Not a review - I would like to offer my fixed_pt code as an example, and placed it here: http://www.bitbucket.org/nbecker/fixed_pt/src/ Notes: 1) This is a fixed_pt class for run-time parameterization of bit widths. I'm using it to interface with python (so a compile-time parameterization would not be useful) 2) Some others have suggested different semantics for fixed_pt numbers. In particular, there is question about whether arithmetic operations on numbers of some bit-widths should give results of different bit-widths. I've elected to have operands and results have the same widths.