public void calculateChecksum(IPatch ip, int start, int end, int ofs) {
public void calculateChecksum(Patch ip, int start, int end, int ofs) {
  public void calculateChecksum(IPatch ip, int start, int end, int ofs) {  	Patch p = (Patch)ip;  	int sum = 0;    for (int i = start; i <= end; i++) {      sum += p.sysex[i];    }    p.sysex[ofs] = (byte)(sum & 0x7F);  }