Add functions for checking underflow

Number_types/include/CGAL/FPU_extension.h

@@ -0,0 +1,68 @@
+// Copyright (c) 2010-2011  GeometryFactory Sarl (France)
+//
+// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation; version 2.1 of the License.
+// See the file LICENSE.LGPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+//
+// Author(s)     : Laurent Rineau
+
+
+// The main goal of FPU.h is to define functions or macros to modify the
+// control word of the FPU, to:
+//   - set the precision to 53 bits of mantissa,
+//   - get/set the rounding mode.
+// 
+// The goal of FPU_extension.h is to define inline functions similar to
+// feclearexcept and fetestexcept of C99.
+//
+// For the moment, only i386 and x64 processors are supported, with MSVC,
+// gcc, or the Intel compiler suite. Otherwise, the non-inline functions of
+// C99 are used.
+
+#ifndef CGAL_FPU_EXTENSION_H
+#define CGAL_FPU_EXTENSION_H
+
+#if __i386__ && !defined __PGI && !defined __SUNPRO_CC
+#  ifdef CGAL_SAFE_SSE2
+#    include <CGAL/FPU_gcc_i386_sse2.h>
+#  else
+#    include <CGAL/FPU_gcc_i386.h>
+#  endif
+#elif defined _MSC_VER
+#  include <CGAL/FPU_msvc.h>
+#else 
+
+// generic functions, using C99
+
+extern "C" {
+#  include <fenv.h>
+}
+
+namespace CGAL {
+
+inline int
+feclearexcept(int exceptions) {
+  return ::feclearexcept(exceptions);
+}
+
+inline int
+fetestexcept(int exceptions) {
+  return ::fetestexcept(exceptions);
+}
+
+} // end namespace CGAL
+
+#endif // use fenv
+
+#endif // CGAL_FPU_EXTENSION_H

Number_types/include/CGAL/FPU_gcc_i386.h

@@ -0,0 +1,41 @@
+// Copyright (c) 2010-2011  GeometryFactory Sarl (France)
+//
+// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation; version 2.1 of the License.
+// See the file LICENSE.LGPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+//
+// Author(s)     : Laurent Rineau
+
+extern "C" { 
+#include <fenv.h>
+}
+
+namespace CGAL {
+
+// brute-force replacement for C99 (which does not require an inline-function)
+inline int
+feclearexcept(int exceptions) {
+    // TODO: clear only given exceptions
+    asm volatile("fnclex");
+    return 0;
+}
+
+inline int
+fetestexcept(int exceptions) {
+    int status;
+    asm volatile("fnstsw %0" : "=m" (status));
+    return status & exceptions;
+}
+
+} // end namespace CGAL

Number_types/include/CGAL/FPU_gcc_i386_sse2.h

@@ -0,0 +1,44 @@
+// Copyright (c) 2010-2011  GeometryFactory Sarl (France)
+//
+// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation; version 2.1 of the License.
+// See the file LICENSE.LGPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+//
+// Author(s)     : Laurent Rineau
+
+extern "C" { 
+#include <fenv.h>
+}
+
+namespace CGAL {
+
+// replacement for C99
+
+inline int
+feclearexcept(int exceptions) {
+    int mxcsr;
+    asm volatile("stmxcsr %0" : "=m" (mxcsr) );
+    mxcsr &= ~exceptions;
+    asm volatile("ldmxcsr %0" : : "m" (mxcsr) );
+    return 0;
+}
+
+inline int
+fetestexcept(int exceptions) {
+    int status;
+    asm volatile("stmxcsr %0" : "=m" (status) );
+    return status & exceptions;
+}
+
+} // end namespace CGAL

Number_types/include/CGAL/FPU_msvc.h

@@ -0,0 +1,55 @@
+// Copyright (c) 2010-2011  GeometryFactory Sarl (France)
+//
+// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation; version 2.1 of the License.
+// See the file LICENSE.LGPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+//
+// Author(s)     : Laurent Rineau
+
+#include <cfloat>
+
+#ifndef FE_INVALID
+#  define FE_INEXACT     _EM_INEXACT
+#  define FE_UNDERFLOW   _EM_UNDERFLOW
+#  define FE_OVERFLOW    _EM_OVERFLOW
+#  define FE_DIVBYZERO   _EM_ZERODIVIDE
+#  define FE_INVALID     _EM_INVALID
+#endif
+
+namespace CGAL {
+
+// replacement for C99 functions
+
+inline int
+feclearexcept(int exceptions) {
+  _clearfp();
+  return 0;
+}
+
+inline int
+fetestexcept(int exceptions)
+{
+#if defined(_M_IX86) && _M_IX86_FP > 0
+  // On x86/x64 processors, when SSE is used.
+  unsigned int i1;
+  unsigned int i2;
+  _statusfp2(&i1, &i2);
+  return (i1 & exceptions) | (i2 & exceptions);
+#else
+  // On x86 processors without SSE, or on other processors supported by MSVC
+  return _statusfp() & exceptions;
+#endif
+}
+
+} // end namespace CGAL