Anonymous, alluding to Bill Thacker. The advantages of portable code are well known. This section gives some guidelines for writing portable code.
Optimized code is often obscure.
Optimizations for one machine may produce worse code on another. Document performance hacks and localize them as much as possible. Recognize that some things are inherently non-portable. Even in these cases there are many routines and data organizations that can be made machine independent. Then if the program is to be moved to a new machine, it is a much easier task to determine what needs to be changed.