void YM2612_write(const u16 port, const u8 data)
{
    vs8 *pb;

    pb = (u8*)  0xA04000;

    // wait while YM2612 busy
    while (*pb < 0);
    // write data
    pb[port & 3] = data;
}

void YM2612_reset()
{

// code removed for brevity //

// enable left and right output for all channel
    for(i = 0; i < 3; i++)
    {
        YM2612_write(0, 0xB4 | i);
        YM2612_write(1, 0xC0);
        YM2612_write(2, 0xB4 | i);
        YM2612_write(3, 0xC0);
    }

// code removed for brevity //

}