Vc package added (version 0.6.79-dev)

[u/mrichter/AliRoot.git] / Vc / include / Vc / common / support.h

diff --git a/Vc/include/Vc/common/support.h b/Vc/include/Vc/common/support.h
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+++ b/Vc/include/Vc/common/support.h
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+/*  This file is part of the Vc library.
+
+    Copyright (C) 2010-2012 Matthias Kretz <kretz@kde.org>
+
+    Vc is free software: 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, either version 3 of
+    the License, or (at your option) any later version.
+
+    Vc is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with Vc.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#ifndef VC_COMMON_SUPPORT_H
+#define VC_COMMON_SUPPORT_H
+
+#ifndef VC_GLOBAL_H
+#error "Vc/global.h must be included first!"
+#endif
+
+namespace Vc
+{
+
+/**
+ * \ingroup Utilities
+ *
+ * Tests whether the given implementation is supported by the system the code is executing on.
+ *
+ * \return \c true if the OS and hardware support execution of instructions defined by \p impl.
+ * \return \c false otherwise
+ *
+ * \param impl The SIMD target to test for.
+ */
+bool isImplementationSupported(Vc::Implementation impl);
+
+#ifndef VC_COMPILE_LIB
+/**
+ * \ingroup Utilities
+ *
+ * Tests that the CPU and Operating System support the vector unit which was compiled for. This
+ * function should be called before any other Vc functionality is used. It checks whether the program
+ * will work. If this function returns \c false then the program should exit with a useful error
+ * message before the OS has to kill it because of an invalid instruction exception.
+ *
+ * If the program continues and makes use of any vector features not supported by
+ * hard- or software then the program will crash.
+ *
+ * Example:
+ * \code
+ * int main()
+ * {
+ *   if (!Vc::currentImplementationSupported()) {
+ *     std::cerr << "CPU or OS requirements not met for the compiled in vector unit!\n";
+ *     exit -1;
+ *   }
+ *   ...
+ * }
+ * \endcode
+ *
+ * \return \c true if the OS and hardware support execution of the currently selected SIMD
+ *                 instructions.
+ * \return \c false otherwise
+ */
+#ifdef VC_GCC
+    __attribute__((target("no-sse2,no-avx")))
+#endif
+bool currentImplementationSupported()
+{
+    return isImplementationSupported(
+#ifdef VC_USE_VEX_CODING
+            // everything will use VEX coding, so the system has to support AVX even if VC_IMPL_AVX
+            // is not set
+            AVXImpl
+#else
+            VC_IMPL
+#endif
+#ifdef VC_IMPL_XOP
+            ) && isImplementationSupported(XopImpl
+#endif
+#ifdef VC_IMPL_FMA4
+            ) && isImplementationSupported(Fma4Impl
+#endif
+            );
+}
+#endif // VC_COMPILE_LIB
+
+} // namespace Vc
+
+#endif // VC_COMMON_SUPPORT_H