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49e4877c | 1 | # fpieee.m4 serial 2 -*- coding: utf-8 -*- |
7a6dbc2f | 2 | dnl Copyright (C) 2007, 2009-2018 Free Software Foundation, Inc. |
88b48903 WN |
3 | dnl This file is free software; the Free Software Foundation |
4 | dnl gives unlimited permission to copy and/or distribute it, | |
5 | dnl with or without modifications, as long as this notice is preserved. | |
6 | ||
7 | dnl IEEE 754 standardized three items: | |
8 | dnl - The formats of single-float and double-float - nowadays commonly | |
9 | dnl available as 'float' and 'double' in C and C++. | |
10 | dnl No autoconf test needed. | |
11 | dnl - The overflow and division by zero behaviour: The result are values | |
12 | dnl '±Inf' and 'NaN', rather than exceptions as it was before. | |
13 | dnl This file provides an autoconf macro for ensuring this behaviour of | |
14 | dnl floating-point operations. | |
15 | dnl - A set of conditions (overflow, underflow, inexact, etc.) which can | |
16 | dnl be configured to trigger an exception. | |
17 | dnl This cannot be done in a portable way: it depends on the compiler, | |
18 | dnl libc, kernel, and CPU. No autoconf macro is provided for this. | |
19 | ||
20 | dnl Ensure non-trapping behaviour of floating-point overflow and | |
21 | dnl floating-point division by zero. | |
22 | dnl (For integer overflow, see gcc's -ftrapv option; for integer division by | |
23 | dnl zero, see the autoconf macro in intdiv0.m4.) | |
24 | ||
25 | AC_DEFUN([gl_FP_IEEE], | |
26 | [ | |
27 | AC_REQUIRE([AC_PROG_CC]) | |
28 | AC_REQUIRE([AC_CANONICAL_HOST]) | |
29 | # IEEE behaviour is the default on all CPUs except Alpha and SH | |
30 | # (according to the test results of Bruno Haible's ieeefp/fenv_default.m4 | |
31 | # and the GCC 4.1.2 manual). | |
32 | case "$host_cpu" in | |
33 | alpha*) | |
34 | # On Alpha systems, a compiler option provides the behaviour. | |
35 | # See the ieee(3) manual page, also available at | |
7a6dbc2f | 36 | # <https://backdrift.org/man/tru64/man3/ieee.3.html> |
88b48903 WN |
37 | if test -n "$GCC"; then |
38 | # GCC has the option -mieee. | |
39 | # For full IEEE compliance (rarely needed), use option -mieee-with-inexact. | |
40 | CPPFLAGS="$CPPFLAGS -mieee" | |
41 | else | |
42 | # Compaq (ex-DEC) C has the option -ieee, equivalent to -ieee_with_no_inexact. | |
43 | # For full IEEE compliance (rarely needed), use option -ieee_with_inexact. | |
44 | CPPFLAGS="$CPPFLAGS -ieee" | |
45 | fi | |
46 | ;; | |
47 | sh*) | |
48 | if test -n "$GCC"; then | |
49 | # GCC has the option -mieee. | |
50 | CPPFLAGS="$CPPFLAGS -mieee" | |
51 | fi | |
52 | ;; | |
53 | esac | |
54 | ]) |