Bit Manipulation

This post is about Bit Manipulation. I will add more content later.

I tend to forget how negative integers are represented in binary a lot. So here is how:

base 10     base2(using two's complement)
 18             00010010
-18             11101110


  0010010
+1101101 +1
------------------
 01111111 +1

Step1: We first flip the digit of positive 18  = 1101101

  0010010
+1101110
------------------
10000000

Step2: and then add 1 to it. 1101101 + 1  = 1101110


1 1101110 is negative 18, the first 1 is the sign.

Masks

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