bit twiddling n. [very common] 1. (pejorative) An exercise in tuning (see tune ) in which incredible amounts of time and effort go to produce little noticeable improvement, often with the result that the code becomes incomprehensible. 2. Aimless small modification to a program, esp. for some pointless goal. 3. Approx. syn. for bit bashing ; esp. used for the act of frobbing the device control register of a peripheral in an attempt to get it back to a known state.