8bitworkshop/presets/c64/musicplayer.c

/*
A simple music player.
*/

#include "common.h"
//#link "common.c"

// SID frequency table (PAL version)
const int note_table_pal[96] = {
278,295,313,331,351,372,394,417,442,468,496,526,557,590,625,662,702,743,788,834,884,937,992,1051,1114,1180,1250,1325,1403,1487,1575,1669,1768,1873,1985,2103,2228,2360,2500,2649,2807,2973,3150,3338,3536,3746,3969,4205,4455,4720,5001,5298,5613,5947,6300,6675,7072,7493,7938,8410,8910,9440,10001,10596,11226,11894,12601,13350,14144,14985,15876,16820,17820,18880,20003,21192,22452,23787,25202,26700,28288,29970,31752,33640L,35641L,37760L,40005L,42384L,44904L,47574L,50403L,53401L,56576L,59940L,63504L,67280L
};

#define NOTE_TABLE note_table_pal

// SID utility routines

void sid_init() {
  SID.amp = 0x0f; // volume 15, no filters
}

#define SID_PULSE_DECAY(voice, period) \
  SID.voice.ctrl = 0x00; \
  SID.voice.freq = period; \
  SID.voice.pw = 0x7f; \
  SID.voice.ad = 0x88; \
  SID.voice.sr = 0x48; \
  SID.voice.ctrl = 0x31; \

// music player logic

byte music_index = 0;
byte cur_duration = 0;

const byte music1[]; // music data -- see end of file
const byte* music_ptr = music1;

byte next_music_byte() {
  return *music_ptr++;
}

void play_music() {
  static byte chs = 0;
  if (music_ptr) {
    // run out duration timer yet?
    while (cur_duration == 0) {
      // fetch next byte in score
      byte note = next_music_byte();
      // is this a note?
      if ((note & 0x80) == 0) {
        int period = NOTE_TABLE[note & 63];
        // see which pulse generator is free
        if (!(chs & 1)) {
          SID_PULSE_DECAY(v1, period);
          chs |= 1;
        } else if (!(chs & 2)) {
          SID_PULSE_DECAY(v2, period);
          chs |= 2;
        } else if (!(chs & 4)) {
          SID_PULSE_DECAY(v3, period);
          chs |= 4;
        }
      } else {
        // end of score marker
        if (note == 0xff)
          music_ptr = NULL;
        // set duration until next note
        cur_duration = note & 63;
        // reset channel used mask
        chs = 0;
      }
    }
    cur_duration--;
  }
}

void start_music(const byte* music) {
  music_ptr = music;
  cur_duration = 0;
}

void main(void)
{
  sid_init();
  music_ptr = 0;
  while (1) {
    if (!music_ptr) start_music(music1);
    wait_vblank();
    play_music();
  }
}

//
// MUSIC DATA -- "The Easy Winners" by Scott Joplin
//
const byte music1[] = {
0x2a,0x1e,0x95,0x33,0x27,0x9f,0x31,0x25,0x8a,0x2f,0x23,0x8b,0x2e,0x22,0x89,0x2c,0x20,0x8b,0x2a,0x1e,0x95,0x28,0x1c,0x8a,0x27,0x1b,0x95,0x25,0x19,0x8b,0x23,0x17,0x89,0x22,0x12,0x8b,0x23,0x8a,0x25,0x8b,0x27,0x89,0x28,0x1e,0x8c,0x2a,0x1c,0x89,0x2c,0x1b,0x8c,0x2e,0x19,0x89,0x2f,0x17,0x95,0x27,0x23,0x1e,0x95,0x12,0x95,0x23,0x1e,0x27,0x95,0x2f,0x33,0x17,0x95,0x2f,0x33,0x27,0x94,0x12,0x95,0x33,0x36,0x23,0x95,0x38,0x32,0x17,0x8b,0x33,0x36,0x89,0x1e,0x27,0x23,0x8b,0x38,0x32,0x8a,0x33,0x36,0x12,0x8b,0x32,0x38,0x89,0x36,0x33,0x27,0x95,0x3d,0x37,0x10,0x8b,0x3b,0x38,0x8a,0x20,0x23,0x28,0x8b,0x37,0x3d,0x89,0x38,0x3b,0x10,0x8b,0x37,0x3d,0x8a,0x3b,0x38,0x28,0x8b,0x36,0x33,0x8a,0x17,0x95,0x2a,0x1e,0x23,0x8b,0x2c,0x89,0x2e,0x12,0x8b,0x2f,0x8a,0x31,0x27,0x23,0x8b,0x32,0x89,0x2f,0x33,0x17,0x95,0x33,0x2f,0x1e,0x95,0x12,0x94,0x36,0x33,0x1e,0x95,0x32,0x38,0x17,0x8b,0x36,0x33,0x89,0x23,0x1e,0x27,0x8b,0x38,0x32,0x8a,0x33,0x36,0x18,0x8b,0x33,0x36,0x8a,0x33,0x36,0x2a,0x95,0x36,0x19,0x8b,0x31,0x2e,0x89,0x25,0x22,0x2a,0x8b,0x36,0x8a,0x2f,0x35,0x19,0x8b,0x36,0x89,0x38,0x2f,0x29,0x95,0x2e,0x36,0x1e,0x95,0x1c,0x28,0x95,0x27,0x1b,0x8b,0x2a,0x8a,0x2e,0x25,0x19,0x8b,0x34,0x89,0x33,0x2f,0x23,0x95,0x33,0x2f,0x1e,0x95,0x12,0x94,0x33,0x36,0x23,0x95,0x32,0x38,0x17,0x8b,0x33,0x36,0x8a,0x23,0x27,0x1e,0x8b,0x38,0x32,0x89,0x36,0x33,0x12,0x8b,0x32,0x38,0x8a,0x33,0x36,0x1e,0x94,0x37,0x3d,0x10,0x8b,0x3b,0x38,0x8a,0x23,0x28,0x20,0x8b,0x3d,0x37,0x89,0x3b,0x38,0x1c,0x8b,0x38,0x3b,0x8a,0x3a,0x3d,0x38,0x8b,0x3f,0x37,0x3a,0x89,0x27,0x1b,0x8b,0x33,0x8a,0x37,0x22,0x16,0x8b,0x3a,0x8a,0x3f,0x0f,0x1b,0x95,0x3a,0x8b,0x3b,0x8a,0x3d,0x37,0x1c,0x8b,0x3b,0x38,0x89,0x23,0x28,0x20,0x8b,0x3d,0x37,0x8a,0x38,0x3b,0x10,0x8b,0x3d,0x37,0x89,0x38,0x3b,0x20,0x8b,0x36,0x33,0x8a,0x17,0x23,0x8b,0x38,0x34,0x8a,0x33,0x36,0x1e,0x8b,0x31,0x34,0x8a,0x2f,0x33,0x17,0x8b,0x36,0x33,0x8a,0x23,0x27,0x1e,0x8b,0x33,0x36,0x8a,0x36,0x30,0x12,0x8a,0x34,0x31,0x8a,0x1e,0x28,0x22,0x8b,0x30,0x36,0x89,0x34,0x31,0x12,0x8b,0x2e,0x28,0x33,0x8a,0x31,0x28,0x2e,0x95,0x27,0x2f,0x1e,0x95,0x12,0x95,0x14,0x94,0x16,0x95,0x2f,0x33,0x17,0x95,0x2f,0x33,0x27,0x94,0x12,0x95,0x36,0x33,0x23,0x95,0x32,0x38,0x17,0x8a,0x33,0x36,0x8a,0x23,0x27,0x1e,0x8b,0x32,0x38,0x8a,0x33,0x36,0x12,0x8b,0x38,0x32,0x8a,0x36,0x33,0x27,0x95,0x3d,0x37,0x10,0x8a,0x3b,0x38,0x8a,0x23,0x28,0x20,0x8b,0x37,0x3d,0x89,0x3b,0x38,0x10,0x8b,0x37,0x3d,0x8a,0x38,0x3b,0x23,0x8b,0x36,0x33,0x8a,0x17,0x95,0x2a,0x1e,0x23,0x8b,0x2c,0x8a,0x2e,0x12,0x8b,0x2f,0x89,0x31,0x23,0x1e,0x8b,0x32,0x8a,0x33,0x2f,0x17,0x95,0x2f,0x33,0x1e,0x94,0x12,0x95,0x36,0x33,0x27,0x95,0x38,0x32,0x17,0x8a,0x36,0x33,0x8a,0x23,0x1e,0x27,0x8b,0x38,0x32,0x89,0x33,0x36,0x18,0x8c,0x36,0x33,0x89,0x33,0x36,0x21,0x95,0x36,0x19,0x8b,0x2e,0x31,0x8a,0x25,0x2a,0x22,0x8b,0x36,0x89,0x35,0x2f,0x19,0x8b,0x36,0x8a,0x2f,0x38,0x25,0x94,0x36,0x2e,0x2a,0x95,0x1c,0x28,0x95,0x27,0x1b,0x8c,0x2a,0x89,0x2e,0x25,0x19,0x8b,0x34,0x8a,0x33,0x2f,0x23,0x95,0x2f,0x33,0x1e,0x94,0x12,0x95,0x33,0x36,0x23,0x95,0x32,0x38,0x17,0x8a,0x33,0x36,0x8a,0x23,0x1e,0x27,0x8b,0x32,0x38,0x89,0x36,0x33,0x12,0x8c,0x32,0x38,0x89,0x33,0x36,0x1e,0x95,0x37,0x3d,0x10,0x8b,0x3b,0x38,0x8a,0x23,0x20,0x28,0x8a,0x3d,0x37,0x8a,0x38,0x3b,0x1c,0x8b,0x3b,0x38,0x8a,0x3d,0x38,0x3a,0x8b,0x3a,0x3f,0x37,0x89,0x27,0x1b,0x8b,0x33,0x8a,0x37,0x22,0x16,0x8b,0x3a,0x8a,0x3f,0x0f,0x1b,0x95,0x3a,0x8b,0x3b,0x8a,0x3d,0x37,0x1c,0x8b,0x3b,0x38,0x8a,0x20,0x28,0x23,0x8b,0x3d,0x37,0x89,0x38,0x3b,0x10,0x8b,0x3d,0x37,0x8a,0x38,0x3b,0x20,0x8b,0x33,0x36,0x89,0x17,0x23,0x8b,0x38,0x34,0x8a,0x36,0x33,0x23,0x8b,0x34,0x31,0x89,0x2f,0x33,0x17,0x8c,0x36,0x33,0x89,0x1e,0x27,0x23,0x8c,0x33,0x36,0x89,0x36,0x30,0x12,0x8b,0x34,0x31,0x8a,0x1e,0x28,0x22,0x8a,0x30,0x36,0x8a,0x34,0x31,0x1e,0x8b,0x28,0x2e,0x33,0x89,0x28,0x31,0x2e,0x95,0x27,0x2f,0x17,0x95,0x12,0x1e,0x95,0x3b,0x36,0x33,0x96,0x2a,0x8b,0x2b,0x8a,0x2c,0x1e,0x12,0x8b,0x2d,0x89,0x2e,0x28,0x1e,0x8b,0x2e,0x31,0x8a,0x16,0x22,0x8b,0x36,0x89,0x34,0x1e,0x22,0x8b,0x31,0x8a,0x2c,0x25,0x19,0x8b,0x2d,0x89,0x2e,0x28,0x25,0x8b,0x33,0x2e,0x8a,0x25,0x19,0x8c,0x31,0x89,0x2c,0x1a,0x26,0x8b,0x2e,0x8a,0x2f,0x1b,0x27,0x8b,0x2a,0x89,0x2c,0x23,0x1e,0x8b,0x2e,0x8a,0x2f,
};