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 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 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  *
  48  *  Macros for debugging use.
  49  */
  50
  51 /** \defgroup Group_BitManip Endian and Bit Macros
  52  *
  53  *  Functions for swapping endianness and reversing bit orders.
  54  */
  55
  56 #ifndef __LUFA_COMMON_H__
  57 #define __LUFA_COMMON_H__
  58
  59         /* Macros: */
  60                 #if !defined(__DOXYGEN__)
  61                         #define __INCLUDE_FROM_COMMON_H
  62                 #endif
  63
  64         /* Includes: */
  65                 #include <stdint.h>
  66                 #include <stdbool.h>
  67                 #include <string.h>
  68
  69                 #include "Architectures.h"
  70                 #include "Attributes.h"
  71                 #include "BoardTypes.h"
  72
  73         /* Architecture specific utility includes: */
  74                 #if (ARCH == ARCH_AVR8)
  75                         #include <avr/io.h>
  76                         #include <avr/interrupt.h>
  77                         #include <avr/pgmspace.h>
  78                         #include <avr/eeprom.h>
  79                         #include <avr/boot.h>
  80                         #include <util/atomic.h>
  81                         #include <util/delay.h>
  82                 #endif
  83
  84         /* Public Interface - May be used in end-application: */
  85                 /* Macros: */
  86                         /** Macro for encasing other multi-statement macros. This should be used along with an opening brace
  87                          *  before the start of any multi-statement macro, so that the macros contents as a whole are treated
  88                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  89                          *  a block (such as inline \c if statements).
  90                          */
  91                         #define MACROS                  do
  92
  93                         /** Macro for encasing other multi-statement macros. This should be used along with a preceding closing
  94                          *  brace at the end of any multi-statement macro, so that the macros contents as a whole are treated
  95                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  96                          *  a block (such as inline \c if statements).
  97                          */
  98                         #define MACROE                  while (0)
  99
 100                         /** Convenience macro to determine the larger of two values.
 101                          *
 102                          *  \note This macro should only be used with operands that do not have side effects from being evaluated
 103                          *        multiple times.
 104                          *
 105                          *  \param[in] x  First value to compare
 106                          *  \param[in] y  First value to compare
 107                          *
 108                          *  \return The larger of the two input parameters
 109                          */
 110                         #if !defined(MAX) || defined(__DOXYGEN__)
 111                                 #define MAX(x, y)               ((x > y) ? x : y)
 112                         #endif
 113
 114                         /** Convenience macro to determine the smaller 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 smaller of the two input parameters
 123                          */
 124                         #if !defined(MIN) || defined(__DOXYGEN__)
 125                                 #define MIN(x, y)               ((x < y) ? x : y)
 126                         #endif
 127
 128                         #if (ARCH == ARCH_AVR8) || defined(__DOXYGEN__)
 129                                 /** Defines a volatile \c NOP statement which cannot be optimized out by the compiler, and thus can always
 130                                  *  be set as a breakpoint in the resulting code. Useful for debugging purposes, where the optimiser
 131                                  *  removes/reorders code to the point where break points cannot reliably be set.
 132                                  *
 133                                  *  \ingroup Group_Debugging
 134                                  */
 135                                 #define JTAG_DEBUG_POINT()      __asm__ __volatile__ ("NOP" ::)
 136
 137                                 /** Defines an explicit JTAG break point in the resulting binary via the assembly \c BREAK statement. When
 138                                  *  a JTAG is used, this causes the program execution to halt when reached until manually resumed.
 139                                  *
 140                                  *  \ingroup Group_Debugging
 141                                  */
 142                                 #define JTAG_DEBUG_BREAK()      __asm__ __volatile__ ("BREAK" ::)
 143
 144                                 #if !defined(pgm_read_ptr) || defined(__DOXYGEN__)
 145                                         /** Reads a pointer out of PROGMEM space. This is currently a wrapper for the avr-libc \c pgm_read_ptr()
 146                                          *  macro with a \c void* cast, so that its value can be assigned directly to a pointer variable or used
 147                                          *  in pointer arithmetic without further casting in C. In a future avr-libc distribution this will be
 148                                          *  part of the standard API and will be implemented in a more formal manner.
 149                                          *
 150                                          *  \param[in] Addr  Address of the pointer to read.
 151                                          *
 152                                          *  \return Pointer retrieved from PROGMEM space.
 153                                          */
 154                                         #define pgm_read_ptr(Addr)    (void*)pgm_read_word(Addr)
 155                                 #endif
 156
 157                                 /** Macro for testing condition "x" and breaking via \ref JTAG_DEBUG_BREAK() if the condition is false.
 158                                  *
 159                                  *  \param[in] Condition  Condition that will be evaluated,
 160                                  *
 161                                  *  \ingroup Group_Debugging
 162                                 */
 163                                 #define JTAG_DEBUG_ASSERT(Condition)    MACROS{ if (!(Condition)) { JTAG_DEBUG_BREAK(); } }MACROE
 164
 165                                 /** Macro for testing condition "x" and writing debug data to the stdout stream if \c false. The stdout stream
 166                                  *  must be pre-initialized before this macro is run and linked to an output device, such as the AVR's USART
 167                                  *  peripheral.
 168                                  *
 169                                  *  The output takes the form "{FILENAME}: Function {FUNCTION NAME}, Line {LINE NUMBER}: Assertion {Condition} failed."
 170                                  *
 171                                  *  \param[in] Condition  Condition that will be evaluated,
 172                                  *
 173                                  *  \ingroup Group_Debugging
 174                                  */
 175                                 #define STDOUT_ASSERT(Condition)        MACROS{ if (!(x)) { printf_P(PSTR("%s: Function \"%s\", Line %d: "   \
 176                                                                                 "Assertion \"%s\" failed.\r\n"),     \
 177                                                                                 __FILE__, __func__, __LINE__, #Condition); } }MACROE
 178                         #endif
 179
 180                         /** Forces GCC to use pointer indirection (via the AVR's pointer register pairs) when accessing the given
 181                          *  struct pointer. In some cases GCC will emit non-optimal assembly code when accessing a structure through
 182                          *  a pointer, resulting in a larger binary. When this macro is used on a (non \c const) structure pointer before
 183                          *  use, it will force GCC to use pointer indirection on the elements rather than direct store and load
 184                          *  instructions.
 185                          *
 186                          *  \param[in, out] StructPtr  Pointer to a structure which is to be forced into indirect access mode.
 187                          */
 188                         #define GCC_FORCE_POINTER_ACCESS(StructPtr) __asm__ __volatile__("" : "=b" (StructPtr) : "0" (StructPtr))
 189
 190                         /** Swaps the byte ordering of a 16-bit value at compile time. Do not use this macro for swapping byte orderings
 191                          *  of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used
 192                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 193                          *  inline function variant.
 194                          *
 195                          *  \param[in]  x  16-bit value whose byte ordering is to be swapped.
 196                          *
 197                          *  \return Input value with the byte ordering reversed.
 198                          */
 199                         #define SWAPENDIAN_16(x)          ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8))
 200
 201                         /** Swaps the byte ordering of a 32-bit value at compile time. Do not use this macro for swapping byte orderings
 202                          *  of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used
 203                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 204                          *  inline function variant.
 205                          *
 206                          *  \param[in]  x  32-bit value whose byte ordering is to be swapped.
 207                          *
 208                          *  \return Input value with the byte ordering reversed.
 209                          */
 210                         #define SWAPENDIAN_32(x)          ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \
 211                                                            (((x) & 0x0000FF00UL) << 8UL)  | (((x) & 0x000000FFUL) << 24UL))
 212
 213                 /* Inline Functions: */
 214                         /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1,
 215                          *  etc.
 216                          *
 217                          *  \ingroup Group_BitManip
 218                          *
 219                          *  \param[in] Byte  Byte of data whose bits are to be reversed.
 220                          */
 221                         static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 222                         static inline uint8_t BitReverse(uint8_t Byte)
 223                         {
 224                                 Byte = (((Byte & 0xF0) >> 4) | ((Byte & 0x0F) << 4));
 225                                 Byte = (((Byte & 0xCC) >> 2) | ((Byte & 0x33) << 2));
 226                                 Byte = (((Byte & 0xAA) >> 1) | ((Byte & 0x55) << 1));
 227
 228                                 return Byte;
 229                         }
 230
 231                         /** Function to reverse the byte ordering of the individual bytes in a 16 bit number.
 232                          *
 233                          *  \ingroup Group_BitManip
 234                          *
 235                          *  \param[in] Word  Word of data whose bytes are to be swapped.
 236                          */
 237                         static inline uint16_t SwapEndian_16(const uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 238                         static inline uint16_t SwapEndian_16(const uint16_t Word)
 239                         {
 240                                 uint8_t Temp;
 241
 242                                 union
 243                                 {
 244                                         uint16_t Word;
 245                                         uint8_t  Bytes[2];
 246                                 } Data;
 247
 248                                 Data.Word = Word;
 249
 250                                 Temp = Data.Bytes[0];
 251                                 Data.Bytes[0] = Data.Bytes[1];
 252                                 Data.Bytes[1] = Temp;
 253
 254                                 return Data.Word;
 255                         }
 256
 257                         /** Function to reverse the byte ordering of the individual bytes in a 32 bit number.
 258                          *
 259                          *  \ingroup Group_BitManip
 260                          *
 261                          *  \param[in] DWord  Double word of data whose bytes are to be swapped.
 262                          */
 263                         static inline uint32_t SwapEndian_32(const uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 264                         static inline uint32_t SwapEndian_32(const uint32_t DWord)
 265                         {
 266                                 uint8_t Temp;
 267
 268                                 union
 269                                 {
 270                                         uint32_t DWord;
 271                                         uint8_t  Bytes[4];
 272                                 } Data;
 273
 274                                 Data.DWord = DWord;
 275
 276                                 Temp = Data.Bytes[0];
 277                                 Data.Bytes[0] = Data.Bytes[3];
 278                                 Data.Bytes[3] = Temp;
 279
 280                                 Temp = Data.Bytes[1];
 281                                 Data.Bytes[1] = Data.Bytes[2];
 282                                 Data.Bytes[2] = Temp;
 283
 284                                 return Data.DWord;
 285                         }
 286
 287                         /** Function to reverse the byte ordering of the individual bytes in a n byte number.
 288                          *
 289                          *  \ingroup Group_BitManip
 290                          *
 291                          *  \param[in,out] Data   Pointer to a number containing an even number of bytes to be reversed.
 292                          *  \param[in]     Bytes  Length of the data in bytes.
 293                          */
 294                         static inline void SwapEndian_n(void* Data,
 295                                                         uint8_t Bytes) ATTR_NON_NULL_PTR_ARG(1);
 296                         static inline void SwapEndian_n(void* Data,
 297                                                         uint8_t Bytes)
 298                         {
 299                                 uint8_t* CurrDataPos = (uint8_t*)Data;
 300
 301                                 while (Bytes > 1)
 302                                 {
 303                                         uint8_t Temp = *CurrDataPos;
 304                                         *CurrDataPos = *(CurrDataPos + Bytes - 1);
 305                                         *(CurrDataPos + Bytes - 1) = Temp;
 306
 307                                         CurrDataPos++;
 308                                         Bytes -= 2;
 309                                 }
 310                         }
 311
 312 #endif
 313
 314 /** @} */
 315