int x, y, address;
byte data, checksum, upper, lower;

address = 0;
for (y=0 to 255) {
      checksum = 0;
      for (x = 0 to 255) {
            data = memory[address++];
            checksum += data;
            data += (data >= 10) ? (-10 + "a") : "0";
            uart.load(data);
      }
      upper = (checksum >> 4) &  8'h0f;
      upper += (upper >= 10) ? (-10 + "a") : "0";
      uart.load(upper);
      lower = checksum &  8'h0f;
      lower += (lower >= 10) ? (-10 + "a") : "0";
      uart.load(lower);
      uart.load(LF);
}