--- /dev/null
+/*\r
+ LUFA Library\r
+ Copyright (C) Dean Camera, 2011.\r
+\r
+ dean [at] fourwalledcubicle [dot] com\r
+ www.lufa-lib.org\r
+*/\r
+\r
+/*\r
+ Copyright 2011 Dean Camera (dean [at] fourwalledcubicle [dot] com)\r
+\r
+ Permission to use, copy, modify, distribute, and sell this\r
+ software and its documentation for any purpose is hereby granted\r
+ without fee, provided that the above copyright notice appear in\r
+ all copies and that both that the copyright notice and this\r
+ permission notice and warranty disclaimer appear in supporting\r
+ documentation, and that the name of the author not be used in\r
+ advertising or publicity pertaining to distribution of the\r
+ software without specific, written prior permission.\r
+\r
+ The author disclaim all warranties with regard to this\r
+ software, including all implied warranties of merchantability\r
+ and fitness. In no event shall the author be liable for any\r
+ special, indirect or consequential damages or any damages\r
+ whatsoever resulting from loss of use, data or profits, whether\r
+ in an action of contract, negligence or other tortious action,\r
+ arising out of or in connection with the use or performance of\r
+ this software.\r
+*/\r
+\r
+/** \file\r
+ * \brief Compiler specific macros for code optimization and correctness.\r
+ *\r
+ * \copydetails Group_CompilerSpecific\r
+ *\r
+ * \note Do not include this file directly, rather include the Common.h header file instead to gain this file's\r
+ * functionality.\r
+ */\r
+\r
+/** \ingroup Group_Common\r
+ * \defgroup Group_CompilerSpecific Compiler Specific Macros\r
+ * \brief Compiler specific macros for code optimization and correctness.\r
+ *\r
+ * Compiler specific macros to expose certain compiler features which may increase the level of code optimization\r
+ * for a specific compiler, or correct certain issues that may be present such as memory barriers for use in conjunction\r
+ * with atomic variable access. \r
+ *\r
+ * Where possible, on alternative compilers, these macros will either have no effect, or default to returning a sane value\r
+ * so that they can be used in existing code without the need for extra compiler checks in the user application code.\r
+ *\r
+ * @{\r
+ */\r
+\r
+#ifndef __LUFA_COMPILERSPEC_H__\r
+#define __LUFA_COMPILERSPEC_H__\r
+\r
+ /* Preprocessor Checks: */\r
+ #if !defined(__INCLUDE_FROM_COMMON_H)\r
+ #error Do not include this file directly. Include LUFA/Common/Common.h instead to gain this functionality.\r
+ #endif\r
+\r
+ /* Public Interface - May be used in end-application: */\r
+ /* Macros: */\r
+ #if defined(__GNUC__) || defined(__DOXYGEN__)\r
+ /** Forces GCC to use pointer indirection (via the device's pointer register pairs) when accessing the given\r
+ * struct pointer. In some cases GCC will emit non-optimal assembly code when accessing a structure through\r
+ * a pointer, resulting in a larger binary. When this macro is used on a (non \c const) structure pointer before\r
+ * use, it will force GCC to use pointer indirection on the elements rather than direct store and load\r
+ * instructions.\r
+ *\r
+ * \param[in, out] StructPtr Pointer to a structure which is to be forced into indirect access mode.\r
+ */\r
+ #define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr))\r
+\r
+ /** Forces GCC to create a memory barrier, ensuring that memory accesses are not reordered past the barrier point.\r
+ * This can be used before ordering-critical operations, to ensure that the compiler does not re-order the resulting\r
+ * assembly output in an unexpected manner on sections of code that are ordering-specific.\r
+ */\r
+ #define GCC_MEMORY_BARRIER() __asm__ __volatile__("" ::: "memory");\r
+ \r
+ /** Evaluates to boolean true if the specified value can be determined at compile time to be a constant value\r
+ * when compiling under GCC.\r
+ *\r
+ * \param[in] x Value to check compile time constantness of.\r
+ *\r
+ * \return Boolean true if the given value is known to be a compile time constant.\r
+ */\r
+ #define GCC_IS_COMPILE_CONST(x) __builtin_constant_p(x)\r
+ #else\r
+ #define GCC_FORCE_POINTER_ACCESS(StructPtr)\r
+ #define GCC_MEMORY_BARRIER()\r
+ #define GCC_IS_COMPILE_CONST(x) 0\r
+ #endif\r
+\r
+#endif\r
+\r
projects / pub / lufa.git / blobdiff