[binutils.git] / gdb / rdi-share / crc.c

/* 
 * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
 * 
 * This software may be freely used, copied, modified, and distributed
 * provided that the above copyright notice is preserved in all copies of the
 * software.
 */

/* -*-C-*-
 *
 * $Revision$
 *     $Date$
 *
 *
 * crc.c - provides some "standard" CRC calculation routines.
 *
 */
#include "crc.h"    /* describes this code */

/**********************************************************************/

/*
 * crc32                                                IEEE-802.3 32bit CRC
 * -----                                                --------------------
 */

/* This table was generated by the "crctable" program */
static const unsigned int crc32table[256] = {
                   /* 0x00 */ 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
                   /* 0x04 */ 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
                   /* 0x08 */ 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
                   /* 0x0C */ 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
                   /* 0x10 */ 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
                   /* 0x14 */ 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
                   /* 0x18 */ 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
                   /* 0x1C */ 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
                   /* 0x20 */ 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
                   /* 0x24 */ 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
                   /* 0x28 */ 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
                   /* 0x2C */ 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
                   /* 0x30 */ 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
                   /* 0x34 */ 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
                   /* 0x38 */ 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
                   /* 0x3C */ 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
                   /* 0x40 */ 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
                   /* 0x44 */ 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
                   /* 0x48 */ 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
                   /* 0x4C */ 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
                   /* 0x50 */ 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
                   /* 0x54 */ 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
                   /* 0x58 */ 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
                   /* 0x5C */ 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
                   /* 0x60 */ 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
                   /* 0x64 */ 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
                   /* 0x68 */ 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
                   /* 0x6C */ 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
                   /* 0x70 */ 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
                   /* 0x74 */ 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
                   /* 0x78 */ 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
                   /* 0x7C */ 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
                   /* 0x80 */ 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
                   /* 0x84 */ 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
                   /* 0x88 */ 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
                   /* 0x8C */ 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
                   /* 0x90 */ 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
                   /* 0x94 */ 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
                   /* 0x98 */ 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
                   /* 0x9C */ 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
                   /* 0xA0 */ 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
                   /* 0xA4 */ 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
                   /* 0xA8 */ 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
                   /* 0xAC */ 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
                   /* 0xB0 */ 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
                   /* 0xB4 */ 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
                   /* 0xB8 */ 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
                   /* 0xBC */ 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
                   /* 0xC0 */ 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
                   /* 0xC4 */ 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
                   /* 0xC8 */ 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
                   /* 0xCC */ 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
                   /* 0xD0 */ 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
                   /* 0xD4 */ 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
                   /* 0xD8 */ 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
                   /* 0xDC */ 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
                   /* 0xE0 */ 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
                   /* 0xE4 */ 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
                   /* 0xE8 */ 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
                   /* 0xEC */ 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
                   /* 0xF0 */ 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
                   /* 0xF4 */ 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
                   /* 0xF8 */ 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
                   /* 0xFC */ 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
                                            };
unsigned int crc32(unsigned char *address, unsigned int size, unsigned int crc)
{
#if 0
  /* FAST, but bigger and only good for word-aligned data */
  unsigned int *daddr = (unsigned int *)address;
  unsigned int  data = FALSE; /* little-endian by default */

 /*
  * TODO: We should really get the current processor big- or
  * little-endian state and set "data" accordingly.
  */

  /* Perform word loop to save on memory accesses */
  if (data)
    /* big-endian */
    for (; (size > 0); size -= sizeof(unsigned int))
    {
      data = *daddr++;
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >> 24) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >> 16) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >>  8) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >>  0) & 0xFF)) & 0xFF]);
    }
  else
    for (; (size > 0); size -= sizeof(unsigned int))
    {
      data = *daddr++;
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >>  0) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >>  8) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >> 16) & 0xFF)) & 0xFF]);
      crc = (((crc >> 8) & 0x00FFFFFF) ^
             crc32table[(crc ^ ((data >> 24) & 0xFF)) & 0xFF]);
    }
#else
  for (; (size > 0); size--)
    /* byte loop */
    crc = (((crc >> 8) & 0x00FFFFFF) ^
           crc32table[(crc ^ *address++) & 0x000000FF]);
#endif

  return(crc);
}

/**********************************************************************/

/*
 * crc16                                                     16bit CRC-CCITT
 * -----                                                     ---------------
 * This function provides a table driven 16bit CRC generation for byte data.
 * This CRC is also known as the HDLC CRC.
 */
/*
 * 960201 KWelton
 *
 *TODO: Is this correct?  The compiler predefines __arm, *not* __ARM
 */
#ifdef __ARM
/*
 * To make the code quicker on the ARM, we double the table size and
 * use integer slots rather than short slots for the table.
 */
static const unsigned int crctableA[16] = {
#else
static const unsigned short crctableA[16] = {
#endif
                                             0x0000,
                                             0x1081,
                                             0x2102,
                                             0x3183,
                                             0x4204,
                                             0x5285,
                                             0x6306,
                                             0x7387,
                                             0x8408,
                                             0x9489,
                                             0xA50A,
                                             0xB58B,
                                             0xC60C,
                                             0xD68D,
                                             0xE70E,
                                             0xF78F
                                            };

#ifdef __ARM
/* See comments above */
static const unsigned int crctableB[16] = {
#else
static const unsigned short crctableB[16] = {
#endif
                                             0x0000,
                                             0x1189,
                                             0x2312,
                                             0x329B,
                                             0x4624,
                                             0x57AD,
                                             0x6536,
                                             0x74BF,
                                             0x8C48,
                                             0x9DC1,
                                             0xAF5A,
                                             0xBED3,
                                             0xCA6C,
                                             0xDBE5,
                                             0xE97E,
                                             0xF8F7
                                            };

unsigned short crc16(unsigned char *address, unsigned int size,
                     unsigned short crc)
{
  for (; (size > 0); size--)
  {
    /* byte loop */
    unsigned char data = *address++; /* fetch the next data byte */

    data ^= crc; /* EOR data with current CRC value */
    crc = ((crctableA[(data & 0xF0) >> 4] ^ crctableB[data & 0x0F]) ^
           (crc >> 8));
  }

  return(crc);
}

/**********************************************************************/

#if 0 /* not required at the moment */

/*
 * elf_hash
 * --------
 * This function is derived from the one on page 68 of chapter of the "Unix
 * SVR4 Programmer's Guide". It is used to generate a hash-code from a
 * symbol name.
 */
unsigned int elf_hash(const unsigned char *name)
{
  unsigned int h = 0;
  unsigned int g;

  /* NULL pointer returns a hash of zero */
  while (name && (*name))
  {
    h = ((h << 4) + *name++);

    if (g = (h & 0xF0000000))
      h ^= (g >> 24);

    h &= ~g;
  }

  return(h);
}
#endif

/**********************************************************************/

/* EOF crc.c */
Commit	Line	Data
3a9c3d12 NC	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.c - provides some "standard" CRC calculation routines.
	16	*
	17	*/
	18	#include "crc.h" /* describes this code */
	19
	20	/**********************************************************************/
	21
	22	/*
	23	* crc32 IEEE-802.3 32bit CRC
	24	* ----- --------------------
	25	*/
	26
	27	/* This table was generated by the "crctable" program */
	28	static const unsigned int crc32table[256] = {
	29	/* 0x00 */ 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
	30	/* 0x04 */ 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
	31	/* 0x08 */ 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
	32	/* 0x0C */ 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
	33	/* 0x10 */ 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
	34	/* 0x14 */ 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
	35	/* 0x18 */ 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
	36	/* 0x1C */ 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
	37	/* 0x20 */ 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
	38	/* 0x24 */ 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
	39	/* 0x28 */ 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
	40	/* 0x2C */ 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
	41	/* 0x30 */ 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
	42	/* 0x34 */ 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
	43	/* 0x38 */ 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
	44	/* 0x3C */ 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
	45	/* 0x40 */ 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
	46	/* 0x44 */ 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
	47	/* 0x48 */ 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
	48	/* 0x4C */ 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
	49	/* 0x50 */ 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
	50	/* 0x54 */ 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
	51	/* 0x58 */ 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
	52	/* 0x5C */ 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
	53	/* 0x60 */ 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
	54	/* 0x64 */ 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
	55	/* 0x68 */ 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
	56	/* 0x6C */ 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
	57	/* 0x70 */ 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
	58	/* 0x74 */ 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
	59	/* 0x78 */ 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
	60	/* 0x7C */ 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
	61	/* 0x80 */ 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
	62	/* 0x84 */ 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
	63	/* 0x88 */ 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
	64	/* 0x8C */ 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
65	/* 0x90 */ 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
66	/* 0x94 */ 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
67	/* 0x98 */ 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
68	/* 0x9C */ 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
69	/* 0xA0 */ 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
70	/* 0xA4 */ 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
71	/* 0xA8 */ 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
72	/* 0xAC */ 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
73	/* 0xB0 */ 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
74	/* 0xB4 */ 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
75	/* 0xB8 */ 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
76	/* 0xBC */ 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
77	/* 0xC0 */ 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
78	/* 0xC4 */ 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
79	/* 0xC8 */ 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
80	/* 0xCC */ 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
81	/* 0xD0 */ 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
82	/* 0xD4 */ 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
83	/* 0xD8 */ 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
84	/* 0xDC */ 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
85	/* 0xE0 */ 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
86	/* 0xE4 */ 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
87	/* 0xE8 */ 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
88	/* 0xEC */ 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
89	/* 0xF0 */ 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
90	/* 0xF4 */ 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
91	/* 0xF8 */ 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
92	/* 0xFC */ 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
93	};
94	unsigned int crc32(unsigned char *address, unsigned int size, unsigned int crc)
95	{
96	#if 0
97	/* FAST, but bigger and only good for word-aligned data */
98	unsigned int daddr = (unsigned int )address;
99	unsigned int data = FALSE; /* little-endian by default */
100
101	/*
102	* TODO: We should really get the current processor big- or
103	* little-endian state and set "data" accordingly.
104	*/
105
106	/* Perform word loop to save on memory accesses */
107	if (data)
108	/* big-endian */
109	for (; (size > 0); size -= sizeof(unsigned int))
110	{
111	data = *daddr++;
112	crc = (((crc >> 8) & 0x00FFFFFF) ^
113	crc32table[(crc ^ ((data >> 24) & 0xFF)) & 0xFF]);
114	crc = (((crc >> 8) & 0x00FFFFFF) ^
115	crc32table[(crc ^ ((data >> 16) & 0xFF)) & 0xFF]);
116	crc = (((crc >> 8) & 0x00FFFFFF) ^
117	crc32table[(crc ^ ((data >> 8) & 0xFF)) & 0xFF]);
118	crc = (((crc >> 8) & 0x00FFFFFF) ^
119	crc32table[(crc ^ ((data >> 0) & 0xFF)) & 0xFF]);
120	}
121	else
122	for (; (size > 0); size -= sizeof(unsigned int))
123	{
124	data = *daddr++;
125	crc = (((crc >> 8) & 0x00FFFFFF) ^
126	crc32table[(crc ^ ((data >> 0) & 0xFF)) & 0xFF]);
127	crc = (((crc >> 8) & 0x00FFFFFF) ^
128	crc32table[(crc ^ ((data >> 8) & 0xFF)) & 0xFF]);
129	crc = (((crc >> 8) & 0x00FFFFFF) ^
130	crc32table[(crc ^ ((data >> 16) & 0xFF)) & 0xFF]);
131	crc = (((crc >> 8) & 0x00FFFFFF) ^
132	crc32table[(crc ^ ((data >> 24) & 0xFF)) & 0xFF]);
133	}
134	#else
135	for (; (size > 0); size--)
136	/* byte loop */
137	crc = (((crc >> 8) & 0x00FFFFFF) ^
138	crc32table[(crc ^ *address++) & 0x000000FF]);
139	#endif
140
141	return(crc);
142	}
143
144	/**********************************************************************/
145
146	/*
147	* crc16 16bit CRC-CCITT
148	* ----- ---------------
149	* This function provides a table driven 16bit CRC generation for byte data.
150	* This CRC is also known as the HDLC CRC.
151	*/
152	/*
153	* 960201 KWelton
154	*
155	TODO: Is this correct? The compiler predefines __arm, not* __ARM
156	*/
157	#ifdef __ARM
158	/*
159	* To make the code quicker on the ARM, we double the table size and
160	* use integer slots rather than short slots for the table.
161	*/
162	static const unsigned int crctableA[16] = {
163	#else
164	static const unsigned short crctableA[16] = {
165	#endif
166	0x0000,
167	0x1081,
168	0x2102,
169	0x3183,
170	0x4204,
171	0x5285,
172	0x6306,
173	0x7387,
174	0x8408,
175	0x9489,
176	0xA50A,
177	0xB58B,
178	0xC60C,
179	0xD68D,
180	0xE70E,
181	0xF78F
182	};
183
184	#ifdef __ARM
185	/* See comments above */
186	static const unsigned int crctableB[16] = {
187	#else
188	static const unsigned short crctableB[16] = {
189	#endif
190	0x0000,
191	0x1189,
192	0x2312,
193	0x329B,
194	0x4624,
195	0x57AD,
196	0x6536,
197	0x74BF,
198	0x8C48,
199	0x9DC1,
200	0xAF5A,
201	0xBED3,
202	0xCA6C,
203	0xDBE5,
204	0xE97E,
205	0xF8F7
206	};
207
208	unsigned short crc16(unsigned char *address, unsigned int size,
209	unsigned short crc)
210	{
211	for (; (size > 0); size--)
212	{
213	/* byte loop */
214	unsigned char data = address++; / fetch the next data byte */
215
216	data ^= crc; /* EOR data with current CRC value */
217	crc = ((crctableA[(data & 0xF0) >> 4] ^ crctableB[data & 0x0F]) ^
218	(crc >> 8));
219	}
220
221	return(crc);
222	}
223
224	/**********************************************************************/
225
226	#if 0 /* not required at the moment */
227
228	/*
229	* elf_hash
230	* --------
231	* This function is derived from the one on page 68 of chapter of the "Unix
232	* SVR4 Programmer's Guide". It is used to generate a hash-code from a
233	* symbol name.
234	*/
235	unsigned int elf_hash(const unsigned char *name)
236	{
237	unsigned int h = 0;
238	unsigned int g;
239
240	/* NULL pointer returns a hash of zero */
241	while (name && (*name))
242	{
243	h = ((h << 4) + *name++);
244
245	if (g = (h & 0xF0000000))
246	h ^= (g >> 24);
247
248	h &= ~g;
249	}
250
251	return(h);
252	}
253	#endif
254
255	/**********************************************************************/
256
257	/* EOF crc.c */