On 08/10/2012 03:58 PM, hvlems at zonnet.nl wrote: Is gcc the only option you've got Paul? Gcc must satisfy a lot of terget platforms, may be optimal gets defined differently? Pardon me for jumping in here, but I know something about this part. GCC's code generation back-end is very tightly tuned for the target processor. C code (or C++, or FORTRAN, ADA, Pascal, or any other language GCC supports) is compiled to an intermediate RTL (register transfer language) and then passed to the code generation back-end. Various types of optimization, some language-specific and some not, some target-specific and some not, are applied at various stages. The end result is a situation in which the quality of the emitted executable code for one architecture typically does not suffer when another has had improvements made to it. -Dave -- Dave McGuire, AK4HZ New Kensington, PA