| 1 | ;;; float-sup.el --- detect absence of floating-point support in Emacs runtime |
| 2 | |
| 3 | ;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Maintainer: FSF |
| 6 | |
| 7 | ;; This file is part of GNU Emacs. |
| 8 | |
| 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. |
| 13 | |
| 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. |
| 18 | |
| 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 |
| 21 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 22 | |
| 23 | ;;; Code: |
| 24 | |
| 25 | ;; Provide a meaningful error message if we are running on |
| 26 | ;; bare (non-float) emacs. |
| 27 | ;; Can't test for 'floatp since that may be defined by float-imitation |
| 28 | ;; packages like float.el in this very directory. |
| 29 | |
| 30 | (if (fboundp 'atan) |
| 31 | nil |
| 32 | (error "Floating point was disabled at compile time")) |
| 33 | |
| 34 | ;; provide an easy hook to tell if we are running with floats or not. |
| 35 | ;; define pi and e via math-lib calls. (much less prone to killer typos.) |
| 36 | (defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...)") |
| 37 | (defconst e (exp 1) "The value of e (2.7182818...)") |
| 38 | |
| 39 | ;; Careful when editing this file ... typos here will be hard to spot. |
| 40 | ;; (defconst pi 3.14159265358979323846264338327 |
| 41 | ;; "The value of Pi (3.14159265358979323846264338327...)") |
| 42 | |
| 43 | (defconst degrees-to-radians (/ pi 180.0) |
| 44 | "Degrees to radian conversion constant") |
| 45 | (defconst radians-to-degrees (/ 180.0 pi) |
| 46 | "Radian to degree conversion constant") |
| 47 | |
| 48 | ;; these expand to a single multiply by a float when byte compiled |
| 49 | |
| 50 | (defmacro degrees-to-radians (x) |
| 51 | "Convert ARG from degrees to radians." |
| 52 | (list '* (/ pi 180.0) x)) |
| 53 | (defmacro radians-to-degrees (x) |
| 54 | "Convert ARG from radians to degrees." |
| 55 | (list '* (/ 180.0 pi) x)) |
| 56 | |
| 57 | (provide 'lisp-float-type) |
| 58 | |
| 59 | ;;; float-sup.el ends here |