Message #226805

[ZippyDee]

Er...no, you should be starting on the right still...

I believe jacobly's post should have said:

         11001100 = a
       × 10010110 = b
       ----------
         00000000
        11001100
       11001100
      00000000
     11001100
    00000000
   00000000
+ 11001100
-----------------
  111011110001000

So as you can see, in binary, for each bit you add either 0 or a (shifted by some amount), depending on the corresponding bit in b.
The way this is usually done is:
    1. shift the running total left one bit
    2. check the lsb of b
    3. if set, add a to the running total
    4. shift b right one bit
    5. repeat steps 1-4 for each bit in b
    6. the answer is the current running total