(c, p_modchannel->period);
 681                 /* When a new note is played without slide to note setup,
 682                  * then disable slide to note */
 683                 modplayer.modchannel[c].slidetonoteperiod =
 684                     p_modchannel->period;
 685             }
 686         }
 687         int effectx = p_modchannel->effectparameter>>4;
 688         int effecty = p_modchannel->effectparameter&0x0f;
 689
 690         switch (p_modchannel->effect)
 691         {
 692             /* Effect 0: Arpeggio */
 693             case 0x00:
 694                 /* Set the base period on tick 0 */
 695                 if (p_modchannel->effectparameter > 0)
 696                     mixer_setamigaperiod(c,
 697                         modplayer.periodtable[
 698                             p_modchannel->periodtableoffset]);
 699                 break;
 700             /* Slide up (Portamento up) */
 701             case 0x01:
 702                 if (p_modchannel->effectparameter > 0)
 703                     p_modchannel->slideupspeed =
 704                         p_modchannel->effectparameter;
 705                 break;
 706
 707             /* Slide down (Portamento down) */
 708             case 0x02:
 709                 if (p_modchannel->effectparameter > 0)
 710                     p_modchannel->slidedownspeed =
 711                         p_modchannel->effectparameter;
 712                 break;
 713
 714             /* Slide to Note */
 715             case 0x03:
 716                 if (p_modchannel->effectparameter > 0)
 717                     p_modchannel->slidetonotespeed =
 718                         p_modchannel->effectparameter;
 719                 /* Get the slide to note directly from the pattern buffer */
 720                 if (periodtableoffset > 0)
 721                     p_modchannel->slidetonoteperiod =
 722                         modplayer.periodtable[periodtableoffset +
 723                         modsong.instrument[
 724                         p_modchannel->instrument].finetune];
 725                 /* If glissando is enabled apply the effect directly here */
 726                 if (modplayer.glissandoenabled)
 727                     slidetonoteglissando(c);
 728                 break;
 729
 730             /* Set Vibrato */
 731             case 0x04:
 732                 if (effectx > 0) p_modchannel->vibratospeed = effectx;
 733                 if (effecty > 0) p_modchannel->vibratodepth = effecty;
 734                 break;
 735
 736             /* Effect 0x06: Slide to note */
 737             case 0x05:
 738                 /* Get the slide to note directly from the pattern buffer */
 739                 if (periodtableoffset > 0)
 740                     p_modchannel->slidetonoteperiod =
 741                         modplayer.periodtable[periodtableoffset +
 742                             modsong.instrument[
 743                             p_modchannel->instrument].finetune];
 744                 break;
 745
 746             /* Effect 0x06 is "Continue Effects" */
 747             /* It is not processed on tick 0 */
 748             case 0x06:
 749                 break;
 750
 751             /* Set Tremolo */
 752             case 0x07:
 753                 if (effectx > 0) p_modchannel->tremolodepth = effectx;
 754                 if (effecty > 0) p_modchannel->tremolospeed = effecty;
 755                 break;
 756
 757             /* Set fine panning */
 758             case 0x08:
 759                 /* Internal panning goes from 0..15
 760                  * Scale the fine panning value to that range */
 761                 mixer.channel[c].panning = p_modchannel->effectparameter>>4;
 762                 break;
 763
 764             /* Set Sample Offset */
 765             case 0x09:
 766                 {
 767                     struct s_instrument *p_instrument =
 768                         &modsong.instrument[p_modchannel->instrument];
 769                     int sampleoffset = p_instrument->sampledataoffset;
 770                     if (sampleoffset > p_instrument->length)
 771                         sampleoffset = p_instrument->length;
 772                     /* Forward the new offset to the mixer */
 773                     mixer.channel[c].samplepos =
 774                         p_instrument->sampledataoffset +
 775                         (p_modchannel->effectparameter<<8);
 776                     mixer.channel[c].samplefractpos = 0;
 777                 break;
 778                 }
 779
 780             /* Effect 0x0a (Volume slide) is not processed on tick 0 */
 781
 782             /* Position Jump */
 783             case 0x0b:
 784                 modplayer.currentline = -1;
 785                 modplayer.patterntableposition = (effectx<<4)+effecty;
 786                 break;
 787
 788             /* Set Volume */
 789             case 0x0c:
 790                 p_modchannel->volume = p_modchannel->effectparameter;
 791                 mixer_setvolume(c, p_modchannel->volume);
 792                 break;
 793
 794             /* Pattern break */
 795             case 0x0d:
 796                 modplayer.currentline = effectx*10 + effecty - 1;
 797                 if (!patternbreakdone)
 798                 {
 799                     patternbreakdone = true;
 800                     modplayer.patterntableposition++;
 801                 }
 802                 break;
 803
 804             /* Extended Effects */
 805             case 0x0e:
 806                 switch (effectx)
 807                 {
 808                     /* Set Filter */
 809                     case 0x0:
 810                         modplayer.amigafilterenabled = (effecty == 0);
 811                         break;
 812                     /* Fineslide up */
 813                     case 0x1:
 814                         mixer_setamigaperiod(c, p_modchannel->period -=
 815                             effecty);
 816                         if (p_modchannel->period <
 817                             modplayer.periodtable[37*8]) p_modchannel->period = 100;
 818                         /* Find out the new offset in the period table */
 819                         if (p_modchannel->periodtableoffset < 36*8)
 820                             while (modplayer.periodtable[
 821                                 p_modchannel->periodtableoffset+8] >= p_modchannel->period)
 822                                     p_modchannel->periodtableoffset+=8;
 823                         break;
 824                     /* Fineslide down */
 825                     case 0x2:
 826                         mixer_setamigaperiod(c,
 827                             p_modchannel->period += effecty);
 828                         if (p_modchannel->periodtableoffset > 8)
 829                             while (modplayer.periodtable[
 830                                 p_modchannel->periodtableoffset-8]
 831                                 <= p_modchannel->period)
 832                             p_modchannel->periodtableoffset-=8;
 833                         break;
 834                     /* Set glissando on/off */
 835                     case 0x3:
 836                         modplayer.glissandoenabled = (effecty > 0);
 837                         break;
 838                     /* Set Vibrato waveform */
 839                     case 0x4:
 840                         /* Currently not implemented */
 841                         break;
 842                     /* Set Finetune value */
 843                     case 0x5:
 844                         /* Treat as signed nibble */
 845                         if (effecty > 7) effecty -= 16;
 846
 847                         p_modchannel->periodtableoffset +=
 848                             effecty -
 849                                 modsong.instrument[
 850                                 p_modchannel->instrument].finetune;
 851                         p_modchannel->period =
 852                             modplayer.periodtable[
 853                             p_modchannel->periodtableoffset];
 854                         modsong.instrument[
 855                             p_modchannel->instrument].finetune = effecty;
 856                         break;
 857                     /* Pattern loop */
 858                     case 0x6:
 859                         if (effecty == 0)
 860                             modplayer.loopstartline = line-1;
 861                         else
 862                         {
 863                             if (modplayer.looptimes == 0)
 864                             {
 865                                 modplayer.currentline =
 866                                     modplayer.loopstartline;
 867                                 modplayer.looptimes = effecty;
 868                             }
 869                             else modplayer.looptimes--;
 870                             if (modplayer.looptimes > 0)
 871                                 modplayer.currentline =
 872                                     modplayer.loopstartline;
 873                         }
 874                         break;
 875                     /* Set Tremolo waveform */
 876                     case 0x7:
 877                         /* Not yet implemented */
 878                         break;
 879                     /* Enhanced Effect 8 is not used */
 880                     case 0x8:
 881                         break;
 882                     /* Retrigger sample */
 883                     case 0x9:
 884                         /* Only processed on subsequent ticks */
 885                         break;
 886                     /* Fine volume slide up */
 887                     case 0xa:
 888                         p_modchannel->volume += effecty;
 889                         if (p_modchannel->volume > 64)
 890                             p_modchannel->volume = 64;
 891                         mixer_setvolume(c, p_modchannel->volume);
 892                         break;
 893                     /* Fine volume slide down */
 894                     case 0xb:
 895                         p_modchannel->volume -= effecty;
 896                         if (p_modchannel->volume < 0)
 897                             p_modchannel->volume = 0;
 898                         mixer_setvolume(c, p_modchannel->volume);
 899                         break;
 900                     /* Cut sample */
 901                     case 0xc:
 902                         /* Continue sample */
 903                         mixer_continuesample(c);
 904                         break;
 905                     /* Note delay (Usage: $ED + ticks to delay note.) */
 906                     case 0xd:
 907                         /* We stop the sample here on tick 0
 908                          * and restart it later in the effect */
 909                         if (effecty > 0)
 910                             mixer.channel[c].channelactive = false;
 911                         break;
 912                 }
 913                 break;
 914
 915             /* Set Speed */
 916             case 0x0f:
 917                 if (p_modchannel->effectparameter < 32)
 918                     modplayer.ticksperline = p_modchannel->effectparameter;
 919                 else
 920                     modplayer.bpm = p_modchannel->effectparameter;
 921                 break;
 922         }
 923     }
 924 }
 925
 926 /* Play the current effect of the note (ticks 1..speed) */
 927 STATICIRAM void playeffect(int currenttick) ICODE_ATTR;
 928 void playeffect(int currenttick)
 929 {
 930     int c;
 931
 932     for (c=0;c<modsong.noofchannels;c++)
 933     {
 934         struct s_modchannel *p_modchannel = &modplayer.modchannel[c];
 935
 936         /* If there is no note active then there are no effects to play */
 937         if (p_modchannel->period == 0) continue;
 938
 939         unsigned char effectx = p_modchannel->effectparameter>>4;
 940         unsigned char effecty = p_modchannel->effectparameter&0x0f;
 941
 942         switch (p_modchannel->effect)
 943         {
 944             /* Effect 0: Arpeggio */
 945             case 0x00:
 946                 if (p_modchannel->effectparameter > 0)
 947                 {
 948                     unsigned short newperiodtableoffset;
 949                     switch (currenttick % 3)
 950                     {
 951                         case 0:
 952                             mixer_setamigaperiod(c,
 953                                 modplayer.periodtable[
 954                                     p_modchannel->periodtableoffset]);
 955                             break;
 956                         case 1:
 957                             newperiodtableoffset =
 958                                 p_modchannel->periodtableoffset+(effectx<<3);
 959                             if (newperiodtableoffset < 37*8)
 960                                 mixer_setamigaperiod(c,
 961                                     modplayer.periodtable[
 962                                         newperiodtableoffset]);
 963                             break;
 964                         case 2:
 965                             newperiodtableoffset =
 966                                 p_modchannel->periodtableoffset+(effecty<<3);
 967                             if (newperiodtableoffset < 37*8)
 968                                 mixer_setamigaperiod(c,
 969                                     modplayer.periodtable[
 970                                         newperiodtableoffset]);
 971                             break;
 972                     }
 973                 }
 974                 break;
 975
 976             /* Effect 1: Slide Up */
 977             case 0x01:
 978                 mixer_setamigaperiod(c,
 979                     p_modchannel->period -= p_modchannel->slideupspeed);
 980                 /* Find out the new offset in the period table */
 981                 if (p_modchannel->periodtableoffset <= 37*8)
 982                     while (modplayer.periodtable[
 983                         p_modchannel->periodtableoffset] >
 984                         p_modchannel->period)
 985                     {
 986                         p_modchannel->periodtableoffset++;
 987                         /* Make sure we don't go out of range */
 988                         if (p_modchannel->periodtableoffset > 37*8)
 989                         {
 990                             p_modchannel->periodtableoffset = 37*8;
 991                             break;
 992                         }
 993                     }
 994                 break;
 995
 996             /* Effect 2: Slide Down */
 997             case 0x02:
 998                 mixer_setamigaperiod(c, p_modchannel->period +=
 999                     p_modchannel->slidedownspeed);
1000                 /* Find out the new offset in the period table */
1001                 if (p_modchannel->periodtableoffset > 8)
1002                     while (modplayer.periodtable[
1003                         p_modchannel->periodtableoffset] <
1004                         p_modchannel->period)
1005                     {
1006                         p_modchannel->periodtableoffset--;
1007                         /* Make sure we don't go out of range */
1008                         if (p_modchannel->periodtableoffset < 1)
1009                         {
1010                             p_modchannel->periodtableoffset = 1;
1011                             break;
1012                         }
1013                     }
1014                 break;
1015
1016             /* Effect 3: Slide to Note */
1017             case 0x03:
1018                 /* Apply smooth sliding, if no glissando is enabled */
1019                 if (modplayer.glissandoenabled == 0)
1020                     slidetonote(c);
1021                 break;
1022
1023             /* Effect 4: Vibrato */
1024             case 0x04:
1025                 vibrate(c);
1026                 break;
1027
1028             /* Effect 5: Continue effect 3:'Slide to note',
1029              *           but also do Volume slide */
1030             case 0x05:
1031                 slidetonote(c);
1032                 volumeslide(c, effectx, effecty);
1033                 break;
1034
1035             /* Effect 6: Continue effect 4:'Vibrato',
1036              *           but also do Volume slide */
1037             case 0x06:
1038                 vibrate(c);
1039                 volumeslide(c, effectx, effecty);
1040                 break;
1041
1042             /* Effect 7: Tremolo */
1043             case 0x07:
1044                 tremolo(c);
1045                 break;
1046
1047             /* Effect 8 (Set fine panning) is only processed at tick 0 */
1048             /* Effect 9 (Set sample offset) is only processed at tick 0 */
1049
1050             /* Effect A: Volume slide */
1051             case 0x0a:
1052                 volumeslide(c, effectx, effecty);
1053                 break;
1054
1055             /* Effect B (Position jump) is only processed at tick 0 */
1056             /* Effect C (Set Volume) is only processed at tick 0 */
1057             /* Effect D (Pattern Preak) is only processed at tick 0 */
1058             /* Effect E (Enhanced Effect) */
1059             case 0x0e:
1060                 switch (effectx)
1061                 {
1062                     /* Retrigger sample ($E9 + Tick to Retrig note at) */
1063                     case 0x9:
1064                         /* Don't device by zero */
1065                         if (effecty == 0) effecty = 1;
1066                         /* Apply retrig */
1067                         if (currenttick % effecty == 0)
1068                             mixer_playsample(c, p_modchannel->instrument);
1069                         break;
1070                     /* Cut note (Usage: $EC + Tick to Cut note at) */
1071                     case 0xc:
1072                         if (currenttick == effecty)
1073                         mixer_stopsample(c);
1074                         break;
1075                     /* Delay note (Usage: $ED + ticks to delay note) */
1076                     case 0xd:
1077                         /* If this is the correct tick,
1078                          * we start playing the sample now */
1079                         if (currenttick == effecty)
1080                             mixer.channel[c].channelactive = true;
1081                         break;
1082
1083                 }
1084                 break;
1085             /* Effect F (Set Speed) is only processed at tick 0 */
1086
1087         }
1088     }
1089 }
1090
1091 static inline int clip(int i)
1092 {
1093     if (i > 32767) return(32767);
1094     else if (i < -32768) return(-32768);
1095     else return(i);
1096 }
1097
1098 STATICIRAM void synthrender(int32_t *renderbuffer, int samplecount) ICODE_ATTR;
1099 void synthrender(int32_t *renderbuffer, int samplecount)
1100 {
1101     /* 125bpm equals to 50Hz (= 0.02s)
1102      * => one tick = mixingrate/50,
1103      * samples passing in one tick:
1104      * mixingrate/(bpm/2.5) = 2.5*mixingrate/bpm */
1105
1106     int32_t *p_left = renderbuffer; /* int in rockbox */
1107     int32_t *p_right = p_left+1;
1108     signed short s;
1109     int qf_distance, qf_distance2;
1110
1111     int i;
1112
1113     int c, left, right;
1114
1115     for (i=0;i<samplecount;i++)
1116     {
1117         /* New Tick? */
1118         if ((modplayer.samplespertick-- <= 0) &&
1119             (modplayer.patterntableposition < 127))
1120         {
1121             if (modplayer.currenttick == 0)
1122                 playline(modsong.patternordertable[
1123                     modplayer.patterntableposition], modplayer.currentline);
1124             else playeffect(modplayer.currenttick);
1125
1126             modplayer.currenttick++;
1127
1128             if (modplayer.currenttick >= modplayer.ticksperline)
1129             {
1130                 modplayer.currentline++;
1131                 modplayer.currenttick = 0;
1132                 if (modplayer.currentline == 64)
1133                 {
1134                     modplayer.patterntableposition++;
1135                     if (modplayer.patterntableposition >= modsong.songlength)
1136                         /* This is for Noise Tracker
1137                          * modplayer.patterntableposition =
1138                          *    modsong.songendjumpposition;
1139                          * More compatible approach is restart from 0 */
1140                         modplayer.patterntableposition=0;
1141                     modplayer.currentline = 0;
1142                 }
1143             }
1144
1145             modplayer.samplespertick = (20*mixingrate/modplayer.bpm)>>3;
1146         }
1147         /* Mix buffers from here
1148          * Walk through all channels */
1149         left=0, right=0;
1150
1151         /* If song has not stopped playing */
1152         if (modplayer.patterntableposition < 127)
1153             /* Loop through all channels */
1154             for (c=0;c<modsong.noofchannels;c++)
1155             {
1156                 /* Only mix the sample,
1157                  * if channel there is something played on the channel */
1158                 if (!mixer.channel[c].channelactive) continue;
1159
1160                 /* Loop the sample, if requested? */
1161                 if (mixer.channel[c].samplepos >= mixer.channel[c].loopend)
1162                 {
1163                     if (mixer.channel[c].loopsample)
1164                         mixer.channel[c].samplepos -=
1165                             (mixer.channel[c].loopend-
1166                             mixer.channel[c].loopstart);
1167                     else mixer.channel[c].channelactive = false;
1168                 }
1169
1170                 /* If the sample has stopped playing don't mix it */
1171                 if (!mixer.channel[c].channelactive) continue;
1172
1173                 /* Get the sample */
1174                 s = (signed short)(modsong.sampledata[
1175                     mixer.channel[c].samplepos]*mixer.channel[c].volume);
1176
1177                 /* Interpolate if the sample-frequency is lower
1178                  * than the mixing rate
1179                  * If you don't want interpolation simply skip this part */
1180                 if (mixer.channel[c].frequency < mixingrate)
1181                 {
1182                     /* Low precision linear interpolation
1183                      * (fast integer based) */
1184                     qf_distance = mixer.channel[c].samplefractpos<<16 /
1185                                     mixingrate;
1186                     qf_distance2 = (1<<16)-qf_distance;
1187                     s = (qf_distance*s + qf_distance2*
1188                         mixer.channel[c].lastsampledata)>>16;
1189                 }
1190
1191                 /* Save the last played sample for interpolation purposes */
1192                 mixer.channel[c].lastsampledata = s;
1193
1194                 /* Pan the sample */
1195                 left += s*(16-mixer.channel[c].panning)>>3;
1196                 right += s*mixer.channel[c].panning>>3;
1197
1198                 /* Advance sample */
1199                 mixer.channel[c].samplefractpos += mixer.channel[c].frequency;
1200                 while (mixer.channel[c].samplefractpos > mixingrate)
1201                 {
1202                     mixer.channel[c].samplefractpos -= mixingrate;
1203                     mixer.channel[c].samplepos++;
1204                 }
1205             }
1206         /* If we have more than 4 channels
1207          * we have to make sure that we apply clipping */
1208         if (modsong.noofchannels > 4) {
1209             *p_left = clip(left)<<13;
1210             *p_right = clip(right)<<13;
1211         }
1212         else {
1213             *p_left = left<<13;
1214             *p_right = right<<13;
1215         }
1216         p_left+=2;
1217         p_right+=2;
1218     }
1219 }
1220
1221
1222 enum codec_status codec_main(void)
1223 {
1224     size_t n;
1225     unsigned char *modfile;
1226     int old_patterntableposition;
1227
1228     int bytesdone;
1229
1230 next_track:
1231     if (codec_init()) {
1232         return CODEC_ERROR;
1233     }
1234
1235     while (!*ci->taginfo_ready && !ci->stop_codec)
1236         ci->sleep(1);
1237
1238     codec_set_replaygain(ci->id3);
1239
1240     /* Load MOD file */
1241     /*
1242      * This is the save way
1243
1244     size_t bytesfree;
1245     unsigned int filesize;
1246
1247     p = modfile;
1248     bytesfree=sizeof(modfile);
1249     while ((n = ci->read_filebuf(p, bytesfree)) > 0) {
1250         p += n;
1251         bytesfree -= n;
1252         if (bytesfree == 0)
1253            return CODEC_ERROR;
1254     }
1255     filesize = p-modfile;
1256
1257     if (filesize == 0)
1258         return CODEC_ERROR;
1259     */
1260
1261     /* Directly use mod in buffer */
1262     ci->seek_buffer(0);
1263     modfile = ci->request_buffer(&n, ci->filesize);
1264     if (!modfile || n < (size_t)ci->filesize) {
1265         return CODEC_ERROR;
1266     }
1267
1268     initmodplayer();
1269     loadmod(modfile);
1270
1271     /* Make use of 44.1khz */
1272     ci->configure(DSP_SET_FREQUENCY, 44100);
1273     /* Sample depth is 28 bit host endian */
1274     ci->configure(DSP_SET_SAMPLE_DEPTH, 28);
1275     /* Stereo output */
1276     ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
1277
1278     /* The main decoder loop */
1279     ci->set_elapsed(0);
1280     bytesdone = 0;
1281     old_patterntableposition = 0;
1282
1283     while (1) {
1284         ci->yield();
1285         if (ci->stop_codec || ci->new_track)
1286             break;
1287
1288         if (ci->seek_time) {
1289             /* New time is ready in ci->seek_time */
1290             modplayer.patterntableposition = ci->seek_time/1000;
1291             modplayer.currentline = 0;
1292             ci->seek_complete();
1293         }
1294
1295         if(old_patterntableposition != modplayer.patterntableposition) {
1296           ci->set_elapsed(modplayer.patterntableposition*1000+500);
1297           old_patterntableposition=modplayer.patterntableposition;
1298         }
1299
1300         synthrender(samples, CHUNK_SIZE/2);
1301
1302         bytesdone += CHUNK_SIZE;
1303
1304         ci->pcmbuf_insert(samples, NULL, CHUNK_SIZE/2);
1305
1306     }
1307
1308     if (ci->request_next_track())
1309         goto next_track;
1310
1311     return CODEC_OK;
1312 }