void hvl_GenWhiteNoise( int8 *buf, uint32 len )
{
  uint32 ays;

  ays = 0x41595321;

  do {
    uint16 ax, bx;
    int8 s;

    s = ays;

    if( ays & 0x100 )
    {
      s = 0x7f;

      if( ays & 0x8000 )
        s = 0x80;
    }

    *buf++ = s;
    len--;

    ays = (ays >> 5) | (ays << 27);
    ays = (ays & 0xffffff00) | ((ays & 0xff) ^ 0x9a);
    bx  = ays;
    ays = (ays << 2) | (ays >> 30);
    ax  = ays;
    bx  += ax;
    ax  ^= bx;
    ays  = (ays & 0xffff0000) | ax;
    ays  = (ays >> 3) | (ays << 29);
  } while( len );
}