[HECnet] Re: quick help on RSX FORTRAN problem?

   Since Fortran 77 is not much fun without floating point, you may want to try the RSX Floating Point Emulator.    Glenn Everhart released this floating point emulator on the Fall 82 RSX SIG tape in [312,315].  In 1984, my lab acquired a PDP-11/44 but it did not have a FPP. We used this FPEM software to be able to use Fortran 77 floating point operations. At that time we were running RSX11M+ V2.1 or maybe V3.0 It continued to be used until at least 1993 or so.    It works by putting a vector to its code which it partially locates in pool to trap illegal instructions. If the instruction was a FP instruction then it does the work in software and returns to the user code. It should be FIXed in memory, if it is checkpoint or moved by a shuffle to a different location after it runs, it will crash RSX. I’d fix it in memory early in STARTUP.CMD.    I did verify that the FPEM.MAC compiles & links clean on RSX11M+ V4.6, but I didn’t have an easy way to test it. Below is a bit more info on it that is also in FPEM.DOC