From b1528a12565c214f34e4e26b5032980780ae4d24 Mon Sep 17 00:00:00 2001 From: Dean Camera Date: Sun, 13 Mar 2011 05:54:13 +0000 Subject: [PATCH] Move out endianness management macros into a new common Endianness.h header. Fix Doxygen documentation, broken due to the added ATTR_PACKED attribute on some structs breaking the Doxygen parser. --- LUFA.pnproj | 2 +- LUFA/Common/Attributes.h | 4 +- LUFA/Common/Common.h | 163 +------------- LUFA/Common/Endianess.h | 462 +++++++++++++++++++++++++++++++++++++++ LUFA/Doxygen.conf | 3 +- 5 files changed, 480 insertions(+), 154 deletions(-) create mode 100644 LUFA/Common/Endianess.h diff --git a/LUFA.pnproj b/LUFA.pnproj index 96065e72fa..a06bd0b91d 100644 --- a/LUFA.pnproj +++ b/LUFA.pnproj @@ -1 +1 @@ - \ No newline at end of file + \ No newline at end of file diff --git a/LUFA/Common/Attributes.h b/LUFA/Common/Attributes.h index 62ce9f29e4..53cfb6df1a 100644 --- a/LUFA/Common/Attributes.h +++ b/LUFA/Common/Attributes.h @@ -134,7 +134,9 @@ */ #define ATTR_ALIAS(Func) __attribute__ ((alias( #Func ))) - /** Marks a variable or struct element for packing into the smallest space available. */ + /** Marks a variable or struct element for packing into the smallest space available, omitting any + * alignment bytes usually added between fields to optimize field accesses. + */ #define ATTR_PACKED __attribute__ ((packed)) /** Indicates the minimum alignment in bytes for a variable or struct element. diff --git a/LUFA/Common/Common.h b/LUFA/Common/Common.h index da4b1ddc84..e24906d4d7 100644 --- a/LUFA/Common/Common.h +++ b/LUFA/Common/Common.h @@ -49,12 +49,6 @@ * Macros to aid debugging of a user application. */ -/** \defgroup Group_BitManip Endian and Bit Macros - * \brief Convenience macros to aid in bit manipulations and endianness transforms. - * - * Functions for swapping endianness and reversing bit orders of data. - */ - #ifndef __LUFA_COMMON_H__ #define __LUFA_COMMON_H__ @@ -87,47 +81,13 @@ #include typedef uint8_t uint_reg_t; - - #define le16_to_cpu(x) x - #define le32_to_cpu(x) x - #define be16_to_cpu(x) SwapEndian_16(x) - #define be32_to_cpu(x) SwapEndian_32(x) - #define cpu_to_le16(x) x - #define cpu_to_le32(x) x - #define cpu_to_be16(x) SwapEndian_16(x) - #define cpu_to_be32(x) SwapEndian_32(x) - #define LE16_TO_CPU(x) x - #define LE32_TO_CPU(x) x - #define BE16_TO_CPU(x) SWAPENDIAN_16(x) - #define BE32_TO_CPU(x) SWAPENDIAN_32(x) - #define CPU_TO_LE16(x) x - #define CPU_TO_LE32(x) x - #define CPU_TO_BE16(x) SWAPENDIAN_16(x) - #define CPU_TO_BE32(x) SWAPENDIAN_32(x) - + + #define ARCH_LITTLE_ENDIAN + #include "Endianness.h" #elif (ARCH == ARCH_UC3B) #include - typedef uint32_t uint_reg_t; - - // TODO - #define le16_to_cpu(x) SwapEndian_16(x) - #define le32_to_cpu(x) SwapEndian_32(x) - #define be16_to_cpu(x) x - #define be32_to_cpu(x) x - #define cpu_to_le16(x) SwapEndian_16(x) - #define cpu_to_le32(x) SwapEndian_32(x) - #define cpu_to_be16(x) x - #define cpu_to_be32(x) x - #define LE16_TO_CPU(x) SWAPENDIAN_16(x) - #define LE32_TO_CPU(x) SWAPENDIAN_32(x) - #define BE16_TO_CPU(x) x - #define BE32_TO_CPU(x) x - #define CPU_TO_LE16(x) SWAPENDIAN_16(x) - #define CPU_TO_LE32(x) SWAPENDIAN_32(x) - #define CPU_TO_BE16(x) x - #define CPU_TO_BE32(x) x - + // === TODO: Find abstracted way to handle these === #define ISR(Name) void Name (void) __attribute__((__interrupt__)); void Name (void) #define EEMEM #define PROGMEM const @@ -140,8 +100,15 @@ #define _delay_ms(x) #define memcmp_P(...) memcmp(__VA_ARGS__) #define memcpy_P(...) memcpy(__VA_ARGS__) - #define USE_RAM_DESCRIPTORS + // ================================================== + + typedef uint32_t uint_reg_t; + + #define ARCH_BIG_ENDIAN + #include "Endianness.h" + #else + #error Unknown device architecture specified. #endif /* Public Interface - May be used in end-application: */ @@ -251,35 +218,10 @@ */ #define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr)) - /** Swaps the byte ordering of a 16-bit value at compile time. Do not use this macro for swapping byte orderings - * of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used - * inside struct or other variable initializers outside of a function, something that is not possible with the - * inline function variant. - * - * \param[in] x 16-bit value whose byte ordering is to be swapped. - * - * \return Input value with the byte ordering reversed. - */ - #define SWAPENDIAN_16(x) ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8)) - - /** Swaps the byte ordering of a 32-bit value at compile time. Do not use this macro for swapping byte orderings - * of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used - * inside struct or other variable initializers outside of a function, something that is not possible with the - * inline function variant. - * - * \param[in] x 32-bit value whose byte ordering is to be swapped. - * - * \return Input value with the byte ordering reversed. - */ - #define SWAPENDIAN_32(x) ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \ - (((x) & 0x0000FF00UL) << 8UL) | (((x) & 0x000000FFUL) << 24UL)) - /* Inline Functions: */ /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1, * etc. * - * \ingroup Group_BitManip - * * \param[in] Byte Byte of data whose bits are to be reversed. */ static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST; @@ -292,87 +234,6 @@ return Byte; } - /** Function to reverse the byte ordering of the individual bytes in a 16 bit number. - * - * \ingroup Group_BitManip - * - * \param[in] Word Word of data whose bytes are to be swapped. - */ - static inline uint16_t SwapEndian_16(const uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST; - static inline uint16_t SwapEndian_16(const uint16_t Word) - { - uint8_t Temp; - - union - { - uint16_t Word; - uint8_t Bytes[2]; - } Data; - - Data.Word = Word; - - Temp = Data.Bytes[0]; - Data.Bytes[0] = Data.Bytes[1]; - Data.Bytes[1] = Temp; - - return Data.Word; - } - - /** Function to reverse the byte ordering of the individual bytes in a 32 bit number. - * - * \ingroup Group_BitManip - * - * \param[in] DWord Double word of data whose bytes are to be swapped. - */ - static inline uint32_t SwapEndian_32(const uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST; - static inline uint32_t SwapEndian_32(const uint32_t DWord) - { - uint8_t Temp; - - union - { - uint32_t DWord; - uint8_t Bytes[4]; - } Data; - - Data.DWord = DWord; - - Temp = Data.Bytes[0]; - Data.Bytes[0] = Data.Bytes[3]; - Data.Bytes[3] = Temp; - - Temp = Data.Bytes[1]; - Data.Bytes[1] = Data.Bytes[2]; - Data.Bytes[2] = Temp; - - return Data.DWord; - } - - /** Function to reverse the byte ordering of the individual bytes in a n byte number. - * - * \ingroup Group_BitManip - * - * \param[in,out] Data Pointer to a number containing an even number of bytes to be reversed. - * \param[in] Bytes Length of the data in bytes. - */ - static inline void SwapEndian_n(void* Data, - uint8_t Bytes) ATTR_NON_NULL_PTR_ARG(1); - static inline void SwapEndian_n(void* Data, - uint8_t Bytes) - { - uint8_t* CurrDataPos = (uint8_t*)Data; - - while (Bytes > 1) - { - uint8_t Temp = *CurrDataPos; - *CurrDataPos = *(CurrDataPos + Bytes - 1); - *(CurrDataPos + Bytes - 1) = Temp; - - CurrDataPos++; - Bytes -= 2; - } - } - #endif /** @} */ diff --git a/LUFA/Common/Endianess.h b/LUFA/Common/Endianess.h new file mode 100644 index 0000000000..d7f73ca69f --- /dev/null +++ b/LUFA/Common/Endianess.h @@ -0,0 +1,462 @@ +/* + LUFA Library + Copyright (C) Dean Camera, 2011. + + dean [at] fourwalledcubicle [dot] com + www.lufa-lib.org +*/ + +/* + Copyright 2011 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 Endianness and Byte Ordering macros and functions. + * + * \copydetails Group_Endianness + */ + +/** \ingroup Group_Endianness + * \defgroup Group_ByteSwapping Byte Reordering + * \brief Macros and functions for forced byte reordering. + */ + +/** \ingroup Group_Endianness + * \defgroup Group_EndianConversion Endianness Conversion + * \brief Macros and functions for automatic endianness conversion. + */ + +/** \ingroup Group_Common + * \defgroup Group_Endianness Endianness and Byte Ordering + * \brief Convenience macros and functions relating to byte (re-)ordering + * + * Common library convenience macros and functions relating to byte (re-)ordering. + * + * @{ + */ + +#ifndef __LUFA_ENDIANNESS_H__ +#define __LUFA_ENDIANNESS_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: */ + /** Swaps the byte ordering of a 16-bit value at compile-time. Do not use this macro for swapping byte orderings + * of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used + * inside struct or other variable initializers outside of a function, something that is not possible with the + * inline function variant. + * + * \ingroup Group_ByteSwapping + * + * \param[in] x 16-bit value whose byte ordering is to be swapped. + * + * \return Input value with the byte ordering reversed. + */ + #define SWAPENDIAN_16(x) ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8)) + + /** Swaps the byte ordering of a 32-bit value at compile-time. Do not use this macro for swapping byte orderings + * of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used + * inside struct or other variable initializers outside of a function, something that is not possible with the + * inline function variant. + * + * \ingroup Group_ByteSwapping + * + * \param[in] x 32-bit value whose byte ordering is to be swapped. + * + * \return Input value with the byte ordering reversed. + */ + #define SWAPENDIAN_32(x) ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \ + (((x) & 0x0000FF00UL) << 8UL) | (((x) & 0x000000FFUL) << 24UL)) + + #if defined(ARCH_BIG_ENDIAN) && !defined(le16_to_cpu) + #define le16_to_cpu(x) SwapEndian_16(x) + #define le32_to_cpu(x) SwapEndian_32(x) + #define be16_to_cpu(x) x + #define be32_to_cpu(x) x + #define cpu_to_le16(x) SwapEndian_16(x) + #define cpu_to_le32(x) SwapEndian_32(x) + #define cpu_to_be16(x) x + #define cpu_to_be32(x) x + #define LE16_TO_CPU(x) SWAPENDIAN_16(x) + #define LE32_TO_CPU(x) SWAPENDIAN_32(x) + #define BE16_TO_CPU(x) x + #define BE32_TO_CPU(x) x + #define CPU_TO_LE16(x) SWAPENDIAN_16(x) + #define CPU_TO_LE32(x) SWAPENDIAN_32(x) + #define CPU_TO_BE16(x) x + #define CPU_TO_BE32(x) x + #elif !defined(le16_to_cpu) + /** \name Run-time endianness conversion */ + //@{ + + /** Performs a conversion between a Little Endian encoded 16-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref LE16_TO_CPU instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define le16_to_cpu(x) x + + /** Performs a conversion between a Little Endian encoded 32-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref LE32_TO_CPU instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define le32_to_cpu(x) x + + /** Performs a conversion between a Big Endian encoded 16-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref BE16_TO_CPU instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define be16_to_cpu(x) SwapEndian_16(x) + + /** Performs a conversion between a Big Endian encoded 32-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref BE32_TO_CPU instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define be32_to_cpu(x) SwapEndian_32(x) + + /** Performs a conversion on a natively encoded 16-bit piece of data to ensure that it + * is in Little Endian format regardless of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref CPU_TO_LE16 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define cpu_to_le16(x) x + + /** Performs a conversion on a natively encoded 32-bit piece of data to ensure that it + * is in Little Endian format regardless of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref CPU_TO_LE32 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define cpu_to_le32(x) x + + /** Performs a conversion on a natively encoded 16-bit piece of data to ensure that it + * is in Big Endian format regardless of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref CPU_TO_BE16 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define cpu_to_be16(x) SwapEndian_16(x) + + /** Performs a conversion on a natively encoded 32-bit piece of data to ensure that it + * is in Big Endian format regardless of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for run-time conversion of data - for compile-time endianness + * conversion, use \ref CPU_TO_BE32 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define cpu_to_be32(x) SwapEndian_32(x) + + //@} + + /** \name Compile-time endianness conversion */ + //@{ + + /** Performs a conversion between a Little Endian encoded 16-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run time endianness + * conversion, use \ref le16_to_cpu instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define LE16_TO_CPU(x) x + + /** Performs a conversion between a Little Endian encoded 32-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run time endianness + * conversion, use \ref le32_to_cpu instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define LE32_TO_CPU(x) x + + /** Performs a conversion between a Big Endian encoded 16-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref be16_to_cpu instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define BE16_TO_CPU(x) SWAPENDIAN_16(x) + + /** Performs a conversion between a Big Endian encoded 32-bit piece of data and the + * Endianness of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref be32_to_cpu instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define BE32_TO_CPU(x) SWAPENDIAN_32(x) + + /** Performs a conversion on a natively encoded 16-bit piece of data to ensure that it + * is in Little Endian format regardless of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref cpu_to_le16 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define CPU_TO_LE16(x) x + + /** Performs a conversion on a natively encoded 32-bit piece of data to ensure that it + * is in Little Endian format regardless of the currently selected CPU architecture. + * + * On little endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref cpu_to_le32 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define CPU_TO_LE32(x) x + + /** Performs a conversion on a natively encoded 16-bit piece of data to ensure that it + * is in Big Endian format regardless of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref cpu_to_be16 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define CPU_TO_BE16(x) SWAPENDIAN_16(x) + + /** Performs a conversion on a natively encoded 32-bit piece of data to ensure that it + * is in Big Endian format regardless of the currently selected CPU architecture. + * + * On big endian architectures, this macro does nothing. + * + * \note This macro is designed for compile-time conversion of data - for run-time endianness + * conversion, use \ref cpu_to_be32 instead. + * + * \ingroup Group_EndianConversion + * + * \param[in] x Data to perform the endianness conversion on. + * + * \return Endian corrected version of the input value. + */ + #define CPU_TO_BE32(x) SWAPENDIAN_32(x) + + //! @} + #endif + + /* Inline Functions: */ + /** Function to reverse the byte ordering of the individual bytes in a 16 bit value. + * + * \ingroup Group_ByteSwapping + * + * \param[in] Word Word of data whose bytes are to be swapped. + */ + static inline uint16_t SwapEndian_16(const uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST; + static inline uint16_t SwapEndian_16(const uint16_t Word) + { + uint8_t Temp; + + union + { + uint16_t Word; + uint8_t Bytes[2]; + } Data; + + Data.Word = Word; + + Temp = Data.Bytes[0]; + Data.Bytes[0] = Data.Bytes[1]; + Data.Bytes[1] = Temp; + + return Data.Word; + } + + /** Function to reverse the byte ordering of the individual bytes in a 32 bit value. + * + * \ingroup Group_ByteSwapping + * + * \param[in] DWord Double word of data whose bytes are to be swapped. + */ + static inline uint32_t SwapEndian_32(const uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST; + static inline uint32_t SwapEndian_32(const uint32_t DWord) + { + uint8_t Temp; + + union + { + uint32_t DWord; + uint8_t Bytes[4]; + } Data; + + Data.DWord = DWord; + + Temp = Data.Bytes[0]; + Data.Bytes[0] = Data.Bytes[3]; + Data.Bytes[3] = Temp; + + Temp = Data.Bytes[1]; + Data.Bytes[1] = Data.Bytes[2]; + Data.Bytes[2] = Temp; + + return Data.DWord; + } + + /** Function to reverse the byte ordering of the individual bytes in a n byte value. + * + * \ingroup Group_ByteSwapping + * + * \param[in,out] Data Pointer to a number containing an even number of bytes to be reversed. + * \param[in] Bytes Length of the data in bytes. + */ + static inline void SwapEndian_n(void* Data, + uint8_t Bytes) ATTR_NON_NULL_PTR_ARG(1); + static inline void SwapEndian_n(void* Data, + uint8_t Bytes) + { + uint8_t* CurrDataPos = (uint8_t*)Data; + + while (Bytes > 1) + { + uint8_t Temp = *CurrDataPos; + *CurrDataPos = *(CurrDataPos + Bytes - 1); + *(CurrDataPos + Bytes - 1) = Temp; + + CurrDataPos++; + Bytes -= 2; + } + } + +#endif + +/** @} */ diff --git a/LUFA/Doxygen.conf b/LUFA/Doxygen.conf index 624ff928ac..dadb864fe3 100644 --- a/LUFA/Doxygen.conf +++ b/LUFA/Doxygen.conf @@ -1426,7 +1426,8 @@ INCLUDE_FILE_PATTERNS = PREDEFINED = __DOXYGEN__ \ PROGMEM \ - EEMEM + EEMEM \ + ATTR_PACKED # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then # this tag can be used to specify a list of macro names that should be expanded.