LUFA/Common/Common.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  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  *  This file contains macros which are common to all library elements, and which may be useful in user code. It
  35  *  also includes other common headers, such as Atomic.h, Attributes.h and BoardTypes.h.
  36  */
  37
  38 /** @defgroup Group_Common Common Utility Headers - LUFA/Drivers/Common/Common.h
  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 __COMMON_H__
  57 #define __COMMON_H__
  58
  59         /* Includes: */
  60                 #include <avr/io.h>
  61
  62                 #include "Attributes.h"
  63                 #include "BoardTypes.h"
  64
  65         /* Public Interface - May be used in end-application: */
  66                 /* Macros: */
  67                         /** Macro for encasing other multi-statement macros. This should be used along with an opening brace
  68                          *  before the start of any multi-statement macro, so that the macros contents as a whole are treated
  69                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  70                          *  a block (such as inline IF statements).
  71                          */
  72                         #define MACROS                  do
  73
  74                         /** Macro for encasing other multi-statement macros. This should be used along with a preceding closing
  75                          *  brace at the end of any multi-statement macro, so that the macros contents as a whole are treated
  76                          *  as a discrete block and not as a list of separate statements which may cause problems when used as
  77                          *  a block (such as inline IF statements).
  78                          */
  79                         #define MACROE                  while (0)
  80
  81                         /** Defines a volatile NOP statement which cannot be optimized out by the compiler, and thus can always
  82                          *  be set as a breakpoint in the resulting code. Useful for debugging purposes, where the optimizer
  83                          *  removes/reorders code to the point where break points cannot reliably be set.
  84                          *
  85                          *  \ingroup Group_Debugging
  86                          */
  87                         #define JTAG_DEBUG_POINT()      asm volatile ("NOP" ::)
  88
  89                         /** Defines an explicit JTAG break point in the resulting binary via the ASM BREAK statement. When
  90                          *  a JTAG is used, this causes the program execution to halt when reached until manually resumed.
  91                          *
  92                          *  \ingroup Group_Debugging
  93                          */
  94                         #define JTAG_DEBUG_BREAK()      asm volatile ("BREAK" ::)
  95
  96                         /** Macro for testing condition "x" and breaking via JTAG_DEBUG_BREAK() if the condition is false.
  97                          *
  98                          *  \ingroup Group_Debugging
  99                         */
 100                         #define JTAG_DEBUG_ASSERT(x)    MACROS{ if (!(x)) { JTAG_DEBUG_BREAK(); } }MACROE
 101
 102                         /** Macro for testing condition "x" and writing debug data to the stdout stream if false. The stdout stream
 103                          *  must be pre-initialized before this macro is run and linked to an output device, such as the AVR's USART
 104                          *  peripheral.
 105                          *
 106                          *  The output takes the form "{FILENAME}: Function {FUNCTION NAME}, Line {LINE NUMBER}: Assertion {x} failed."
 107                          *
 108                          *  \ingroup Group_Debugging
 109                          */
 110                         #define STDOUT_ASSERT(x)        MACROS{ if (!(x)) { printf_P(PSTR("%s: Function \"%s\", Line %d: "   \
 111                                                                      "Assertion \"%s\" failed.\r\n"),     \
 112                                                                      __FILE__, __func__, __LINE__, #x); } }MACROE
 113
 114                         #if !defined(pgm_read_ptr) || defined(__DOXYGEN__)
 115                                 /** Reads a pointer out of PROGMEM space. This is currently a wrapper for the avr-libc pgm_read_ptr()
 116                                  *  macro with a void* cast, so that its value can be assigned diretly to a pointer variable or used
 117                                  *  in pointer arithmetic without further casting in C. In a future avr-libc distribution this will be
 118                                  *  part of the standard API and will be implemented in a more formal manner.
 119                                  *
 120                                  *  \param[in] Addr  Address of the pointer to read.
 121                                  *
 122                                  *  \return Pointer retrieved from PROGMEM space.
 123                                  */
 124                                 #define pgm_read_ptr(Addr)    (void*)pgm_read_word(Addr)
 125                         #endif
 126
 127                         /** Swaps the byte ordering of a 16-bit value at compile time. Do not use this macro for swapping byte orderings
 128                          *  of dynamic values computed at runtime, use \ref SwapEndian_16() instead. The result of this macro can be used
 129                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 130                          *  inline function variant.
 131                          *
 132                          *  \param[in]  x  16-bit value whose byte ordering is to be swapped.
 133                          *
 134                          *  \return Input value with the byte ordering reversed.
 135                          */
 136                         #define SWAPENDIAN_16(x)          ((((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8))
 137
 138                         /** Swaps the byte ordering of a 32-bit value at compile time. Do not use this macro for swapping byte orderings
 139                          *  of dynamic values computed at runtime- use \ref SwapEndian_32() instead. The result of this macro can be used
 140                          *  inside struct or other variable initializers outside of a function, something that is not possible with the
 141                          *  inline function variant.
 142                          *
 143                          *  \param[in]  x  32-bit value whose byte ordering is to be swapped.
 144                          *
 145                          *  \return Input value with the byte ordering reversed.
 146                          */
 147                         #define SWAPENDIAN_32(x)          ((((x) & 0xFF000000UL) >> 24UL) | (((x) & 0x00FF0000UL) >> 8UL) | \
 148                                                            (((x) & 0x0000FF00UL) << 8UL)  | (((x) & 0x000000FFUL) << 24UL))
 149
 150                 /* Inline Functions: */
 151                         /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1,
 152                          *  etc.
 153                          *
 154                          *  \ingroup Group_BitManip
 155                          *
 156                          *  \param[in] Byte  Byte of data whose bits are to be reversed.
 157                          */
 158                         static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 159                         static inline uint8_t BitReverse(uint8_t Byte)
 160                         {
 161                                 Byte = (((Byte & 0xF0) >> 4) | ((Byte & 0x0F) << 4));
 162                                 Byte = (((Byte & 0xCC) >> 2) | ((Byte & 0x33) << 2));
 163                                 Byte = (((Byte & 0xAA) >> 1) | ((Byte & 0x55) << 1));
 164
 165                                 return Byte;
 166                         }
 167
 168                         /** Function to reverse the byte ordering of the individual bytes in a 16 bit number.
 169                          *
 170                          *  \ingroup Group_BitManip
 171                          *
 172                          *  \param[in] Word  Word of data whose bytes are to be swapped.
 173                          */
 174                         static inline uint16_t SwapEndian_16(uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 175                         static inline uint16_t SwapEndian_16(uint16_t Word)
 176                         {
 177                                 return ((Word >> 8) | (Word << 8));
 178                         }
 179
 180                         /** Function to reverse the byte ordering of the individual bytes in a 32 bit number.
 181                          *
 182                          *  \ingroup Group_BitManip
 183                          *
 184                          *  \param[in] DWord  Double word of data whose bytes are to be swapped.
 185                          */
 186                         static inline uint32_t SwapEndian_32(uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 187                         static inline uint32_t SwapEndian_32(uint32_t DWord)
 188                         {
 189                                 return (((DWord & 0xFF000000) >> 24) |
 190                                         ((DWord & 0x00FF0000) >> 8)  |
 191                                                 ((DWord & 0x0000FF00) << 8)  |
 192                                                 ((DWord & 0x000000FF) << 24));
 193                         }
 194
 195                         /** Function to reverse the byte ordering of the individual bytes in a n byte number.
 196                          *
 197                          *  \ingroup Group_BitManip
 198                          *
 199                          *  \param[in,out] Data   Pointer to a number containing an even number of bytes to be reversed.
 200                          *  \param[in]     Bytes  Length of the data in bytes.
 201                          */
 202                         static inline void SwapEndian_n(void* Data, uint8_t Bytes);
 203                         static inline void SwapEndian_n(void* Data, uint8_t Bytes)
 204                         {
 205                                 uint8_t* CurrDataPos = (uint8_t*)Data;
 206
 207                                 while (Bytes > 1)
 208                                 {
 209                                         uint8_t Temp = *CurrDataPos;
 210                                         *CurrDataPos = *(CurrDataPos + Bytes - 1);
 211                                         *(CurrDataPos + Bytes - 1) = Temp;
 212
 213                                         CurrDataPos++;
 214                                         Bytes -= 2;
 215                                 }
 216                         }
 217
 218 #endif
 219
 220 /** @} */