title: How can hex addition in BC be made to overflow at the 8 byte limit (uint64)?
body: <p>I am adding a series of 8196 64-bit unsigned integers, and I need the running-total to "roll-over" back to zero and continue counting from there... just as a "normal" programing language would do at the relevent INT_MAX ceiling.    </p>
  
  <p>As the test script shows, adding 1 to an boundary value (FF, FFFF, etc) just keeps on increasing the total. A feature, no doubt, but I'd like to limit it to 64-bits for this particular instance..   </p>
  
  <p>Is there some way to limit <code>bc</code> in this?</p>
  
  <pre><code>unset f 
  for ((i=0; i&lt;8; i++)); do 
    f=${f}FF; echo -ne "$((${#f}/2)) bytes + 1      " 
    echo 'ibase=16; obase=10; ('$f'+1)' |bc 
  done
  echo "I want 8th+1 to = 0000000000000000"
  
  # output
  #
  # 1 bytes + 1      100
  # 2 bytes + 1      10000
  # 3 bytes + 1      1000000
  # 4 bytes + 1      100000000
  # 5 bytes + 1      10000000000
  # 6 bytes + 1      1000000000000
  # 7 bytes + 1      100000000000000
  # 8 bytes + 1      10000000000000000
  # I want 8th+1 to = 0000000000000000
  </code></pre>