Calculate abs(int) without branching

Wed, 13 Jan 2010 00:00:00 +0000

For this you need someone to teach it to you: if you made it yourself, then you are a very good Comp-Sci, and you should send your CV to Google ASAP. ;)

Without branching O_o?

Yes, without using any “if ( a < 0 )…”. To do that, you need to refresh how Two’s Complement works, then come back.

What we really need to focus on is that, given a signed int A, the negative of that number is: B = ~A + 1. BUT, we are trying to calculate the Absolute Value, not the negative. So, something like:

Twos-Complement on Zio Ivan

Calculate abs(int) without branching

Without branching O_o?