torc::bitstream::Spartan6Bitstream::CRC Struct Reference

CRC class for the Spartan6 architecture. More...

#include <Spartan6Bitstream.hpp>

Public Types
enum	{ eLen = 22 }
	Length of the CRC calculation. More...

Public Member Functions
	CRC (void)
	Default constructor. More...
void	reset (void)
	Function to clear the CRC calculation. More...
void	update (uint32_t inAddress, uint32_t inWord)
	Update the CRC with new data. More...
uint8_t &	operator[] (int i)
	Index operator. More...
	operator uint32_t (void) const
	Cast operator to return the CRC as an integer. More...

Data Fields
uint8_t	mBits [eLen]
	CRC calculation bits. More...
uint32_t	mValue
	CRC calculation value. More...

Detailed Description

CRC class for the Spartan6 architecture.

Definition at line 42 of file Spartan6Bitstream.hpp.

Member Enumeration Documentation

anonymous enum

Length of the CRC calculation.

Enumerator
eLen

Definition at line 44 of file Spartan6Bitstream.hpp.

{ eLen = 22 };

Constructor & Destructor Documentation

torc::bitstream::Spartan6Bitstream::CRC::CRC ( void  )

inline

Default constructor.

Definition at line 50 of file Spartan6Bitstream.hpp.

{ reset(); }

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Member Function Documentation

torc::bitstream::Spartan6Bitstream::CRC::operator uint32_t ( void  ) const

inline

Cast operator to return the CRC as an integer.

Definition at line 81 of file Spartan6Bitstream.hpp.

{ return mValue; }

uint8_t& torc::bitstream::Spartan6Bitstream::CRC::operator[] ( int  i )

inline

Index operator.

Definition at line 79 of file Spartan6Bitstream.hpp.

{ return mBits[i]; }

void torc::bitstream::Spartan6Bitstream::CRC::reset ( void  )

inline

Function to clear the CRC calculation.

Definition at line 52 of file Spartan6Bitstream.hpp.

{ for(int32_t i = 0; i < eLen; i++) mBits[i] = 0; mValue = 0; }

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void torc::bitstream::Spartan6Bitstream::CRC::update ( uint32_t  inAddress, uint32_t  inWord  )

inline

Update the CRC with new data.

Definition at line 54 of file Spartan6Bitstream.hpp.

                                                             {
                uint8_t input[eLen];
                uint8_t next[eLen];
                // initialize the input with the current register address and data word
                for(int32_t i = 21, mask = 0x20; i >= 16; i--, mask >>= 1) 
                    input[i] = (inAddress & mask) ? 1 : 0;
                for(int32_t i = 15, mask = 0x8000; i >= 0; i--, mask >>= 1) 
                    input[i] = (inWord & mask) ? 1 : 0;
                // update the CRC
                for(int32_t i = 21; i >= 16; i--) next[i] = mBits[i - 1] ^ input[i];
                next[15] = mBits[14] ^ input[15] ^ mBits[21];
                for(int32_t i = 14; i >= 13; i--) next[i] = mBits[i - 1] ^ input[i];
                next[12] = mBits[11] ^ input[12] ^ mBits[21];
                for(int32_t i = 11; i >= 8; i--) next[i] = mBits[i - 1] ^ input[i];
                next[7] = mBits[6] ^ input[7] ^ mBits[21];
                for(int32_t i = 6; i >= 1; i--) next[i] = mBits[i - 1] ^ input[i];
                next[0] = input[0] ^ mBits[21];
                // copy the updated bits into place
                mValue = 0;
                for(int32_t i = 0, mask = 1; i < eLen; i++, mask <<= 1) {
                    mBits[i] = next[i];
                    mValue |= mBits[i] ? mask : 0;
                }
            }

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Field Documentation

uint8_t torc::bitstream::Spartan6Bitstream::CRC::mBits[eLen]

CRC calculation bits.

Definition at line 46 of file Spartan6Bitstream.hpp.

uint32_t torc::bitstream::Spartan6Bitstream::CRC::mValue

CRC calculation value.

Definition at line 48 of file Spartan6Bitstream.hpp.

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The documentation for this struct was generated from the following file:

• Spartan6Bitstream.hpp