LUFA/Common/Common.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   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  *
  33  *  This file contains macros which are common to all library elements, and which may be useful in user code. It
  34  *  also includes other common headees, such as Atomic.h, FunctionAttributes.h and BoardTypes.h.
  35  */
  36
  37 #ifndef __COMMON_H__
  38 #define __COMMON_H__
  39
  40         /* Includes: */
  41                 #include <avr/io.h>
  42                 #include <stdio.h>
  43                 #include <avr/version.h>
  44
  45                 #include "FunctionAttributes.h"
  46                 #include "BoardTypes.h"
  47
  48                 #include <alloca.h>
  49
  50         /* Public Interface - May be used in end-application: */
  51                 /* Macros: */
  52                         /** Macro for encasing other multi-statment macros. This should be used along with an opening brace
  53                          *  before the start of any multi-statement macro, so that the macros contents as a whole are treated
  54                          *  as a discreete block and not as a list of seperate statements which may cause problems when used as
  55                          *  a block (such as inline IF statments).
  56                          */
  57                         #define MACROS                  do
  58
  59                         /** Macro for encasing other multi-statment macros. This should be used along with a preceeding closing
  60                          *  brace at the end of any multi-statement macro, so that the macros contents as a whole are treated
  61                          *  as a discreete block and not as a list of seperate statements which may cause problems when used as
  62                          *  a block (such as inline IF statments).
  63                          */
  64                         #define MACROE                  while (0)
  65
  66                         /** Defines a volatile NOP statment which cannot be optimized out by the compiler, and thus can always
  67                          *  be set as a breakpoint in the resulting code. Useful for debugging purposes, where the optimizer
  68                          *  removes/reorders code to the point where break points cannot reliably be set.
  69                          */
  70                         #define JTAG_DEBUG_POINT()      asm volatile ("NOP" ::)
  71
  72                         /** Defines an explicit JTAG break point in the resulting binary via the ASM BREAK statment. When
  73                          *  a JTAG is used, this causes the program execution to halt when reached until manually resumed. */
  74                         #define JTAG_DEBUG_BREAK()      asm volatile ("BREAK" ::)
  75
  76                         /** Macro for testing condition "x" and breaking via JTAG_DEBUG_BREAK() if the condition is false. */
  77                         #define JTAG_DEBUG_ASSERT(x)    MACROS{ if (!(x)) { JTAG_DEBUG_BREAK(); } }MACROE
  78
  79                         /** Macro for testing condition "x" and writing debug data to the serial stream if false. As a
  80                          *  prerequisite for this macro, the serial stream should be configured via the Serial_Stream driver.
  81                          *
  82                          *  The serial output takes the form "{FILENAME}: Function {FUNCTION NAME}, Line {LINE NUMBER}: Assertion
  83                          *  {x} failed."
  84                          */
  85                         #define SERIAL_STREAM_ASSERT(x) MACROS{ if (!(x)) { printf_P(PSTR("%s: Function \"%s\", Line %d: "   \
  86                                                                                                                                 "Assertion \"%s\" failed.\r\n"),   \
  87                                                                                                                                 __FILE__, __func__, __LINE__, #x); \
  88                                                         } }MACROE
  89
  90                 /* Inline Functions: */
  91                         /** Function for reliably setting the AVR's system clock prescaler, using inline assembly. This function
  92                          *  is guaranteed to operate reliably regardless of optimization setting or other compile time options.
  93                          *
  94                          *  \param PrescalerMask   The mask of the new prescaler setting for CLKPR
  95                          */
  96                         static inline void SetSystemClockPrescaler(uint8_t PrescalerMask)
  97                         {
  98                                         uint8_t tmp = (1 << CLKPCE);
  99                                         __asm__ __volatile__ (
 100                                                         "in __tmp_reg__,__SREG__" "\n\t"
 101                                                         "cli" "\n\t"
 102                                                         "sts %1, %0" "\n\t"
 103                                                         "sts %1, %2" "\n\t"
 104                                                         "out __SREG__, __tmp_reg__"
 105                                                         : /* no outputs */
 106                                                         : "d" (tmp),
 107                                                           "M" (_SFR_MEM_ADDR(CLKPR)),
 108                                                           "d" (PrescalerMask)
 109                                                         : "r0");
 110                         }
 111
 112                         /** Function to reverse the individual bits in a byte - i.e. bit 7 is moved to bit 0, bit 6 to bit 1,
 113                          *  etc.
 114                          *
 115                          *  \param Byte   Byte of data whose bits are to be reversed
 116                          */
 117                         static inline uint8_t BitReverse(uint8_t Byte) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 118                         static inline uint8_t BitReverse(uint8_t Byte)
 119                         {
 120                                 Byte = (((Byte & 0xF0) >> 4) | ((Byte & 0x0F) << 4));
 121                                 Byte = (((Byte & 0xCC) >> 2) | ((Byte & 0x33) << 2));
 122                                 Byte = (((Byte & 0xAA) >> 1) | ((Byte & 0x55) << 1));
 123
 124                                 return Byte;
 125                         }
 126
 127                         /** Function to reverse the byte ordering of the individual bytes in a 16 bit number.
 128                          *
 129                          *  \param Word   Word of data whose bytes are to be swapped
 130                          */
 131                         static inline uint16_t SwapEndian_16(uint16_t Word) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 132                         static inline uint16_t SwapEndian_16(uint16_t Word)
 133                         {
 134                                 return ((Word >> 8) | (Word << 8));
 135                         }
 136
 137                         /** Function to reverse the byte ordering of the individual bytes in a 32 bit number.
 138                          *
 139                          *  \param DWord   Double word of data whose bytes are to be swapped
 140                          */
 141                         static inline uint32_t SwapEndian_32(uint32_t DWord) ATTR_WARN_UNUSED_RESULT ATTR_CONST;
 142                         static inline uint32_t SwapEndian_32(uint32_t DWord)
 143                         {
 144                                 return (((DWord & 0xFF000000) >> 24) |
 145                                         ((DWord & 0x00FF0000) >> 8)  |
 146                                                 ((DWord & 0x0000FF00) << 8)  |
 147                                                 ((DWord & 0x000000FF) << 24));
 148                         }
 149
 150                         /** Function to reverse the byte ordering of the individual bytes in a n byte number.
 151                          *
 152                          *  \param Data   Pointer to a number containing an even number of bytes to be reversed
 153                          *  \param Bytes  Length of the data in bytes
 154                          */
 155                         static inline void SwapEndian_n(uint8_t* Data, uint8_t Bytes);
 156                         static inline void SwapEndian_n(uint8_t* Data, uint8_t Bytes)
 157                         {
 158                                 uint8_t Temp;
 159
 160                                 while (Bytes)
 161                                 {
 162                                         Temp = *Data;
 163                                         *Data = *(Data + Bytes - 1);
 164                                         *(Data + Bytes) = Temp;
 165
 166                                         Data++;
 167                                         Bytes -= 2;
 168                                 }
 169                         }
 170
 171 #endif