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1.1 ! root 1: Notes on xcalc: ! 2: ! 3: I've gotten the sucker to run on an IBM RT, under BSD 4.2, and on a MicroVAX ! 4: GPX, under Ultrix 1.2. The RT is lucky enough to have the IEEE math routines. ! 5: Under these routines, if you say "x = 1.0 / 0.0", it doesn't blow up. ! 6: Instead, when you decide to printf() x, it shows up as "INF". The routines ! 7: also have the nice feature of being terribly accurate. Needless to say, this ! 8: all makes writing a calculator fun/E-Z. ! 9: ! 10: On the MicroVAX, however, I had to use a wretched math package, one that only ! 11: goes between 1E-38 and 1E+38, one that isn't very accurate, and one that will ! 12: cause an FP Exception at the slightest prompting. As a result, I had to put ! 13: in all sorts of evil nasty 'sigvec's and 'setjmp's and things. I think it ! 14: takes away from the intrinsic beauty (hah!) of the code, but at least it ! 15: doesn't say "floating exception: core dumped" anymore, so it's a step in ! 16: the right direction. ! 17: ! 18: The point is: If you're lucky enough to have the IEEE routines, by all means ! 19: add a -DIEEE to the CFLAGS line in the Makefile. ! 20: ! 21: -jhb, 3/16/86
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