98 lines
4.2 KiB
C
98 lines
4.2 KiB
C
/*
|
|
LUFA Library
|
|
Copyright (C) Dean Camera, 2012.
|
|
|
|
dean [at] fourwalledcubicle [dot] com
|
|
www.lufa-lib.org
|
|
*/
|
|
|
|
/*
|
|
Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
|
|
|
|
Permission to use, copy, modify, distribute, and sell this
|
|
software and its documentation for any purpose is hereby granted
|
|
without fee, provided that the above copyright notice appear in
|
|
all copies and that both that the copyright notice and this
|
|
permission notice and warranty disclaimer appear in supporting
|
|
documentation, and that the name of the author not be used in
|
|
advertising or publicity pertaining to distribution of the
|
|
software without specific, written prior permission.
|
|
|
|
The author disclaim all warranties with regard to this
|
|
software, including all implied warranties of merchantability
|
|
and fitness. In no event shall the author be liable for any
|
|
special, indirect or consequential damages or any damages
|
|
whatsoever resulting from loss of use, data or profits, whether
|
|
in an action of contract, negligence or other tortious action,
|
|
arising out of or in connection with the use or performance of
|
|
this software.
|
|
*/
|
|
|
|
/** \file
|
|
* \brief Compiler specific definitions for code optimization and correctness.
|
|
*
|
|
* \copydetails Group_CompilerSpecific
|
|
*
|
|
* \note Do not include this file directly, rather include the Common.h header file instead to gain this file's
|
|
* functionality.
|
|
*/
|
|
|
|
/** \ingroup Group_Common
|
|
* \defgroup Group_CompilerSpecific Compiler Specific Definitions
|
|
* \brief Compiler specific definitions for code optimization and correctness.
|
|
*
|
|
* Compiler specific definitions to expose certain compiler features which may increase the level of code optimization
|
|
* for a specific compiler, or correct certain issues that may be present such as memory barriers for use in conjunction
|
|
* with atomic variable access.
|
|
*
|
|
* Where possible, on alternative compilers, these macros will either have no effect, or default to returning a sane value
|
|
* so that they can be used in existing code without the need for extra compiler checks in the user application code.
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
#ifndef __LUFA_COMPILERSPEC_H__
|
|
#define __LUFA_COMPILERSPEC_H__
|
|
|
|
/* Preprocessor Checks: */
|
|
#if !defined(__INCLUDE_FROM_COMMON_H)
|
|
#error Do not include this file directly. Include LUFA/Common/Common.h instead to gain this functionality.
|
|
#endif
|
|
|
|
/* Public Interface - May be used in end-application: */
|
|
/* Macros: */
|
|
#if defined(__GNUC__) || defined(__DOXYGEN__)
|
|
/** Forces GCC to use pointer indirection (via the device's pointer register pairs) when accessing the given
|
|
* struct pointer. In some cases GCC will emit non-optimal assembly code when accessing a structure through
|
|
* a pointer, resulting in a larger binary. When this macro is used on a (non \c const) structure pointer before
|
|
* use, it will force GCC to use pointer indirection on the elements rather than direct store and load
|
|
* instructions.
|
|
*
|
|
* \param[in, out] StructPtr Pointer to a structure which is to be forced into indirect access mode.
|
|
*/
|
|
#define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr))
|
|
|
|
/** Forces GCC to create a memory barrier, ensuring that memory accesses are not reordered past the barrier point.
|
|
* This can be used before ordering-critical operations, to ensure that the compiler does not re-order the resulting
|
|
* assembly output in an unexpected manner on sections of code that are ordering-specific.
|
|
*/
|
|
#define GCC_MEMORY_BARRIER() __asm__ __volatile__("" ::: "memory");
|
|
|
|
/** Determines if the specified value can be determined at compile-time to be a constant value when compiling under GCC.
|
|
*
|
|
* \param[in] x Value to check compile-time constantness of.
|
|
*
|
|
* \return Boolean true if the given value is known to be a compile time constant, false otherwise.
|
|
*/
|
|
#define GCC_IS_COMPILE_CONST(x) __builtin_constant_p(x)
|
|
#else
|
|
#define GCC_FORCE_POINTER_ACCESS(StructPtr)
|
|
#define GCC_MEMORY_BARRIER()
|
|
#define GCC_IS_COMPILE_CONST(x) 0
|
|
#endif
|
|
|
|
#endif
|
|
|
|
/** @} */
|
|
|