📄 crc.h
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#ifndef CRC_H
#define CRC_H
/*===========================================================================
C R C S E R V I C E S D E C L A R A T I O N S
DESCRIPTION
The following declarations are for use with the CRC Services.
Copyright(c) 1991,1992,1996 by QUALCOMM, Incorporated. All Rights Reserved.
Copyright(c) 1998,1999 by QUALCOMM, Incorporated. All Rights Reserved.
===========================================================================*/
/*===========================================================================
EDIT HISTORY FOR FILE
This section contains comments describing changes made to this file.
Notice that changes are listed in reverse chronological order.
$PVCSPath: O:/src/asw/COMMON/vcs/crc.h_v 1.2 28 Aug 2002 14:35:54 ldefauw $
$Header: //depot/asic/msmshared/services/common/crc.h#3 $ $DateTime: 2002/08/28 14:35:48 $ $Author: ldefauw $
when who what, where, why
-------- --- ----------------------------------------------------------
11/29/01 lad Added step-wise CRC30 calculation.
03/17/99 ms Removed comments related to bb_ for Virtual Boot Block.
12/16/98 jct Removed 80186 support
09/21/98 jct Incorporate ARM porting changes, cdecl changes
02/28/96 dna Changed crc_16_l_table extern to be a pointer so the
macro now accesses the table through the Boot Block jump
table.
06/21/93 jah Corrected CRC_16_L_OK to match with crc_16_l_calc().
06/07/93 jah Added prototype for crc_16_l_calc(), and improved comments
for CRC_16_L_STEP().
04/26/93 jah Added extern for crc_16_l_table[] for macro.
04/22/93 jah Added CRC definitions and macro to support CRC CCITT-16
processed LSB first.
07/09/92 jah Changed crc_16_step() from bits to bytes
06/18/92 jah Ported from brassboard and converted to table-driven.
===========================================================================*/
#include "comdef.h"
/*===========================================================================
DATA DECLARATIONS
===========================================================================*/
/* Residual CRC value to compare against return value of crc_16_calc().
** Use crc_16_calc() to calculate a 16 bit CRC, and append it to the buffer.
** When crc_16_calc() is applied to the unchanged result, it returns CRC_16_OK.
*/
#define CRC_16_OK 0xE2F0
/* Mask for CRC-16 polynomial:
**
** x^16 + x^12 + x^5 + 1
**
** This is more commonly referred to as CCITT-16.
** Note: the x^16 tap is left off, it's implicit.
*/
#define CRC_16_POLYNOMIAL 0x1021
/* Seed value for CRC register. The all ones seed is part of CCITT-16, as
** well as allows detection of an entire data stream of zeroes.
*/
#define CRC_16_SEED 0xFFFF
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Seed value for CRC register. The all zeroes seed is inverted prior to
** being used in the step-wise CRC CCITT-16. This behaves as CRC_16_SEED.
*/
#define CRC_16_STEP_SEED (~((word) CRC_16_SEED))
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Residual CRC value to compare against return value of crc_30_calc().
** Use crc_30_calc() to calculate a 30 bit CRC, and append it to the buffer.
** When crc_30_calc() is applied to the unchanged result, it returns CRC_30_OK.
*/
#define CRC_30_OK 0x0B105AA5
/* Mask for CRC-30 polynomial:
**
** x^30+x^29+x^21+x^20+x^15+x^13+x^12+x^11+x^8+x^7+x^6+x^2+x^1+1
**
** Note: the x^30 tap is left off, it's implicit.
*/
#define CRC_30_POLYNOMIAL 0x6030B9C7
/* Seed value for CRC register. The all ones seed allows detection of
** an entire data stream of zeroes.
*/
#define CRC_30_SEED 0x3FFFFFFF
/* Seed value for CRC30 register. The CRC30 seed is inverted prior to
** being used in the step-wise CRC-30. This behaves as CRC_30_SEED.
*/
#define CRC_30_STEP_SEED (~((dword) CRC_30_SEED))
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Mask for CRC-16 polynomial:
**
** x^16 + x^12 + x^5 + 1
**
** This is more commonly referred to as CCITT-16.
** Note: the x^16 tap is left off, it's implicit.
*/
#define CRC_16_L_POLYNOMIAL 0x8408
/* Seed value for CRC register. The all ones seed is part of CCITT-16, as
** well as allows detection of an entire data stream of zeroes.
*/
#define CRC_16_L_SEED 0xFFFF
/* Seed value for CRC register. The all ones seed is inverted prior to
** being used in the step-wise CRC CCITT-16. This behaves as CRC_16_L_SEED.
*/
#define CRC_16_L_STEP_SEED ((word) ~((word) CRC_16_L_SEED))
/* Residual CRC value to compare against return value of a CRC_16_L_STEP().
** Use CRC_16_L_STEP() to calculate a 16 bit CRC, complement the result,
** and append it to the buffer. When CRC_16_L_STEP() is applied to the
** unchanged entire buffer, and complemented, it returns CRC_16_L_OK.
** Crc_16_l_calc() of the same entire buffer returns CRC_16_L_OK.
*/
#define CRC_16_L_OK 0x0F47
/*===========================================================================
MACRO CRC_16_L_STEP
DESCRIPTION
This function calculates one byte step of an LSB-first 16-bit CRC over
a specified number of data bits. It can be used to produce a CRC and
to check a CRC.
PARAMETERS
xx_crc Current value of the CRC calculation, 16-bits
xx_c New byte to figure into the CRC, 8-bits
DEPENDENCIES
None
RETURN VALUE
The new CRC value, 16-bits. If this macro is being used to check a
CRC, and is run over a range of bytes, the return value will be equal
to CRC_16_L_OK (defined in crc.h) if the CRC checks correctly. When
generating a CRC to be appended to such a range of bytes, the final
result must be XOR'd with CRC_16_L_SEED before being appended.
SIDE EFFECTS
xx_crc is evaluated twice within this macro.
===========================================================================*/
/* crc_16_l_table is a pointer in the Boot Block jump table which
** points to the actual table crc_16_l_table
*/
extern const word crc_16_l_table[]; /* Extern for macro (global) */
#define CRC_16_L_STEP(xx_crc,xx_c) \
(((xx_crc) >> 8) ^ crc_16_l_table[((xx_crc) ^ (xx_c)) & 0x00ff])
/*===========================================================================
FUNCTION DECLARATIONS
===========================================================================*/
/*===========================================================================
FUNCTION CRC_16_CALC
DESCRIPTION
This function calculates a 16-bit CRC over a specified number of data
bits. It can be used to produce a CRC and to check a CRC.
DEPENDENCIES
None
RETURN VALUE
Returns a word holding 16 bits which are the contents of the CRC
register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_16_OK (defined in crc.h) if the CRC checks correctly.
SIDE EFFECTS
None
===========================================================================*/
extern word crc_16_calc
(
byte *buf_ptr,
/* Pointer to bytes containing the data to CRC. The bit stream starts
** in the MS bit of the first byte.
*/
word len
/* Number of data bits to calculate the CRC over */
);
/*===========================================================================
FUNCTION CRC_16_L_CALC
DESCRIPTION
This function calculates an LSB-first 16-bit CRC over a specified number
of data bits. It can be used to produce a CRC and to check a CRC.
DEPENDENCIES
None
RETURN VALUE
Returns a word holding 16 bits which are the contents of the CRC
register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_16_L_OK (defined in crc.h) if the CRC checks correctly.
SIDE EFFECTS
None
===========================================================================*/
extern word crc_16_l_calc
(
byte *buf_ptr,
/* Pointer to bytes containing the data to CRC. The bit stream starts
** in the LS bit of the first byte.
*/
word len
/* Number of data bits to calculate the CRC over */
);
/*===========================================================================
FUNCTION CRC_30_CALC
DESCRIPTION
This function calculates a 30-bit CRC over a specified number of data
bits. It can be used to produce a CRC and to check a CRC.
DEPENDENCIES
None
RETURN VALUE
Returns a double word holding 30 bits which are the contents of the
CRC register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_30_OK (defined in crc.h) if the CRC checks correctly.
SIDE EFFECTS
None
===========================================================================*/
extern dword crc_30_calc
(
byte *buf_ptr,
/* Pointer to bytes containing the data to CRC. The bit stream starts
** in the MS bit of the first byte.
*/
word len
/* Number of data bits to calculate the CRC over */
);
/*===========================================================================
FUNCTION CRC_30_STEP
DESCRIPTION
This function calculates a 30-bit CRC over a specified number of data
bits. It can be used to produce a CRC and to check a CRC. The CRC value
passed in is used to continue the CRC calculation from a previous call,
this allows this routine to be used to CRC discontinuous data.
DEPENDENCIES
None
RETURN VALUE
Returns a double word holding 30 bits which are the contents of the
CRC register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_30_OK (defined in crc.h) if the CRC checks correctly.
NOTE: The caller is expected to mask the bottom 30 bits from the value,
SIDE EFFECTS
None
===========================================================================*/
extern dword crc_30_step
(
dword seed,
/* Either the result of a previous crc_30_step() or CRC_16_STEP_SEED
** the first time the routine is called. Note that the input is
** inverted prior to use, to counteract the inversion applied when
** it was returned as a result of the previous step.
*/
byte *buf_ptr,
/* Pointer to bytes containing the data to CRC. The bit stream starts
** in the MS bit of the first byte.
*/
word len
/* Number of data bits to calculate the CRC over */
);
/*===========================================================================
FUNCTION CRC_16_STEP
DESCRIPTION
This function calculates a 16-bit CRC over a specified number of data
bits. It can be used to produce a CRC and to check a CRC. The CRC value
passed in is used to continue the CRC calculation from a previous call,
this allows this routine to be used to CRC discontinuous data.
DEPENDENCIES
None
RETURN VALUE
Returns a word holding 16 bits which are the contents of the CRC
register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_16_OK (defined in crc.h) if the CRC checks correctly.
SIDE EFFECTS
None
===========================================================================*/
extern word crc_16_step
(
word seed,
/* Either the result of a previous crc_16_step() or CRC_16_STEP_SEED
** the first time the routine is called. Note that the input is
** inverted prior to use, to counteract the inversion applied when
** it was returned as a result of the previous step.
*/
byte *buf_ptr,
/* Pointer to bytes containing the data to CRC. The bit stream starts
** in the MS bit of the first byte.
*/
word byte_len
/* Number of data bytes to calculate the CRC over */
);
/*===========================================================================
FUNCTION CRC_16_L_STEP
DESCRIPTION
This function calculates a LSB-first 16-bit CRC over a specified number
of data bytes. It can be used to produce a CRC and to check a CRC.
The CRC value passed in is used to continue the CRC calculation from a
previous call; this allows this routine to be used to CRC discontinuous data.
DEPENDENCIES
None
RETURN VALUE
Returns a word holding 16 bits which are the contents of the CRC
register as calculated over the specified data bits. If this
function is being used to check a CRC, then the return value will be
equal to CRC_16_OK (defined in crc.h) if the CRC checks correctly.
SIDE EFFECTS
None
===========================================================================*/
word crc_16_l_step
(
word seed,
const void *buf_ptr,
/* Either the result of a previous crc_16_l_step() or CRC_16_L_STEP_SEED
** the first time the routine is called. Note that the input is
** inverted prior to use, to counteract the inversion applied when
** it was returned as a result of the previous step.
*/
unsigned int byte_len
/* Number of data bytes to calculate the CRC over */
);
#endif /* CRC_H */
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