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GLAST / LAT > DAQ and FSW > FSW > Doxygen Index> EDS / V2-10-2 > edsprint / mv2304

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EBF_tkr.c File Reference

Utility routines to partially parse the tracker data. More...

#include "EDS/EBF_tkr.h"
#include "EDS/FFS.h"

Defines
#define	BITCOUNT(x)   (((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)
	Computes the number of bits set (1) in 32-bit argument.
#define	BX_(x)
	Replaces each 4-bit sequence in arg by the number of bits in sequence.
Functions
static __inline int	countLayerEnds (const unsigned int accepts[3])
	Counts the number of layer ends with data in the accept block.
int	EBF_tkrLayerEndCount (const EBF_tkr *tkr)
	Counts the number of layer ends with hit strips.
int	EBF_tkrStripCount (const EBF_tkr *tkr, int layerEndCnt, int maxwrds)
	Counts the hit strips.
int	EBF_tkrLenCalc (const EBF_tkr *tkr, int maxwrds)
	Calculates the number of bytes, not including any padding, in the EBF_tkr record.

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Detailed Description

Utility routines to partially parse the tracker data.

Author:

JJRussell - russell@slac.stanford.edu

    CVS $Id: EBF_tkr.c,v 1.2 2005/10/13 22:00:58 russell Exp $

The tracker data is particularly hard to parse. One must serially decode the data. In many cases, one is not interested in a full unpacking, merely overall quantities, such as the TKR data length, the number of hit strips, etc. These routines provide as fast as possible method to do this.

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Define Documentation

#define BITCOUNT

(

x

)

(((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)

Computes the number of bits set (1) in 32-bit argument.

See also:

BX_

Credit to Chris Smith (original algorithm) Jane Huffman (original writer) Brad Merril & Jerry Leichter (ported from 36-bit words to 32-bit words)

#define BX_

(

x

)

Value:

((x) - (((x)>>1)&0x77777777)                    \
                             - (((x)>>2)&0x33333333)                    \
                             - (((x)>>3)&0x11111111))

Replaces each 4-bit sequence in arg by the number of bits in sequence.

See also:

BITCOUNT

Replaces each 4-bit sequence in 32-bit argument by the number of bits in that sequence (which will, of course, fit in 4 bits).

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Function Documentation

int countLayerEnds

(

const unsigned int

accepts[3]

)

[static]

Counts the number of layer ends with data in the accept block.

Returns:

The number of layer ends with data in the accept block

Parameters:

accepts

The array of the 3 accept words (only 72 bits active)

int EBF_tkrLayerEndCount

(

const EBF_tkr *

tkr

)

Counts the number of layer ends with hit strips.

Returns:

The number of layer ends with hit strips

Parameters:

tkr

Pointer to the tracker data

int EBF_tkrLenCalc	(	const EBF_tkr *	tkr,
		int	maxwrds
	)

Calculates the number of bytes, not including any padding, in the EBF_tkr record.

Returns:

The byte length of the active information in the EBF_tkr record

Parameters:

	tkr	Pointer to the tracker data
	maxwrds	The maximum number of words that can possibly be in the EBF_tkr record. This serves as a sanity check in case the serial decode of the record goes haywire.

This function must serially parse the entire TKR record for a given tower and, is, therefore, is not cheap, particularly in the case of large EBF_tkr records. If one needs both the number of layers hit, the strip count and the length of the record, it is better to use EBF_tkrLayerEndCnt and EBF_tkrStripCnt and compute the length from these values. Note that if the diagnostic block and/or the error block is present, the lengths of these blocks need to be added in.

int EBF_tkrStripCount	(	const EBF_tkr *	tkr,
		int	layerEndCnt,
		int	maxwrds
	)

Counts the hit strips.

Returns:

The number hit strips

Parameters:

	tkr	Pointer to the tracker data
	layerEndCnt	Count of the number hit layer end ends. This is most easily acquired from EBF_tkrLayerEndCount.
	maxwrds	The maximum number of words in the TKR record. This value is currently not used, but may be used in the future as an integrity check.

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