1b725ae77Skettenis /* 2b725ae77Skettenis * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved. 3b725ae77Skettenis * 4b725ae77Skettenis * This software may be freely used, copied, modified, and distributed 5b725ae77Skettenis * provided that the above copyright notice is preserved in all copies of the 6b725ae77Skettenis * software. 7b725ae77Skettenis */ 8b725ae77Skettenis 9b725ae77Skettenis /* -*-C-*- 10b725ae77Skettenis * 11*63addd46Skettenis * $Revision: 1.3 $ 12*63addd46Skettenis * $Date: 2004/12/27 14:00:54 $ 13b725ae77Skettenis * 14b725ae77Skettenis * 15b725ae77Skettenis * crc.h - describes some "standard" CRC calculation routines. 16b725ae77Skettenis */ 17b725ae77Skettenis #ifndef angel_crc_h 18b725ae77Skettenis #define angel_crc_h 19b725ae77Skettenis 20b725ae77Skettenis /* 21b725ae77Skettenis * manifests 22b725ae77Skettenis */ 23b725ae77Skettenis 24b725ae77Skettenis /* 25b725ae77Skettenis * When using "crc32" or "crc16" these initial CRC values must be given to 26b725ae77Skettenis * the respective function the first time it is called. The function can 27b725ae77Skettenis * then be called with the return value from the last call of the function 28b725ae77Skettenis * to generate a running CRC over multiple data blocks. 29b725ae77Skettenis * When the last data block has been processed using the "crc32" algorithm 30b725ae77Skettenis * the CRC value should be inverted to produce the final CRC value: 31b725ae77Skettenis * e.g. CRC = ~CRC 32b725ae77Skettenis */ 33b725ae77Skettenis 34b725ae77Skettenis #define startCRC32 (0xFFFFFFFF) /* CRC initialised to all 1s */ 35b725ae77Skettenis #define startCRC16 (0x0000) /* CRC initialised to all 0s */ 36b725ae77Skettenis 37b725ae77Skettenis /* 38b725ae77Skettenis * For the CRC-32 residual to be calculated correctly requires that the CRC 39b725ae77Skettenis * value is in memory little-endian due to the byte read, bit-ordering 40b725ae77Skettenis * nature of the algorithm. 41b725ae77Skettenis */ 42b725ae77Skettenis #define CRC32residual (0xDEBB20E3) /* good CRC-32 residual */ 43b725ae77Skettenis 44b725ae77Skettenis 45b725ae77Skettenis /**********************************************************************/ 46b725ae77Skettenis 47b725ae77Skettenis /* 48b725ae77Skettenis * exported functions 49b725ae77Skettenis */ 50b725ae77Skettenis 51b725ae77Skettenis /* 52b725ae77Skettenis * Function: crc32 53b725ae77Skettenis * Purpose: Provides a table driven implementation of the IEEE-802.3 54b725ae77Skettenis * 32-bit CRC algorithm for byte data. 55b725ae77Skettenis * 56b725ae77Skettenis * Params: 57b725ae77Skettenis * Input: address pointer to the byte data 58b725ae77Skettenis * size number of bytes of data to be processed 59b725ae77Skettenis * crc initial CRC value to be used (can be the output 60b725ae77Skettenis * from a previous call to this function). 61b725ae77Skettenis * Returns: 62b725ae77Skettenis * OK: 32-bit CRC value for the specified data 63b725ae77Skettenis */ 64b725ae77Skettenis extern unsigned int crc32(unsigned char *address, unsigned int size, 65b725ae77Skettenis unsigned int crc); 66b725ae77Skettenis 67b725ae77Skettenis /**********************************************************************/ 68b725ae77Skettenis 69b725ae77Skettenis /* 70b725ae77Skettenis * 71b725ae77Skettenis * Function: crc16 72b725ae77Skettenis * Purpose: Generates a table driven 16-bit CRC-CCITT for byte data 73b725ae77Skettenis * 74b725ae77Skettenis * Params: 75b725ae77Skettenis * Input: address pointer to the byte data 76b725ae77Skettenis * size number of bytes of data to be processed 77b725ae77Skettenis * crc initial CRC value to be used (can be the output 78b725ae77Skettenis * from a previous call to this function). 79b725ae77Skettenis * 80b725ae77Skettenis * Returns: 81b725ae77Skettenis * OK: 16-bit CRC value for the specified data 82b725ae77Skettenis */ 83b725ae77Skettenis extern unsigned short crc16(unsigned char *address, unsigned int size, 84b725ae77Skettenis unsigned short crc); 85b725ae77Skettenis 86b725ae77Skettenis /**********************************************************************/ 87b725ae77Skettenis 88b725ae77Skettenis #endif /* !defined(angel_crc_h) */ 89b725ae77Skettenis 90b725ae77Skettenis /* EOF crc.h */ 91