gdb/rdi-share/crc.h

   1 /*
   2  * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
   3  *
   4  * This software may be freely used, copied, modified, and distributed
   5  * provided that the above copyright notice is preserved in all copies of the
   6  * software.
   7  */
   8
   9 /* -*-C-*-
  10  *
  11  * $Revision$
  12  *     $Date$
  13  *
  14  *
  15  * crc.h - describes some "standard" CRC calculation routines.
  16  */
  17 #ifndef angel_crc_h
  18 #define angel_crc_h
  19
  20 /*
  21  * manifests
  22  */
  23
  24 /*
  25  * When using "crc32" or "crc16" these initial CRC values must be given to
  26  * the respective function the first time it is called. The function can
  27  * then be called with the return value from the last call of the function
  28  * to generate a running CRC over multiple data blocks.
  29  * When the last data block has been processed using the "crc32" algorithm
  30  * the CRC value should be inverted to produce the final CRC value:
  31  * e.g. CRC = ~CRC
  32  */
  33
  34 #define startCRC32  (0xFFFFFFFF)    /* CRC initialised to all 1s */
  35 #define startCRC16  (0x0000)        /* CRC initialised to all 0s */
  36
  37 /*
  38  * For the CRC-32 residual to be calculated correctly requires that the CRC
  39  * value is in memory little-endian due to the byte read, bit-ordering
  40  * nature of the algorithm.
  41  */
  42 #define CRC32residual   (0xDEBB20E3)    /* good CRC-32 residual */
  43
  44
  45 /**********************************************************************/
  46
  47 /*
  48  * exported functions
  49  */
  50
  51 /*
  52  *  Function: crc32
  53  *   Purpose: Provides a table driven implementation of the IEEE-802.3
  54  *            32-bit CRC algorithm for byte data.
  55  *
  56  *    Params:
  57  *       Input: address     pointer to the byte data
  58  *              size        number of bytes of data to be processed
  59  *              crc         initial CRC value to be used (can be the output
  60  *                          from a previous call to this function).
  61  *   Returns:
  62  *          OK: 32-bit CRC value for the specified data
  63  */
  64 extern unsigned int crc32(unsigned char *address, unsigned int size,
  65                           unsigned int crc);
  66
  67 /**********************************************************************/
  68
  69 /*
  70  *
  71  *  Function: crc16
  72  *   Purpose: Generates a table driven 16-bit CRC-CCITT for byte data
  73  *
  74  *    Params:
  75  *       Input: address     pointer to the byte data
  76  *              size        number of bytes of data to be processed
  77  *              crc         initial CRC value to be used (can be the output
  78  *                          from a previous call to this function).
  79  *
  80  *   Returns:
  81  *          OK: 16-bit CRC value for the specified data
  82  */
  83 extern unsigned short crc16(unsigned char *address, unsigned int size,
  84                             unsigned short crc);
  85
  86 /**********************************************************************/
  87
  88 #endif /* !defined(angel_crc_h) */
  89
  90 /* EOF crc.h */