I'm having trouble with a fairly simply concept, signed binary arithmetic. I know how to do 1's and 2's complement, convert from binary, decimal, octal, and hex, multiply and add bytes and bits, but for some reason this is stumping me:
77 - 99 + 44 for example.
77 > 01001101 -(99) > 01100011 10011100 + 1 2's complement 10011101 44 > 00101100
At this point, I thought I could just take the sum of 77 and the 2's complement of 99, but I feel like I'm going in the wrong direction after completing that step and then adding 44, like below:
77 > 01001101 -(99) > + 10011101 = 00000010 44 > + 00101100 (cut off ending 1, past 8) = 00101111
What am I missing? Thanks
Update: I've followed this example, and it shows that when dealing with a 1 (negative) sign bit in a given result, to do another 2's complement with the result, but I am not getting that result.