1# fpieee.m4 serial 2 2dnl Copyright (C) 2007, 2009-2012 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7dnl IEEE 754 standardized three items: 8dnl - The formats of single-float and double-float - nowadays commonly 9dnl available as 'float' and 'double' in C and C++. 10dnl No autoconf test needed. 11dnl - The overflow and division by zero behaviour: The result are values 12dnl '±Inf' and 'NaN', rather than exceptions as it was before. 13dnl This file provides an autoconf macro for ensuring this behaviour of 14dnl floating-point operations. 15dnl - A set of conditions (overflow, underflow, inexact, etc.) which can 16dnl be configured to trigger an exception. 17dnl This cannot be done in a portable way: it depends on the compiler, 18dnl libc, kernel, and CPU. No autoconf macro is provided for this. 19 20dnl Ensure non-trapping behaviour of floating-point overflow and 21dnl floating-point division by zero. 22dnl (For integer overflow, see gcc's -ftrapv option; for integer division by 23dnl zero, see the autoconf macro in intdiv0.m4.) 24 25AC_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