private void volume_slide() {
		int up, down;
		up = ( volume_slide_param & 0xF0 ) >> 4;
		down = volume_slide_param & 0x0F;
		if( down == 0x0F && up > 0 ) {
			/* Fine slide up.*/
			if( effect_tick == 0 ) {
				set_volume( volume + up );
			}
		} else if( up == 0x0F && down > 0 ) {
			/* Fine slide down.*/
			if( effect_tick == 0 ) {
				set_volume( volume - down );
			}
		} else {
			/* Normal slide.*/
			if( effect_tick > 0 || fast_volume_slides ) {
				set_volume( volume + up - down );
			}
		}
	}