LUFA/Common/Common.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *  \brief Common library convenience headers, macros and functions.
  33  *
  34  *  \copydetails Group_Common
  35  */
  36
  37 /** \defgroup Group_Common Common Utility Headers - LUFA/Drivers/Common/Common.h
  38  *  \brief Common library convenience headers, macros and functions.
  39  *
  40  *  Common utility headers containing macros, functions, enums and types which are common to all
  41  *  aspects of the library.
  42  *
  43  *  @{
  44  */
  45
  46 /** \defgroup Group_Debugging Debugging Macros
  47  *  \brief Convenience macros to aid in debugging applications.
  48  *
  49  *  Macros to aid debugging of a user application.
  50  */
  51
  52 /** \defgroup Group_BitManip Endian and Bit Macros
  53  *  \brief Convenience macros to aid in bit manipulations and endianness transforms.
  54  *
  55  *  Functions for swapping endianness and reversing bit orders of data.
  56  */
  57
  58 #ifndef __LUFA_COMMON_H__
  59 #define __LUFA_COMMON_H__
  60
  61         /* Macros: */
  62                 #if !defined(__DOXYGEN__)
  63                         #define __INCLUDE_FROM_COMMON_H
  64                 #endif
  65
  66         /* Includes: */
  67                 #include <stdint.h>
  68                 #include <stdbool.h>
  69                 #include <string.h>
  70                 #include <stddef.h>
  71
  72                 #include "Architectures.h"
  73                 #include "Attributes.h"
  74                 #include "BoardTypes.h"
  75
  76         /* Architecture specific utility includes: */
  77                 #if defined(__DOXYGEN__)
  78                         /** Type define for an unsigned integer the same width as the selected architecture's machine register. */
  79                         typedef MACHINE_REG_t uint_reg_t;
  80                 #elif (ARCH == ARCH_AVR8)
  81                         #include <avr/io.h>
  82                         #include <avr/interrupt.h>
  83                         #include <avr/pgmspace.h>
  84                         #include <avr/eeprom.h>
  85                         #include <avr/boot.h>
  86                         #include <util/atomic.h>
  87                         #include <util/delay.h>
  88
  89                         typedef uint8_t uint_reg_t;
  90                 #elif (ARCH == ARCH_UC3B)
  91                         #include <avr32/io.h>
  92
  93                         typedef uint32_t uint_reg_t;
  94
  95                         #warning The UC3B architecture support is currently experimental and incomplete!
  96                 #endif
  97
  98         /* Public Interface - May be used in end-application: */
  99                 /* Macros: */
 100                         /** Macro for encasing other multi-statement macros. This should be used along with an opening brace
 101                          *  before the start of any multi-statement macro, so that the macros contents as a whole are treated
 102                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
 103                          *  a block (such as inline \c if statements).
 104                          */
 105                         #define MACROS                  do
 106
 107                         /** Macro for encasing other multi-statement macros. This should be used along with a preceding closing
 108                          *  brace at the end of any multi-statement macro, so that the macros contents as a whole are treated
 109                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
 110                          *  a block (such as inline \c if statements).
 111                          */
 112                         #define MACROE                  while (0)
 113
 114                         /** Convenience macro to determine the larger of two values.
 115                          *
 116                          *  \note This macro should only be used with operands that do not have side effects from being evaluated
 117                          *        multiple times.
 118                          *
 119                          *  \param[in] x  First value to compare
 120                          *  \param[in] y  First value to compare
 121                          *
 122                          *  \return The larger of the two input parameters
 123                          */
 124                         #if !defined(MAX) || defined(__DOXYGEN__)
 125                                 #define MAX(x, y)               ((x > y) ? x : y)
 126                         #endif
 127
 128                         /** Convenience macro to determine the smaller of two values.
 129                          *
 130                          *  \note This macro should only be used with operands that do not have side effects from being evaluated
 131                          *        multiple times.
 132                          *
 133                          *  \param[in] x  First value to compare
 134                          *  \param[in] y  First value to compare
 135                          *
 136                          *  \return The smaller of the two input parameters
 137                          */
 138                         #if !defined(MIN) || defined(__DOXYGEN__)
 139                                 #define MIN(x, y)               ((x < y) ? x : y)
 140                         #endif
 141
 142                         #if (ARCH == ARCH_AVR8) || defined(__DOXYGEN__)
 143                                 /** Defines a volatile \c NOP statement which cannot be optimized out by the compiler, and thus can always
 144                                  *  be set as a breakpoint in the resulting code. Useful for debugging purposes, where the optimiser
 145                                  *  removes/reorders code to the point where break points cannot reliably be set.
 146                                  *
 147                                  *  \ingroup Group_Debugging
 148                                  */
 149                                 #define JTAG_DEBUG_POINT()      __asm__ __volatile__ ("NOP" ::)
 150
 151                                 /** Defines an explicit JTAG break point in the resulting binary via the assembly \c BREAK statement. When
 152                                  *  a JTAG is used, this causes the program execution to halt when reached until manually resumed.
 153                                  *
 154                                  *  \ingroup Group_Debugging
 155                                  */
 156                                 #define JTAG_DEBUG_BREAK()      __asm__ __volatile__ ("BREAK" ::)
 157
 158                                 #if !defined(pgm_read_ptr) || defined(__DOXYGEN__)
 159                                         /** Reads a pointer out of PROGMEM space on the AVR8 architecture. This is currently a wrapper for the
 160                                          *  avr-libc \c pgm_read_ptr() macro with a \c void* cast, so that its value can be assigned directly
 161                                          *  to a pointer variable or used in pointer arithmetic without further casting in C. In a future
 162                                          *  avr-libc distribution this will be part of the standard API and will be implemented in a more formal
 163                                          *  manner.
 164                                          *
 165                                          *  \param[in] Addr  Address of the pointer to read.
 166                                          *
 167                                          *  \return Pointer retrieved from PROGMEM space.
 168                                          */
 169                                         #define pgm_read_ptr(Addr)    (void*)pgm_read_word(Addr)
 170                                 #endif
 171
 172                                 /** Macro for testing condition "x" and breaking via \ref JTAG_DEBUG_BREAK() if the condition is false.
 173                                  *
 174                                  *  \param[in] Condition  Condition that will be evaluated,
 175                                  *
 176                                  *  \ingroup Group_Debugging
 177                                 */
 178                                 #define JTAG_DEBUG_ASSERT(Condition)    MACROS{ if (!(Condition)) { JTAG_DEBUG_BREAK(); } }MACROE
 179
 180                                 /** Macro for testing condition "x" and writing debug data to the stdout stream if \c false. The stdout stream
 181                                  *  must be pre-initialized before this macro is run and linked to an output device, such as the microcontroller's
 182                                  *  USART peripheral.
 183                                  *
 184                                  *  The output takes the form "{FILENAME}: Function {FUNCTION NAME}, Line {LINE NUMBER}: Assertion {Condition} failed."
 185                                  *
 186                                  *  \param[in] Condition  Condition that will be evaluated,
 187                                  *
 188                                  *  \ingroup Group_Debugging
 189                                  */
 190                                 #define STDOUT_ASSERT(Condition)        MACROS{ if (!(x)) { printf_P(PSTR("%s: Function \"%s\", Line %d: "   \
 191                                                                                 "Assertion \"%s\" failed.\r\n"),     \
 192                                                                                 __FILE__, __func__, __LINE__, #Condition); } }MACROE
 193                         #endif
 194
 195                         /** Forces GCC to use pointer indirection (via the device's pointer register pairs) when accessing the given
 196                          *  struct pointer. In some cases GCC will emit non-optimal assembly code when accessing a structure through
 197                          *  a pointer, resulting in a larger binary. When this macro is used on a (non \c const) structure pointer before
 198                          *  use, it will force GCC to use pointer indirection on the elements rather than direct store and load
 199                          *  instructions.
 200                          *
 201                          *  \param[in, out] StructPtr  Pointer to a structure which is to be forced into indirect access mode.
 202                          */
 203                         #define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr))
 204
 205                         /** Swaps the byte ordering of a 16-bit value at compile time. Do not use this macro for swapping byte orderings
 206                          *  of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used
 207                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 208                          *  inline function variant.
 209                          *
 210                          *  \param[in]  x  16-bit value whose byte ordering is to be swapped.
 211                          *
 212                          *  \return Input value with the byte ordering reversed.
 213                          */
 214                         #define SWAPENDIAN_16(x)          ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8))
 215
 216                         /** Swaps the byte ordering of a 32-bit value at compile time. Do not use this macro for swapping byte orderings
 217                          *  of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used
 218                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 219                          *  inline function variant.
 220                          *
 221                          *  \param[in]  x  32-bit value whose byte ordering is to be swapped.
 222                          *
 223                          *  \return Input value with the byte ordering reversed.
 224                          */
 225                         #define SWAPENDIAN_32(x)          ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \
 226                                                            (((x) & 0x0000FF00UL) << 8UL)  | (((x) & 0x000000FFUL) << 24UL))
 227
 228                 /* Inline Functions: */
 229                         /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1,
 230                          *  etc.
 231                          *
 232                          *  \ingroup Group_BitManip
 233                          *
 234                          *  \param[in] Byte  Byte of data whose bits are to be reversed.
 235                          */
 236                         static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 237                         static inline uint8_t BitReverse(uint8_t Byte)
 238                         {
 239                                 Byte = (((Byte & 0xF0) >> 4) | ((Byte & 0x0F) << 4));
 240                                 Byte = (((Byte & 0xCC) >> 2) | ((Byte & 0x33) << 2));
 241                                 Byte = (((Byte & 0xAA) >> 1) | ((Byte & 0x55) << 1));
 242
 243                                 return Byte;
 244                         }
 245
 246                         /** Function to reverse the byte ordering of the individual bytes in a 16 bit number.
 247                          *
 248                          *  \ingroup Group_BitManip
 249                          *
 250                          *  \param[in] Word  Word of data whose bytes are to be swapped.
 251                          */
 252                         static inline uint16_t SwapEndian_16(const uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 253                         static inline uint16_t SwapEndian_16(const uint16_t Word)
 254                         {
 255                                 uint8_t Temp;
 256
 257                                 union
 258                                 {
 259                                         uint16_t Word;
 260                                         uint8_t  Bytes[2];
 261                                 } Data;
 262
 263                                 Data.Word = Word;
 264
 265                                 Temp = Data.Bytes[0];
 266                                 Data.Bytes[0] = Data.Bytes[1];
 267                                 Data.Bytes[1] = Temp;
 268
 269                                 return Data.Word;
 270                         }
 271
 272                         /** Function to reverse the byte ordering of the individual bytes in a 32 bit number.
 273                          *
 274                          *  \ingroup Group_BitManip
 275                          *
 276                          *  \param[in] DWord  Double word of data whose bytes are to be swapped.
 277                          */
 278                         static inline uint32_t SwapEndian_32(const uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 279                         static inline uint32_t SwapEndian_32(const uint32_t DWord)
 280                         {
 281                                 uint8_t Temp;
 282
 283                                 union
 284                                 {
 285                                         uint32_t DWord;
 286                                         uint8_t  Bytes[4];
 287                                 } Data;
 288
 289                                 Data.DWord = DWord;
 290
 291                                 Temp = Data.Bytes[0];
 292                                 Data.Bytes[0] = Data.Bytes[3];
 293                                 Data.Bytes[3] = Temp;
 294
 295                                 Temp = Data.Bytes[1];
 296                                 Data.Bytes[1] = Data.Bytes[2];
 297                                 Data.Bytes[2] = Temp;
 298
 299                                 return Data.DWord;
 300                         }
 301
 302                         /** Function to reverse the byte ordering of the individual bytes in a n byte number.
 303                          *
 304                          *  \ingroup Group_BitManip
 305                          *
 306                          *  \param[in,out] Data   Pointer to a number containing an even number of bytes to be reversed.
 307                          *  \param[in]     Bytes  Length of the data in bytes.
 308                          */
 309                         static inline void SwapEndian_n(void* Data,
 310                                                         uint8_t Bytes) ATTR_NON_NULL_PTR_ARG(1);
 311                         static inline void SwapEndian_n(void* Data,
 312                                                         uint8_t Bytes)
 313                         {
 314                                 uint8_t* CurrDataPos = (uint8_t*)Data;
 315
 316                                 while (Bytes > 1)
 317                                 {
 318                                         uint8_t Temp = *CurrDataPos;
 319                                         *CurrDataPos = *(CurrDataPos + Bytes - 1);
 320                                         *(CurrDataPos + Bytes - 1) = Temp;
 321
 322                                         CurrDataPos++;
 323                                         Bytes -= 2;
 324                                 }
 325                         }
 326
 327 #endif
 328
 329 /** @} */
 330