Hi,
what you wrote in your message '[Maxima] replacing basic Fortran
functions' is a very sensible thing ti do - to replace the very
unidiomatic code translated from Fortran with better lisp code. It might
be slower than the original Fortran, but then it would at least be more
readable. Using higher level lisp tools, it could even be faster some
time!
Given enough time I could even be persuaded to help you in the process
:-)
Andreas Eder