Endianness.h 17.3 KB
 Dean Camera committed Mar 13, 2011 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 /* 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  Dean Camera committed Apr 04, 2011 63 64 65 66  #if !(defined(ARCH_BIG_ENDIAN) || defined(ARCH_LITTLE_ENDIAN)) #error ARCH_BIG_ENDIAN or ARCH_LITTLE_ENDIAN not set for the specified architecture. #endif  Dean Camera committed Mar 13, 2011 67 68 69 70 71 72 73 74 75 76  /* 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 *  77  * \param[in] x 16-bit value whose byte ordering is to be swapped.  Dean Camera committed Mar 13, 2011 78 79 80 81 82 83 84 85 86 87 88 89  * * \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 *  90  * \param[in] x 32-bit value whose byte ordering is to be swapped.  Dean Camera committed Mar 13, 2011 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442  * * \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 *  443 444  * \param[in,out] Data Pointer to a number containing an even number of bytes to be reversed. * \param[in] Length Length of the data in bytes.  Dean Camera committed Mar 13, 2011 445  */  446 447 448 449  static inline void SwapEndian_n(void* const Data, uint8_t Length) ATTR_NON_NULL_PTR_ARG(1); static inline void SwapEndian_n(void* const Data, uint8_t Length)  Dean Camera committed Mar 13, 2011 450 451 452  { uint8_t* CurrDataPos = (uint8_t*)Data;  453  while (Length > 1)  Dean Camera committed Mar 13, 2011 454 455  { uint8_t Temp = *CurrDataPos;  456 457  *CurrDataPos = *(CurrDataPos + Length - 1); *(CurrDataPos + Length - 1) = Temp;  Dean Camera committed Mar 13, 2011 458 459  CurrDataPos++;  460  Length -= 2;  Dean Camera committed Mar 13, 2011 461 462 463 464 465 466  } } #endif /** @} */