title: What exactly means U0.8, U4.8, U12.8, S0.4, S4.4, S12.4, U8.8 etc. fixed-point representation?
body: <p>I'm finding it hard to understand fixed-point representations. When I have unsigned type of data (C++) and I want to work with that number as if it is fixed-point, I need do do certain amount of bit manipulation which aren't clear to me.</p>
  
  <p>So let's say I want that my number which is unsigned and can be max 255 (8 bit number) be represented in U4.4 or U12.8 or S13.8 or whichever notation (U - unsigned, S - signed, and it comes in question when my number is int). Basically I'm expanding (or I hope that I'm) the number, working on it, and then returning it to the previous state.</p>
  
  <p>How do I do that? </p>
  
  <p>Can someone share link where I can find something closely related to this subject. I was looking for three hours and all I have found are general explanations on fixed-point arithmetics, nothing very practical.</p>
  
  <p>Thanks</p>