/* * Copyright (C) 2011, Google Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef DenormalDisabler_h #define DenormalDisabler_h namespace WebCore { // Deal with denormals. They can very seriously impact performance on x86. #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) class DenormalDisabler { public: DenormalDisabler() { m_savedCSR = getCSR(); setCSR(m_savedCSR | 0x8040); } ~DenormalDisabler() { setCSR(m_savedCSR); } private: inline int getCSR() { int result; asm volatile("stmxcsr %0" : "=m" (result)); return result; } inline void setCSR(int a) { int temp = a; asm volatile("ldmxcsr %0" : : "m" (temp)); } int m_savedCSR; }; #else // FIXME: add implementations for other architectures and compilers such as Visual Studio. class DenormalDisabler { public: DenormalDisabler() { } }; #endif } // WebCore #endif // DenormalDisabler_h