sound.c

开放源码的编译器open watcom 1.6.0版的源代码

#include <i86.h>

/*
    The numbers in this table are the timer divisors
    necessary to produce the pitch indicated in the
    lowest octave that is supported by the "sound"
    function.

    To raise the pitch by N octaves, simply divide the
    number in the table by 2**N since a pitch which is
    an octave above another has double the frequency of
    the original pitch.

    The frequency obtained by these numbers is given by
    1193180 / X where X is the number obtained in the
    table.
*/

unsigned short Notes[] = {
        19327 ,        /* C b            */
        18242 ,        /* C              */
        17218 ,        /* C #   ( D b )  */
        16252 ,        /* D              */
        15340 ,        /* D #   ( E b )  */
        14479 ,        /* E     ( F b )  */
        13666 ,        /* F     ( E # )  */
        12899 ,        /* F #   ( G b )  */
        12175 ,        /* G              */
        11492 ,        /* G #   ( A b )  */
        10847 ,        /* A              */
        10238 ,        /* A #   ( B b )  */
        9664 ,         /* B     ( C b )  */
        9121 ,         /* B #            */
        0
};

#define FACTOR  1193180
#define OCTAVE  4

void main()             /* play the scale */
  {
    int i;
    for( i = 0; Notes[i]; ++i ) {
      sound( FACTOR / (Notes[i] / (1 << OCTAVE)) );
      delay( 200 );
      nosound();
    }
  }