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
  71                 #include "Architectures.h"
  72                 #include "Attributes.h"
  73                 #include "BoardTypes.h"
  74
  75         /* Architecture specific utility includes: */
  76                 #if (ARCH == ARCH_AVR8)
  77                         #include <avr/io.h>
  78                         #include <avr/interrupt.h>
  79                         #include <avr/pgmspace.h>
  80                         #include <avr/eeprom.h>
  81                         #include <avr/boot.h>
  82                         #include <util/atomic.h>
  83                         #include <util/delay.h>
  84                 #endif
  85
  86         /* Public Interface - May be used in end-application: */
  87                 /* Macros: */
  88                         /** Macro for encasing other multi-statement macros. This should be used along with an opening brace
  89                          *  before the start of any multi-statement macro, so that the macros contents as a whole are treated
  90                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  91                          *  a block (such as inline \c if statements).
  92                          */
  93                         #define MACROS                  do
  94
  95                         /** Macro for encasing other multi-statement macros. This should be used along with a preceding closing
  96                          *  brace at the end of any multi-statement macro, so that the macros contents as a whole are treated
  97                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  98                          *  a block (such as inline \c if statements).
  99                          */
 100                         #define MACROE                  while (0)
 101
 102                         /** Convenience macro to determine the larger of two values.
 103                          *
 104                          *  \note This macro should only be used with operands that do not have side effects from being evaluated
 105                          *        multiple times.
 106                          *
 107                          *  \param[in] x  First value to compare
 108                          *  \param[in] y  First value to compare
 109                          *
 110                          *  \return The larger of the two input parameters
 111                          */
 112                         #if !defined(MAX) || defined(__DOXYGEN__)
 113                                 #define MAX(x, y)               ((x > y) ? x : y)
 114                         #endif
 115
 116                         /** Convenience macro to determine the smaller of two values.
 117                          *
 118                          *  \note This macro should only be used with operands that do not have side effects from being evaluated
 119                          *        multiple times.
 120                          *
 121                          *  \param[in] x  First value to compare
 122                          *  \param[in] y  First value to compare
 123                          *
 124                          *  \return The smaller of the two input parameters
 125                          */
 126                         #if !defined(MIN) || defined(__DOXYGEN__)
 127                                 #define MIN(x, y)               ((x < y) ? x : y)
 128                         #endif
 129
 130                         #if (ARCH == ARCH_AVR8) || defined(__DOXYGEN__)
 131                                 /** Defines a volatile \c NOP statement which cannot be optimized out by the compiler, and thus can always
 132                                  *  be set as a breakpoint in the resulting code. Useful for debugging purposes, where the optimiser
 133                                  *  removes/reorders code to the point where break points cannot reliably be set.
 134                                  *
 135                                  *  \ingroup Group_Debugging
 136                                  */
 137                                 #define JTAG_DEBUG_POINT()      __asm__ __volatile__ ("NOP" ::)
 138
 139                                 /** Defines an explicit JTAG break point in the resulting binary via the assembly \c BREAK statement. When
 140                                  *  a JTAG is used, this causes the program execution to halt when reached until manually resumed.
 141                                  *
 142                                  *  \ingroup Group_Debugging
 143                                  */
 144                                 #define JTAG_DEBUG_BREAK()      __asm__ __volatile__ ("BREAK" ::)
 145
 146                                 #if !defined(pgm_read_ptr) || defined(__DOXYGEN__)
 147                                         /** Reads a pointer out of PROGMEM space. This is currently a wrapper for the avr-libc \c pgm_read_ptr()
 148                                          *  macro with a \c void* cast, so that its value can be assigned directly to a pointer variable or used
 149                                          *  in pointer arithmetic without further casting in C. In a future avr-libc distribution this will be
 150                                          *  part of the standard API and will be implemented in a more formal manner.
 151                                          *
 152                                          *  \param[in] Addr  Address of the pointer to read.
 153                                          *
 154                                          *  \return Pointer retrieved from PROGMEM space.
 155                                          */
 156                                         #define pgm_read_ptr(Addr)    (void*)pgm_read_word(Addr)
 157                                 #endif
 158
 159                                 /** Macro for testing condition "x" and breaking via \ref JTAG_DEBUG_BREAK() if the condition is false.
 160                                  *
 161                                  *  \param[in] Condition  Condition that will be evaluated,
 162                                  *
 163                                  *  \ingroup Group_Debugging
 164                                 */
 165                                 #define JTAG_DEBUG_ASSERT(Condition)    MACROS{ if (!(Condition)) { JTAG_DEBUG_BREAK(); } }MACROE
 166
 167                                 /** Macro for testing condition "x" and writing debug data to the stdout stream if \c false. The stdout stream
 168                                  *  must be pre-initialized before this macro is run and linked to an output device, such as the AVR's USART
 169                                  *  peripheral.
 170                                  *
 171                                  *  The output takes the form "{FILENAME}: Function {FUNCTION NAME}, Line {LINE NUMBER}: Assertion {Condition} failed."
 172                                  *
 173                                  *  \param[in] Condition  Condition that will be evaluated,
 174                                  *
 175                                  *  \ingroup Group_Debugging
 176                                  */
 177                                 #define STDOUT_ASSERT(Condition)        MACROS{ if (!(x)) { printf_P(PSTR("%s: Function \"%s\", Line %d: "   \
 178                                                                                 "Assertion \"%s\" failed.\r\n"),     \
 179                                                                                 __FILE__, __func__, __LINE__, #Condition); } }MACROE
 180                         #endif
 181
 182                         /** Forces GCC to use pointer indirection (via the AVR's pointer register pairs) when accessing the given
 183                          *  struct pointer. In some cases GCC will emit non-optimal assembly code when accessing a structure through
 184                          *  a pointer, resulting in a larger binary. When this macro is used on a (non \c const) structure pointer before
 185                          *  use, it will force GCC to use pointer indirection on the elements rather than direct store and load
 186                          *  instructions.
 187                          *
 188                          *  \param[in, out] StructPtr  Pointer to a structure which is to be forced into indirect access mode.
 189                          */
 190                         #define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr))
 191
 192                         /** Swaps the byte ordering of a 16-bit value at compile time. Do not use this macro for swapping byte orderings
 193                          *  of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used
 194                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 195                          *  inline function variant.
 196                          *
 197                          *  \param[in]  x  16-bit value whose byte ordering is to be swapped.
 198                          *
 199                          *  \return Input value with the byte ordering reversed.
 200                          */
 201                         #define SWAPENDIAN_16(x)          ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8))
 202
 203                         /** Swaps the byte ordering of a 32-bit value at compile time. Do not use this macro for swapping byte orderings
 204                          *  of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used
 205                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 206                          *  inline function variant.
 207                          *
 208                          *  \param[in]  x  32-bit value whose byte ordering is to be swapped.
 209                          *
 210                          *  \return Input value with the byte ordering reversed.
 211                          */
 212                         #define SWAPENDIAN_32(x)          ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \
 213                                                            (((x) & 0x0000FF00UL) << 8UL)  | (((x) & 0x000000FFUL) << 24UL))
 214
 215                 /* Inline Functions: */
 216                         /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1,
 217                          *  etc.
 218                          *
 219                          *  \ingroup Group_BitManip
 220                          *
 221                          *  \param[in] Byte  Byte of data whose bits are to be reversed.
 222                          */
 223                         static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 224                         static inline uint8_t BitReverse(uint8_t Byte)
 225                         {
 226                                 Byte = (((Byte & 0xF0) >> 4) | ((Byte & 0x0F) << 4));
 227                                 Byte = (((Byte & 0xCC) >> 2) | ((Byte & 0x33) << 2));
 228                                 Byte = (((Byte & 0xAA) >> 1) | ((Byte & 0x55) << 1));
 229
 230                                 return Byte;
 231                         }
 232
 233                         /** Function to reverse the byte ordering of the individual bytes in a 16 bit number.
 234                          *
 235                          *  \ingroup Group_BitManip
 236                          *
 237                          *  \param[in] Word  Word of data whose bytes are to be swapped.
 238                          */
 239                         static inline uint16_t SwapEndian_16(const uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 240                         static inline uint16_t SwapEndian_16(const uint16_t Word)
 241                         {
 242                                 uint8_t Temp;
 243
 244                                 union
 245                                 {
 246                                         uint16_t Word;
 247                                         uint8_t  Bytes[2];
 248                                 } Data;
 249
 250                                 Data.Word = Word;
 251
 252                                 Temp = Data.Bytes[0];
 253                                 Data.Bytes[0] = Data.Bytes[1];
 254                                 Data.Bytes[1] = Temp;
 255
 256                                 return Data.Word;
 257                         }
 258
 259                         /** Function to reverse the byte ordering of the individual bytes in a 32 bit number.
 260                          *
 261                          *  \ingroup Group_BitManip
 262                          *
 263                          *  \param[in] DWord  Double word of data whose bytes are to be swapped.
 264                          */
 265                         static inline uint32_t SwapEndian_32(const uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 266                         static inline uint32_t SwapEndian_32(const uint32_t DWord)
 267                         {
 268                                 uint8_t Temp;
 269
 270                                 union
 271                                 {
 272                                         uint32_t DWord;
 273                                         uint8_t  Bytes[4];
 274                                 } Data;
 275
 276                                 Data.DWord = DWord;
 277
 278                                 Temp = Data.Bytes[0];
 279                                 Data.Bytes[0] = Data.Bytes[3];
 280                                 Data.Bytes[3] = Temp;
 281
 282                                 Temp = Data.Bytes[1];
 283                                 Data.Bytes[1] = Data.Bytes[2];
 284                                 Data.Bytes[2] = Temp;
 285
 286                                 return Data.DWord;
 287                         }
 288
 289                         /** Function to reverse the byte ordering of the individual bytes in a n byte number.
 290                          *
 291                          *  \ingroup Group_BitManip
 292                          *
 293                          *  \param[in,out] Data   Pointer to a number containing an even number of bytes to be reversed.
 294                          *  \param[in]     Bytes  Length of the data in bytes.
 295                          */
 296                         static inline void SwapEndian_n(void* Data,
 297                                                         uint8_t Bytes) ATTR_NON_NULL_PTR_ARG(1);
 298                         static inline void SwapEndian_n(void* Data,
 299                                                         uint8_t Bytes)
 300                         {
 301                                 uint8_t* CurrDataPos = (uint8_t*)Data;
 302
 303                                 while (Bytes > 1)
 304                                 {
 305                                         uint8_t Temp = *CurrDataPos;
 306                                         *CurrDataPos = *(CurrDataPos + Bytes - 1);
 307                                         *(CurrDataPos + Bytes - 1) = Temp;
 308
 309                                         CurrDataPos++;
 310                                         Bytes -= 2;
 311                                 }
 312                         }
 313
 314 #endif
 315
 316 /** @} */
 317