8bitworkshop/presets/vicdual/music.c

#include <string.h>

typedef unsigned char byte;
typedef unsigned short word;

// PLATFORM DEFINITION

__sfr __at (0x0) input0;
__sfr __at (0x1) input1;
__sfr __at (0x2) input2;
__sfr __at (0x3) input3;

__sfr __at (0x1) ay8910_reg;
__sfr __at (0x2) ay8910_data;
__sfr __at (0x40) palette;

byte __at (0xe000) cellram[28][32];
byte __at (0xe800) tileram[256][8];

#define LEFT1 !(input1 & 0x10)
#define RIGHT1 !(input1 & 0x20)
#define UP1 !(input1 & 0x40)
#define DOWN1 !(input1 & 0x80)
#define FIRE1 !(input2 & 0x20)
#define COIN1 (input3 & 0x8)
#define START1 !(input2 & 0x10)
#define START2 !(input3 & 0x20)
#define TIMER500HZ (input2 & 0x8)

// GAME CODE

void main();
void gsinit();

// start routine @ 0x0
void start() {
__asm
  	LD    SP,#0xE800 ; set up stack pointer
        DI		 ; disable interrupts
__endasm;
  	gsinit();
	main();
}

#define INIT_MAGIC 0xdeadbeef
static long is_initialized = INIT_MAGIC;

// set initialized portion of global memory
// by copying INITIALIZER area -> INITIALIZED area
void gsinit() {
  // already initialized? skip it
  if (is_initialized == INIT_MAGIC)
    return;
__asm
; copy initialized data to RAM
	LD    BC, #l__INITIALIZER
	LD    A, B
	LD    DE, #s__INITIALIZED
	LD    HL, #s__INITIALIZER
      	LDIR
__endasm;
}

// SOUND CODE

inline void set8910(byte reg, byte data) {
  ay8910_reg = reg;
  ay8910_data = data;
}

typedef enum {
  AY_PITCH_A_LO, AY_PITCH_A_HI,
  AY_PITCH_B_LO, AY_PITCH_B_HI,
  AY_PITCH_C_LO, AY_PITCH_C_HI,
  AY_NOISE_PERIOD,
  AY_ENABLE,
  AY_ENV_VOL_A,
  AY_ENV_VOL_B,
  AY_ENV_VOL_C,
  AY_ENV_PERI_LO, AY_ENV_PERI_HI,
  AY_ENV_SHAPE
} AY8910Register;

////////

// https://en.wikipedia.org/wiki/Linear-feedback_shift_register#Galois_LFSRs
static word lfsr = 1;
word rand() {
  unsigned lsb = lfsr & 1;   /* Get LSB (i.e., the output bit). */
  lfsr >>= 1;                /* Shift register */
  if (lsb) {                 /* If the output bit is 1, apply toggle mask. */
    lfsr ^= 0xB400u;
  }
  return lfsr;
}

void delay(byte msec) {
  while (msec--) {
    while (TIMER500HZ != 0) lfsr++;
    while (TIMER500HZ == 0) lfsr++;
  }
}

#define LOCHAR 0x0
#define HICHAR 0xff

#define CHAR(ch) (ch-LOCHAR)

void clrscr() {
  memset(cellram, CHAR(' '), sizeof(cellram));
}

byte getchar(byte x, byte y) {
  return cellram[x][y];
}

void putchar(byte x, byte y, byte attr) {
  cellram[x][y] = attr;
}

void putstring(byte x, byte y, const char* string) {
  while (*string) {
    putchar(x++, y, CHAR(*string++));
  }
}

// PC font (code page 437)
const byte font8x8[0x100][8] = {/*{w:8,h:8,bpp:1,count:256,xform:"scaleX(-1) rotate(90deg)"}*/
{ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }, { 0x7e,0x81,0x95,0xb1,0xb1,0x95,0x81,0x7e }, { 0x7e,0xff,0xeb,0xcf,0xcf,0xeb,0xff,0x7e }, { 0x0e,0x1f,0x3f,0x7e,0x3f,0x1f,0x0e,0x00 }, { 0x08,0x1c,0x3e,0x7f,0x3e,0x1c,0x08,0x00 }, { 0x38,0x3a,0x9f,0xff,0x9f,0x3a,0x38,0x00 }, { 0x10,0x38,0xbc,0xff,0xbc,0x38,0x10,0x00 }, { 0x00,0x00,0x18,0x3c,0x3c,0x18,0x00,0x00 }, { 0xff,0xff,0xe7,0xc3,0xc3,0xe7,0xff,0xff }, { 0x00,0x3c,0x66,0x42,0x42,0x66,0x3c,0x00 }, { 0xff,0xc3,0x99,0xbd,0xbd,0x99,0xc3,0xff }, { 0x70,0xf8,0x88,0x88,0xfd,0x7f,0x07,0x0f }, { 0x00,0x4e,0x5f,0xf1,0xf1,0x5f,0x4e,0x00 }, { 0xc0,0xe0,0xff,0x7f,0x05,0x05,0x07,0x07 }, { 0xc0,0xff,0x7f,0x05,0x05,0x65,0x7f,0x3f }, { 0x99,0x5a,0x3c,0xe7,0xe7,0x3c,0x5a,0x99 }, { 0x7f,0x3e,0x3e,0x1c,0x1c,0x08,0x08,0x00 }, { 0x08,0x08,0x1c,0x1c,0x3e,0x3e,0x7f,0x00 }, { 0x00,0x24,0x66,0xff,0xff,0x66,0x24,0x00 }, { 0x00,0x5f,0x5f,0x00,0x00,0x5f,0x5f,0x00 }, { 0x06,0x0f,0x09,0x7f,0x7f,0x01,0x7f,0x7f }, { 0xda,0xbf,0xa5,0xa5,0xfd,0x59,0x03,0x02 }, { 0x00,0x70,0x70,0x70,0x70,0x70,0x70,0x00 }, { 0x80,0x94,0xb6,0xff,0xff,0xb6,0x94,0x80 }, { 0x00,0x04,0x06,0x7f,0x7f,0x06,0x04,0x00 }, { 0x00,0x10,0x30,0x7f,0x7f,0x30,0x10,0x00 }, { 0x08,0x08,0x08,0x2a,0x3e,0x1c,0x08,0x00 }, { 0x08,0x1c,0x3e,0x2a,0x08,0x08,0x08,0x00 }, { 0x3c,0x3c,0x20,0x20,0x20,0x20,0x20,0x00 }, { 0x08,0x1c,0x3e,0x08,0x08,0x3e,0x1c,0x08 }, { 0x30,0x38,0x3c,0x3e,0x3e,0x3c,0x38,0x30 }, { 0x06,0x0e,0x1e,0x3e,0x3e,0x1e,0x0e,0x06 }, { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }, { 0x00,0x06,0x5f,0x5f,0x06,0x00,0x00,0x00 }, { 0x00,0x07,0x07,0x00,0x07,0x07,0x00,0x00 }, { 0x14,0x7f,0x7f,0x14,0x7f,0x7f,0x14,0x00 }, { 0x24,0x2e,0x6b,0x6b,0x3a,0x12,0x00,0x00 }, { 0x46,0x66,0x30,0x18,0x0c,0x66,0x62,0x00 }, { 0x30,0x7a,0x4f,0x5d,0x37,0x7a,0x48,0x00 }, { 0x04,0x07,0x03,0x00,0x00,0x00,0x00,0x00 }, { 0x00,0x1c,0x3e,0x63,0x41,0x00,0x00,0x00 }, { 0x00,0x41,0x63,0x3e,0x1c,0x00,0x00,0x00 }, { 0x08,0x2a,0x3e,0x1c,0x1c,0x3e,0x2a,0x08 }, { 0x08,0x08,0x3e,0x3e,0x08,0x08,0x00,0x00 }, { 0x00,0xa0,0xe0,0x60,0x00,0x00,0x00,0x00 }, { 0x08,0x08,0x08,0x08,0x08,0x08,0x00,0x00 }, { 0x00,0x00,0x60,0x60,0x00,0x00,0x00,0x00 }, { 0x60,0x30,0x18,0x0c,0x06,0x03,0x01,0x00 }, { 0x3e,0x7f,0x59,0x4d,0x7f,0x3e,0x00,0x00 }, { 0x42,0x42,0x7f,0x7f,0x40,0x40,0x00,0x00 }, { 0x62,0x73,0x59,0x49,0x6f,0x66,0x00,0x00 }, { 0x22,0x63,0x49,0x49,0x7f,0x36,0x00,0x00 }, { 0x18,0x1c,0x16,0x13,0x7f,0x7f,0x10,0x00 }, { 0x27,0x67,0x45,0x45,0x7d,0x39,0x00,0x00 }, { 0x3c,0x7e,0x4b,0x49,0x79,0x30,0x00,0x00 }, { 0x03,0x63,0x71,0x19,0x0f,0x07,0x00,0x00 }, { 0x36,0x7f,0x49,0x49,0x7f,0x36,0x00,0x00 }, { 0x06,0x4f,0x49,0x69,0x3f,0x1e,0x00,0x00 }, { 0x00,0x00,0x6c,0x6c,0x00,0x00,0x00,0x00 }, { 0x00,0xa0,0xec,0x6c,0x00,0x00,0x00,0x00 }, { 0x08,0x1c,0x36,0x63,0x41,0x00,0x00,0x00 }, { 0x14,0x14,0x14,0x14,0x14,0x14,0x00,0x00 }, { 0x00,0x41,0x63,0x36,0x1c,0x08,0x00,0x00 }, { 0x02,0x03,0x51,0x59,0x0f,0x06,0x00,0x00 }, { 0x3e,0x7f,0x41,0x5d,0x5d,0x1f,0x1e,0x00 }, { 0x7c,0x7e,0x13,0x13,0x7e,0x7c,0x00,0x00 }, { 0x41,0x7f,0x7f,0x49,0x49,0x7f,0x36,0x00 }, { 0x1c,0x3e,0x63,0x41,0x41,0x63,0x22,0x00 }, { 0x41,0x7f,0x7f,0x41,0x63,0x7f,0x1c,0x00 }, { 0x41,0x7f,0x7f,0x49,0x5d,0x41,0x63,0x00 }, { 0x41,0x7f,0x7f,0x49,0x1d,0x01,0x03,0x00 }, { 0x1c,0x3e,0x63,0x41,0x51,0x73,0x72,0x00 }, { 0x7f,0x7f,0x08,0x08,0x7f,0x7f,0x00,0x00 }, { 0x00,0x41,0x7f,0x7f,0x41,0x00,0x00,0x00 }, { 0x30,0x70,0x40,0x41,0x7f,0x3f,0x01,0x00 }, { 0x41,0x7f,0x7f,0x08,0x1c,0x77,0x63,0x00 }, { 0x41,0x7f,0x7f,0x41,0x40,0x60,0x70,0x00 }, { 0x7f,0x7f,0x06,0x0c,0x06,0x7f,0x7f,0x00 }, { 0x7f,0x7f,0x06,0x0c,0x18,0x7f,0x7f,0x00 }, { 0x1c,0x3e,0x63,0x41,0x63,0x3e,0x1c,0x00 }, { 0x41,0x7f,0x7f,0x49,0x09,0x0f,0x06,0x00 }, { 0x1e,0x3f,0x21,0x71,0x7f,0x5e,0x00,0x00 }, { 0x41,0x7f,0x7f,0x19,0x39,0x6f,0x46,0x00 }, { 0x26,0x67,0x4d,0x59,0x7b,0x32,0x00,0x00 }, { 0x03,0x41,0x7f,0x7f,0x41,0x03,0x00,0x00 }, { 0x7f,0x7f,0x40,0x40,0x7f,0x7f,0x00,0x00 }, { 0x1f,0x3f,0x60,0x60,0x3f,0x1f,0x00,0x00 }, { 0x7f,0x7f,0x30,0x18,0x30,0x7f,0x7f,0x00 }, { 0x63,0x77,0x1c,0x08,0x1c,0x77,0x63,0x00 }, { 0x07,0x4f,0x78,0x78,0x4f,0x07,0x00,0x00 }, { 0x67,0x73,0x59,0x4d,0x47,0x63,0x71,0x00 }, 
};

const char BOX_CHARS[8] = { 218, 191, 192, 217, 196, 196, 179, 179 };

void draw_box(byte x, byte y, byte x2, byte y2, const char* chars) {
  byte x1 = x;
  putchar(x, y, chars[2]);
  putchar(x2, y, chars[3]);
  putchar(x, y2, chars[0]);
  putchar(x2, y2, chars[1]);
  while (++x < x2) {
    putchar(x, y, chars[5]);
    putchar(x, y2, chars[4]);
  }
  while (++y < y2) {
    putchar(x1, y, chars[6]);
    putchar(x2, y, chars[7]);
  }
}

//
// MUSIC ROUTINES
//

// 440.5 1.79270256703 49
const int note_table[64] = {
4305, 4063, 3835, 3620, 3417, 3225, 3044, 2873, 2712, 2560, 2416, 2280, 2152, 2032, 1918, 1810, 1708, 1612, 1522, 1437, 1356, 1280, 1208, 1140, 1076, 1016, 959, 905, 854, 806, 761, 718, 678, 640, 604, 570, 538, 508, 479, 452, 427, 403, 380, 359, 339, 320, 302, 285, 269, 254, 240, 226, 214, 202, 190, 180, 169, 160, 151, 143, 135, 127, 120, 113, };

struct {
  byte volume;
} voice[3];

byte music_index = 0;
byte cur_duration = 0;

const byte music1[] = {
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};

static const byte* music_ptr = music1;

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

void play_music() {
  byte ch;
  byte enable = 0;
  byte freech = 0;
  byte chmask = 1;
  for (ch=0; ch<3; ch++) {
    if (voice[ch].volume) {
      set8910(AY_ENV_VOL_A+ch, voice[ch].volume--);
      enable |= chmask;
    } else {
      freech = ch;
    }
    chmask <<= 1;
  }
  set8910(AY_ENABLE, ~enable);
  if (music_ptr) {
    ch = freech;
    while (cur_duration == 0) {
      byte note = next_music_byte();
      if ((note & 0x80) == 0) {
        int period = note_table[note & 63];
        set8910(AY_PITCH_A_LO+ch*2, period & 0xff);
        set8910(AY_PITCH_A_HI+ch*2, period >> 8);
        voice[ch].volume = 15;
        ch = ch ? ch-1 : 2;
      } else {
        if (note == 0xff)
          music_ptr = NULL;
        cur_duration = note & 63;
      }
    }
    cur_duration--;
  }
}

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

void main() {
  palette = 0;
  memset(cellram, 0, sizeof(cellram));
  memcpy(tileram, font8x8, sizeof(font8x8));
  draw_box(0, 0, 27, 31, BOX_CHARS);
  music_ptr = 0;
  while (1) {
    if (!music_ptr) start_music(music1);
    play_music();
    delay(8);
  }
}