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[emacs.git] / lisp / float-sup.el
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1 ;;; float-sup.el --- detect absence of floating-point support in Emacs runtime
3 ;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc.
5 ;; Maintainer: FSF
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 2, or (at your option)
12 ;; any later version.
14 ;; GNU Emacs is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to the
21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 ;; Boston, MA 02111-1307, USA.
24 ;;; Code:
26 ;; Provide a meaningful error message if we are running on
27 ;; bare (non-float) emacs.
28 ;; Can't test for 'floatp since that may be defined by float-imitation
29 ;; packages like float.el in this very directory.
31 (if (fboundp 'atan)
32 nil
33 (error "Floating point was disabled at compile time"))
35 ;; provide an easy hook to tell if we are running with floats or not.
36 ;; define pi and e via math-lib calls. (much less prone to killer typos.)
37 (defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...)")
38 (defconst e (exp 1) "The value of e (2.7182818...)")
40 ;; Careful when editing this file ... typos here will be hard to spot.
41 ;; (defconst pi 3.14159265358979323846264338327
42 ;; "The value of Pi (3.14159265358979323846264338327...)")
44 (defconst degrees-to-radians (/ pi 180.0)
45 "Degrees to radian conversion constant")
46 (defconst radians-to-degrees (/ 180.0 pi)
47 "Radian to degree conversion constant")
49 ;; these expand to a single multiply by a float when byte compiled
51 (defmacro degrees-to-radians (x)
52 "Convert ARG from degrees to radians."
53 (list '* (/ pi 180.0) x))
54 (defmacro radians-to-degrees (x)
55 "Convert ARG from radians to degrees."
56 (list '* (/ 180.0 pi) x))
58 (provide 'lisp-float-type)
60 ;;; float-sup.el ends here