src/common/tusb_compiler.h - third_party/github/hathach/tinyusb - Git at Google

 /*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
  * This file is part of the TinyUSB stack.
  */

 #pragma once

 #define TU_TOKEN(x)           x
 #define TU_STRING(x)          #x                  ///< stringify without expand
 #define TU_XSTRING(x)         TU_STRING(x)        ///< expand then stringify
 #define TU_STRCAT(a, b)       a##b                ///< concat without expand
 #define TU_STRCAT3(a, b, c)   a##b##c             ///< concat without expand
 #define TU_XSTRCAT(a, b)      TU_STRCAT(a, b)     ///< expand then concat
 #define TU_XSTRCAT3(a, b, c)  TU_STRCAT3(a, b, c) ///< expand then concat 3 tokens

 #define TU_INCLUDE_PATH(_dir,_file) TU_XSTRING( TU_TOKEN(_dir)TU_TOKEN(_file) )

 #if defined __COUNTER__ && __COUNTER__ != __COUNTER__
   #define TU_COUNTER __COUNTER__
 #else
   #define TU_COUNTER __LINE__
 #endif

 // Compile-time Assert
 #if defined (__cplusplus) && __cplusplus >= 201103L
   #define TU_VERIFY_STATIC   static_assert
 #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
   #define TU_VERIFY_STATIC   _Static_assert
 #elif defined(__CCRX__)
   #define TU_VERIFY_STATIC(const_expr, _mess) typedef char TU_XSTRCAT(_verify_static_, TU_COUNTER)[(const_expr) ? 1 : 0];
 #else
   #define TU_VERIFY_STATIC(const_expr, _mess) enum { TU_XSTRCAT(_verify_static_, TU_COUNTER) = 1/(!!(const_expr)) }
 #endif

 /* --------------------- Fuzzing types -------------------------------------- */
 #ifdef _FUZZ
   #define tu_static static __thread
 #else
   #define tu_static static
 #endif

 // for declaration of reserved field, make use of TU_COUNTER
 #define TU_RESERVED           TU_XSTRCAT(reserved, TU_COUNTER)

 #define TU_LITTLE_ENDIAN (0x12u)
 #define TU_BIG_ENDIAN (0x21u)

 /*------------------------------------------------------------------*/
 /* Count number of arguments of __VA_ARGS__
  * - reference www.stackoverflow.com/questions/2124339/c-preprocessor-va-args-number-of-arguments
  * - TU_GET_NTH_ARG() takes args >= N (64) but only expand to Nth one (64th)
  * - TU_NARG_RSEQ_N() is reverse sequential to N to add padding to have
  * Nth position is the same as the number of arguments
  * - ##__VA_ARGS__ is used to deal with 0 paramerter (swallows comma)
  *------------------------------------------------------------------*/
 #if defined(__CCRX__)
 #define TU_ARGS_NUM(...)   TU_NARG_IMPL(_0, __VA_ARGS__, TU_NARG_RSEQ_N())
 #else
 #define TU_ARGS_NUM(...)   TU_NARG_IMPL(_0, ##__VA_ARGS__, TU_NARG_RSEQ_N())
 #endif

 #define TU_NARG_IMPL(...)      TU_GET_NTH_ARG(__VA_ARGS__)
 #define TU_GET_NTH_ARG( \
           _1, _2, _3, _4, _5, _6, _7, _8, _9,_10, \
          _11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
          _21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
          _31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
          _41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
          _51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
          _61,_62,_63,N,...) N
 #define TU_NARG_RSEQ_N() \
          62,61,60,                      \
          59,58,57,56,55,54,53,52,51,50, \
          49,48,47,46,45,44,43,42,41,40, \
          39,38,37,36,35,34,33,32,31,30, \
          29,28,27,26,25,24,23,22,21,20, \
          19,18,17,16,15,14,13,12,11,10, \
          9,8,7,6,5,4,3,2,1,0

 // Apply a macro X to each of the arguments with a separation/delimiter
 #define TU_ARGS_APPLY(_X, _s, ...)   TU_XSTRCAT(TU_ARGS_APPLY_, TU_ARGS_NUM(__VA_ARGS__))(_X, _s, __VA_ARGS__)

 #define TU_ARGS_APPLY_1(_X, _s, _a1)                                    _X(_a1)
 #define TU_ARGS_APPLY_2(_X, _s, _a1, _a2)                               _X(_a1) _s _X(_a2)
 #define TU_ARGS_APPLY_3(_X, _s, _a1, _a2, _a3)                          _X(_a1) _s TU_ARGS_APPLY_2(_X, _s, _a2, _a3)
 #define TU_ARGS_APPLY_4(_X, _s, _a1, _a2, _a3, _a4)                     _X(_a1) _s TU_ARGS_APPLY_3(_X, _s, _a2, _a3, _a4)
 #define TU_ARGS_APPLY_5(_X, _s, _a1, _a2, _a3, _a4, _a5)                _X(_a1) _s TU_ARGS_APPLY_4(_X, _s, _a2, _a3, _a4, _a5)
 #define TU_ARGS_APPLY_6(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6)           _X(_a1) _s TU_ARGS_APPLY_5(_X, _s, _a2, _a3, _a4, _a5, _a6)
 #define TU_ARGS_APPLY_7(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7)      _X(_a1) _s TU_ARGS_APPLY_6(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7)
 #define TU_ARGS_APPLY_8(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7, _a8) _X(_a1) _s TU_ARGS_APPLY_7(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7, _a8)

 // Apply a macro X to each of the arguments and expand the result with comma
 #define TU_ARGS_APPLY_EXPAND(_X, ...)   TU_XSTRCAT(TU_ARGS_APPLY_EXPAND_, TU_ARGS_NUM(__VA_ARGS__))(_X, __VA_ARGS__)

 #define TU_ARGS_APPLY_EXPAND_1(_X, _a1)                                    _X(_a1)
 #define TU_ARGS_APPLY_EXPAND_2(_X, _a1, _a2)                               _X(_a1), _X(_a2)
 #define TU_ARGS_APPLY_EXPAND_3(_X, _a1, _a2, _a3)                          _X(_a1), TU_ARGS_APPLY_EXPAND_2(_X, _a2, _a3)
 #define TU_ARGS_APPLY_EXPAND_4(_X, _a1, _a2, _a3, _a4)                     _X(_a1), TU_ARGS_APPLY_EXPAND_3(_X, _a2, _a3, _a4)
 #define TU_ARGS_APPLY_EXPAND_5(_X, _a1, _a2, _a3, _a4, _a5)                _X(_a1), TU_ARGS_APPLY_EXPAND_4(_X, _a2, _a3, _a4, _a5)
 #define TU_ARGS_APPLY_EXPAND_6(_X, _a1, _a2, _a3, _a4, _a5, _a6)           _X(_a1), TU_ARGS_APPLY_EXPAND_5(_X, _a2, _a3, _a4, _a5, _a6)
 #define TU_ARGS_APPLY_EXPAND_7(_X, _a1, _a2, _a3, _a4, _a5, _a6, _a7)      _X(_a1), TU_ARGS_APPLY_EXPAND_6(_X, _a2, _a3, _a4, _a5, _a6, _a7)
 #define TU_ARGS_APPLY_EXPAND_8(_X, _a1, _a2, _a3, _a4, _a5, _a6, _a7, _a8) _X(_a1), TU_ARGS_APPLY_EXPAND_7(_X, _a2, _a3, _a4, _a5, _a6, _a7, _a8)

 //--------------------------------------------------------------------+
 // Macro for function default arguments
 //--------------------------------------------------------------------+
 #define TU_GET_3RD_ARG(arg1, arg2, arg3, ...)        arg3

 // function expand with number of arguments
 #define TU_FUNC_OPTIONAL_ARG(func, ...)   TU_XSTRCAT(func##_arg, TU_ARGS_NUM(__VA_ARGS__))(__VA_ARGS__)

 //--------------------------------------------------------------------+
 // Compiler Attribute Abstraction
 //--------------------------------------------------------------------+
 #if defined(__GNUC__) || defined(__ICCARM__) || defined(__TI_COMPILER_VERSION__)
   #if defined(__ICCARM__)
     #include <intrinsics.h> // for builtin functions
   #endif

   #define TU_ATTR_ALIGNED(Bytes)    __attribute__((aligned(Bytes)))
   #define TU_ATTR_SECTION(sec_name) __attribute__((section(#sec_name)))
   #define TU_ATTR_PACKED            __attribute__((packed))
   #define TU_ATTR_WEAK              __attribute__((weak))
 // #define TU_ATTR_WEAK_ALIAS(f)         __attribute__ ((weak, alias(#f)))
   #ifndef TU_ATTR_ALWAYS_INLINE                                            // allow to override for debug
     #define TU_ATTR_ALWAYS_INLINE __attribute__((always_inline))
   #endif
   #define TU_ATTR_DEPRECATED(mess)      __attribute__ ((deprecated(mess))) // warn if function with this attribute is used
   #define TU_ATTR_UNUSED                __attribute__ ((unused))           // Function/Variable is meant to be possibly unused
   #define TU_ATTR_USED                  __attribute__ ((used))             // Function/Variable is meant to be used

   #define TU_ATTR_PACKED_BEGIN
   #define TU_ATTR_PACKED_END
   #define TU_ATTR_BIT_FIELD_ORDER_BEGIN
   #define TU_ATTR_BIT_FIELD_ORDER_END

   #if (defined(__has_attribute) && __has_attribute(__fallthrough__)) || defined(__TI_COMPILER_VERSION__)
     #define TU_ATTR_FALLTHROUGH __attribute__((fallthrough))
   #else
     #define TU_ATTR_FALLTHROUGH     \
       do {                          \
       } while (0) /* fallthrough */
   #endif

 // Endian conversion use well-known host to network (big endian) naming
 // For TI ARM compiler, __BYTE_ORDER__ is not defined for MSP430 but still LE
   #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ || defined(__MSP430__)
     #define TU_BYTE_ORDER TU_LITTLE_ENDIAN
   #else
     #define TU_BYTE_ORDER TU_BIG_ENDIAN
   #endif

   // Unfortunately XC16 doesn't provide builtins for 32bit endian conversion
   #if defined(__XC16)
     #define TU_BSWAP16(u16) (__builtin_swap(u16))
     #define TU_BSWAP32(u32) ((((u32) & 0xff000000) >> 24) |  \
                             (((u32) & 0x00ff0000) >> 8)  |  \
                             (((u32) & 0x0000ff00) << 8)  |  \
                             (((u32) & 0x000000ff) << 24))
   #else
     #define TU_BSWAP16(u16) (__builtin_bswap16(u16))
     #define TU_BSWAP32(u32) (__builtin_bswap32(u32))
   #endif

   // List of obsolete callback function that is renamed and should not be defined.
   // Put it here since only gcc support this pragma
   #if !defined(__ARMCC_VERSION) && !defined(__ICCARM__)
     #pragma GCC poison tud_vendor_control_request_cb
   #endif

 #elif defined(__ICCARM__)
   #include <intrinsics.h>
   #define TU_ATTR_ALIGNED(Bytes)        __attribute__ ((aligned(Bytes)))
   #define TU_ATTR_SECTION(sec_name)     __attribute__ ((section(#sec_name)))
   #define TU_ATTR_PACKED                __attribute__ ((packed))
   #define TU_ATTR_WEAK                  __attribute__ ((weak))
   // #define TU_ATTR_WEAK_ALIAS(f)         __attribute__ ((weak, alias(#f)))
   #ifndef TU_ATTR_ALWAYS_INLINE // allow to override for debug
     #define TU_ATTR_ALWAYS_INLINE         __attribute__ ((always_inline))
   #endif
   #define TU_ATTR_DEPRECATED(mess)      __attribute__ ((deprecated(mess))) // warn if function with this attribute is used
   #define TU_ATTR_UNUSED                __attribute__ ((unused))           // Function/Variable is meant to be possibly unused
   #define TU_ATTR_USED                  __attribute__ ((used))             // Function/Variable is meant to be used
   #define TU_ATTR_FALLTHROUGH           do {} while (0)  /* fallthrough */

   #define TU_ATTR_PACKED_BEGIN
   #define TU_ATTR_PACKED_END
   #define TU_ATTR_BIT_FIELD_ORDER_BEGIN
   #define TU_ATTR_BIT_FIELD_ORDER_END

   // Endian conversion use well-known host to network (big endian) naming
   #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
     #define TU_BYTE_ORDER TU_LITTLE_ENDIAN
   #else
     #define TU_BYTE_ORDER TU_BIG_ENDIAN
   #endif

   #define TU_BSWAP16(u16) (__iar_builtin_REV16(u16))
   #define TU_BSWAP32(u32) (__iar_builtin_REV(u32))

 #elif defined(__CCRX__)
   #define TU_ATTR_ALIGNED(Bytes)
   #define TU_ATTR_SECTION(sec_name)
   #define TU_ATTR_PACKED
   #define TU_ATTR_WEAK
   // #define TU_ATTR_WEAK_ALIAS(f)
   #define TU_ATTR_ALWAYS_INLINE
   #define TU_ATTR_DEPRECATED(mess)
   #define TU_ATTR_UNUSED
   #define TU_ATTR_USED
   #define TU_ATTR_FALLTHROUGH           do {} while (0)  /* fallthrough */

   #define TU_ATTR_PACKED_BEGIN          _Pragma("pack")
   #define TU_ATTR_PACKED_END            _Pragma("packoption")
   #define TU_ATTR_BIT_FIELD_ORDER_BEGIN _Pragma("bit_order right")
   #define TU_ATTR_BIT_FIELD_ORDER_END   _Pragma("bit_order")

   // Endian conversion use well-known host to network (big endian) naming
   #if defined(__LIT)
     #define TU_BYTE_ORDER TU_LITTLE_ENDIAN
   #else
     #define TU_BYTE_ORDER TU_BIG_ENDIAN
   #endif

   #define TU_BSWAP16(u16) ((unsigned short)_builtin_revw((unsigned long)u16))
   #define TU_BSWAP32(u32) (_builtin_revl(u32))

 #else
   #error "Compiler attribute porting is required"
 #endif


 #if (TU_BYTE_ORDER == TU_LITTLE_ENDIAN)

   #define tu_htons(u16)  (TU_BSWAP16(u16))
   #define tu_ntohs(u16)  (TU_BSWAP16(u16))

   #define tu_htonl(u32)  (TU_BSWAP32(u32))
   #define tu_ntohl(u32)  (TU_BSWAP32(u32))

   #define tu_htole16(u16) (u16)
   #define tu_le16toh(u16) (u16)

   #define tu_htole32(u32) (u32)
   #define tu_le32toh(u32) (u32)

 #elif (TU_BYTE_ORDER == TU_BIG_ENDIAN)

   #define tu_htons(u16)  (u16)
   #define tu_ntohs(u16)  (u16)

   #define tu_htonl(u32)  (u32)
   #define tu_ntohl(u32)  (u32)

   #define tu_htole16(u16) (TU_BSWAP16(u16))
   #define tu_le16toh(u16) (TU_BSWAP16(u16))

   #define tu_htole32(u32) (TU_BSWAP32(u32))
   #define tu_le32toh(u32) (TU_BSWAP32(u32))

 #else
   #error Byte order is undefined
 #endif
	/*
	* The MIT License (MIT)
	*
	* Copyright (c) 2019 Ha Thach (tinyusb.org)
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*
	* This file is part of the TinyUSB stack.
	*/

	#pragma once

	#define TU_TOKEN(x) x
	#define TU_STRING(x) #x ///< stringify without expand
	#define TU_XSTRING(x) TU_STRING(x) ///< expand then stringify
	#define TU_STRCAT(a, b) a##b ///< concat without expand
	#define TU_STRCAT3(a, b, c) a##b##c ///< concat without expand
	#define TU_XSTRCAT(a, b) TU_STRCAT(a, b) ///< expand then concat
	#define TU_XSTRCAT3(a, b, c) TU_STRCAT3(a, b, c) ///< expand then concat 3 tokens

	#define TU_INCLUDE_PATH(_dir,_file) TU_XSTRING( TU_TOKEN(_dir)TU_TOKEN(_file) )

	#if defined __COUNTER__ && __COUNTER__ != __COUNTER__
	#define TU_COUNTER __COUNTER__
	#else
	#define TU_COUNTER __LINE__
	#endif

	// Compile-time Assert
	#if defined (__cplusplus) && __cplusplus >= 201103L
	#define TU_VERIFY_STATIC static_assert
	#elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
	#define TU_VERIFY_STATIC _Static_assert
	#elif defined(__CCRX__)
	#define TU_VERIFY_STATIC(const_expr, _mess) typedef char TU_XSTRCAT(_verify_static_, TU_COUNTER)[(const_expr) ? 1 : 0];
	#else
	#define TU_VERIFY_STATIC(const_expr, _mess) enum { TU_XSTRCAT(_verify_static_, TU_COUNTER) = 1/(!!(const_expr)) }
	#endif

	/* --------------------- Fuzzing types -------------------------------------- */
	#ifdef _FUZZ
	#define tu_static static __thread
	#else
	#define tu_static static
	#endif

	// for declaration of reserved field, make use of TU_COUNTER
	#define TU_RESERVED TU_XSTRCAT(reserved, TU_COUNTER)

	#define TU_LITTLE_ENDIAN (0x12u)
	#define TU_BIG_ENDIAN (0x21u)

	/------------------------------------------------------------------/
	/* Count number of arguments of __VA_ARGS__
	* - reference www.stackoverflow.com/questions/2124339/c-preprocessor-va-args-number-of-arguments
	* - TU_GET_NTH_ARG() takes args >= N (64) but only expand to Nth one (64th)
	* - TU_NARG_RSEQ_N() is reverse sequential to N to add padding to have
	* Nth position is the same as the number of arguments
	* - ##__VA_ARGS__ is used to deal with 0 paramerter (swallows comma)
	------------------------------------------------------------------/
	#if defined(__CCRX__)
	#define TU_ARGS_NUM(...) TU_NARG_IMPL(_0, __VA_ARGS__, TU_NARG_RSEQ_N())
	#else
	#define TU_ARGS_NUM(...) TU_NARG_IMPL(_0, ##__VA_ARGS__, TU_NARG_RSEQ_N())
	#endif

	#define TU_NARG_IMPL(...) TU_GET_NTH_ARG(__VA_ARGS__)
	#define TU_GET_NTH_ARG( \
	_1, _2, _3, _4, _5, _6, _7, _8, _9,_10, \
	_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
	_21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
	_31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
	_41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
	_51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
	_61,_62,_63,N,...) N
	#define TU_NARG_RSEQ_N() \
	62,61,60, \
	59,58,57,56,55,54,53,52,51,50, \
	49,48,47,46,45,44,43,42,41,40, \
	39,38,37,36,35,34,33,32,31,30, \
	29,28,27,26,25,24,23,22,21,20, \
	19,18,17,16,15,14,13,12,11,10, \
	9,8,7,6,5,4,3,2,1,0

	// Apply a macro X to each of the arguments with a separation/delimiter
	#define TU_ARGS_APPLY(_X, _s, ...) TU_XSTRCAT(TU_ARGS_APPLY_, TU_ARGS_NUM(__VA_ARGS__))(_X, _s, __VA_ARGS__)

	#define TU_ARGS_APPLY_1(_X, _s, _a1) _X(_a1)
	#define TU_ARGS_APPLY_2(_X, _s, _a1, _a2) _X(_a1) _s _X(_a2)
	#define TU_ARGS_APPLY_3(_X, _s, _a1, _a2, _a3) _X(_a1) _s TU_ARGS_APPLY_2(_X, _s, _a2, _a3)
	#define TU_ARGS_APPLY_4(_X, _s, _a1, _a2, _a3, _a4) _X(_a1) _s TU_ARGS_APPLY_3(_X, _s, _a2, _a3, _a4)
	#define TU_ARGS_APPLY_5(_X, _s, _a1, _a2, _a3, _a4, _a5) _X(_a1) _s TU_ARGS_APPLY_4(_X, _s, _a2, _a3, _a4, _a5)
	#define TU_ARGS_APPLY_6(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6) _X(_a1) _s TU_ARGS_APPLY_5(_X, _s, _a2, _a3, _a4, _a5, _a6)
	#define TU_ARGS_APPLY_7(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7) _X(_a1) _s TU_ARGS_APPLY_6(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7)
	#define TU_ARGS_APPLY_8(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7, _a8) _X(_a1) _s TU_ARGS_APPLY_7(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7, _a8)

	// Apply a macro X to each of the arguments and expand the result with comma
	#define TU_ARGS_APPLY_EXPAND(_X, ...) TU_XSTRCAT(TU_ARGS_APPLY_EXPAND_, TU_ARGS_NUM(__VA_ARGS__))(_X, __VA_ARGS__)

	#define TU_ARGS_APPLY_EXPAND_1(_X, _a1) _X(_a1)
	#define TU_ARGS_APPLY_EXPAND_2(_X, _a1, _a2) _X(_a1), _X(_a2)
	#define TU_ARGS_APPLY_EXPAND_3(_X, _a1, _a2, _a3) _X(_a1), TU_ARGS_APPLY_EXPAND_2(_X, _a2, _a3)
	#define TU_ARGS_APPLY_EXPAND_4(_X, _a1, _a2, _a3, _a4) _X(_a1), TU_ARGS_APPLY_EXPAND_3(_X, _a2, _a3, _a4)
	#define TU_ARGS_APPLY_EXPAND_5(_X, _a1, _a2, _a3, _a4, _a5) _X(_a1), TU_ARGS_APPLY_EXPAND_4(_X, _a2, _a3, _a4, _a5)
	#define TU_ARGS_APPLY_EXPAND_6(_X, _a1, _a2, _a3, _a4, _a5, _a6) _X(_a1), TU_ARGS_APPLY_EXPAND_5(_X, _a2, _a3, _a4, _a5, _a6)
	#define TU_ARGS_APPLY_EXPAND_7(_X, _a1, _a2, _a3, _a4, _a5, _a6, _a7) _X(_a1), TU_ARGS_APPLY_EXPAND_6(_X, _a2, _a3, _a4, _a5, _a6, _a7)
	#define TU_ARGS_APPLY_EXPAND_8(_X, _a1, _a2, _a3, _a4, _a5, _a6, _a7, _a8) _X(_a1), TU_ARGS_APPLY_EXPAND_7(_X, _a2, _a3, _a4, _a5, _a6, _a7, _a8)

	//--------------------------------------------------------------------+
	// Macro for function default arguments
	//--------------------------------------------------------------------+
	#define TU_GET_3RD_ARG(arg1, arg2, arg3, ...) arg3

	// function expand with number of arguments
	#define TU_FUNC_OPTIONAL_ARG(func, ...) TU_XSTRCAT(func##_arg, TU_ARGS_NUM(__VA_ARGS__))(__VA_ARGS__)

	//--------------------------------------------------------------------+
	// Compiler Attribute Abstraction
	//--------------------------------------------------------------------+
	#if defined(__GNUC__) \|\| defined(__ICCARM__) \|\| defined(__TI_COMPILER_VERSION__)
	#if defined(__ICCARM__)
	#include <intrinsics.h> // for builtin functions
	#endif

	#define TU_ATTR_ALIGNED(Bytes) __attribute__((aligned(Bytes)))
	#define TU_ATTR_SECTION(sec_name) __attribute__((section(#sec_name)))
	#define TU_ATTR_PACKED __attribute__((packed))
	#define TU_ATTR_WEAK __attribute__((weak))
	// #define TU_ATTR_WEAK_ALIAS(f) __attribute__ ((weak, alias(#f)))
	#ifndef TU_ATTR_ALWAYS_INLINE // allow to override for debug
	#define TU_ATTR_ALWAYS_INLINE __attribute__((always_inline))
	#endif
	#define TU_ATTR_DEPRECATED(mess) __attribute__ ((deprecated(mess))) // warn if function with this attribute is used
	#define TU_ATTR_UNUSED __attribute__ ((unused)) // Function/Variable is meant to be possibly unused
	#define TU_ATTR_USED __attribute__ ((used)) // Function/Variable is meant to be used

	#define TU_ATTR_PACKED_BEGIN
	#define TU_ATTR_PACKED_END
	#define TU_ATTR_BIT_FIELD_ORDER_BEGIN
	#define TU_ATTR_BIT_FIELD_ORDER_END

	#if (defined(__has_attribute) && __has_attribute(__fallthrough__)) \|\| defined(__TI_COMPILER_VERSION__)
	#define TU_ATTR_FALLTHROUGH __attribute__((fallthrough))
	#else
	#define TU_ATTR_FALLTHROUGH \
	do { \
	} while (0) /* fallthrough */
	#endif

	// Endian conversion use well-known host to network (big endian) naming
	// For TI ARM compiler, __BYTE_ORDER__ is not defined for MSP430 but still LE
	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ \|\| defined(__MSP430__)
	#define TU_BYTE_ORDER TU_LITTLE_ENDIAN
	#else
	#define TU_BYTE_ORDER TU_BIG_ENDIAN
	#endif

	// Unfortunately XC16 doesn't provide builtins for 32bit endian conversion
	#if defined(__XC16)
	#define TU_BSWAP16(u16) (__builtin_swap(u16))
	#define TU_BSWAP32(u32) ((((u32) & 0xff000000) >> 24) \| \
	(((u32) & 0x00ff0000) >> 8) \| \
	(((u32) & 0x0000ff00) << 8) \| \
	(((u32) & 0x000000ff) << 24))
	#else
	#define TU_BSWAP16(u16) (__builtin_bswap16(u16))
	#define TU_BSWAP32(u32) (__builtin_bswap32(u32))
	#endif

	// List of obsolete callback function that is renamed and should not be defined.
	// Put it here since only gcc support this pragma
	#if !defined(__ARMCC_VERSION) && !defined(__ICCARM__)
	#pragma GCC poison tud_vendor_control_request_cb
	#endif

	#elif defined(__ICCARM__)
	#include <intrinsics.h>
	#define TU_ATTR_ALIGNED(Bytes) __attribute__ ((aligned(Bytes)))
	#define TU_ATTR_SECTION(sec_name) __attribute__ ((section(#sec_name)))
	#define TU_ATTR_PACKED __attribute__ ((packed))
	#define TU_ATTR_WEAK __attribute__ ((weak))
	// #define TU_ATTR_WEAK_ALIAS(f) __attribute__ ((weak, alias(#f)))
	#ifndef TU_ATTR_ALWAYS_INLINE // allow to override for debug
	#define TU_ATTR_ALWAYS_INLINE __attribute__ ((always_inline))
	#endif
	#define TU_ATTR_DEPRECATED(mess) __attribute__ ((deprecated(mess))) // warn if function with this attribute is used
	#define TU_ATTR_UNUSED __attribute__ ((unused)) // Function/Variable is meant to be possibly unused
	#define TU_ATTR_USED __attribute__ ((used)) // Function/Variable is meant to be used
	#define TU_ATTR_FALLTHROUGH do {} while (0) /* fallthrough */

	#define TU_ATTR_PACKED_BEGIN
	#define TU_ATTR_PACKED_END
	#define TU_ATTR_BIT_FIELD_ORDER_BEGIN
	#define TU_ATTR_BIT_FIELD_ORDER_END

	// Endian conversion use well-known host to network (big endian) naming
	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
	#define TU_BYTE_ORDER TU_LITTLE_ENDIAN
	#else
	#define TU_BYTE_ORDER TU_BIG_ENDIAN
	#endif

	#define TU_BSWAP16(u16) (__iar_builtin_REV16(u16))
	#define TU_BSWAP32(u32) (__iar_builtin_REV(u32))

	#elif defined(__CCRX__)
	#define TU_ATTR_ALIGNED(Bytes)
	#define TU_ATTR_SECTION(sec_name)
	#define TU_ATTR_PACKED
	#define TU_ATTR_WEAK
	// #define TU_ATTR_WEAK_ALIAS(f)
	#define TU_ATTR_ALWAYS_INLINE
	#define TU_ATTR_DEPRECATED(mess)
	#define TU_ATTR_UNUSED
	#define TU_ATTR_USED
	#define TU_ATTR_FALLTHROUGH do {} while (0) /* fallthrough */

	#define TU_ATTR_PACKED_BEGIN _Pragma("pack")
	#define TU_ATTR_PACKED_END _Pragma("packoption")
	#define TU_ATTR_BIT_FIELD_ORDER_BEGIN _Pragma("bit_order right")
	#define TU_ATTR_BIT_FIELD_ORDER_END _Pragma("bit_order")

	// Endian conversion use well-known host to network (big endian) naming
	#if defined(__LIT)
	#define TU_BYTE_ORDER TU_LITTLE_ENDIAN
	#else
	#define TU_BYTE_ORDER TU_BIG_ENDIAN
	#endif

	#define TU_BSWAP16(u16) ((unsigned short)_builtin_revw((unsigned long)u16))
	#define TU_BSWAP32(u32) (_builtin_revl(u32))

	#else
	#error "Compiler attribute porting is required"
	#endif


	#if (TU_BYTE_ORDER == TU_LITTLE_ENDIAN)

	#define tu_htons(u16) (TU_BSWAP16(u16))
	#define tu_ntohs(u16) (TU_BSWAP16(u16))

	#define tu_htonl(u32) (TU_BSWAP32(u32))
	#define tu_ntohl(u32) (TU_BSWAP32(u32))

	#define tu_htole16(u16) (u16)
	#define tu_le16toh(u16) (u16)

	#define tu_htole32(u32) (u32)
	#define tu_le32toh(u32) (u32)

	#elif (TU_BYTE_ORDER == TU_BIG_ENDIAN)

	#define tu_htons(u16) (u16)
	#define tu_ntohs(u16) (u16)

	#define tu_htonl(u32) (u32)
	#define tu_ntohl(u32) (u32)

	#define tu_htole16(u16) (TU_BSWAP16(u16))
	#define tu_le16toh(u16) (TU_BSWAP16(u16))

	#define tu_htole32(u32) (TU_BSWAP32(u32))
	#define tu_le32toh(u32) (TU_BSWAP32(u32))

	#else
	#error Byte order is undefined
	#endif