1 # fpieee.m4 serial 2 2 dnl Copyright (C) 2007, 2009-2012 Free Software Foundation, Inc. 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 "$host_cpu" in 33 alpha*) 34 # On Alpha systems, a compiler option provides the behaviour. 35 # See the ieee(3) manual page, also available at 36 # <http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51B_HTML/MAN/MAN3/0600____.HTM> 37 if test -n "$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 ]) 55
