Cordic Class Reference

#include <Cordic.h>

Public Member Functions
	Cordic (const uint32_t &aPhiScale, const uint32_t &aMagnitudeBits, const uint32_t &aSteps)
int32_t	IntegerizeMagnitude (const double &aMagnitude)
double	NormalizeMagnitude (const uint32_t &aMagnitude)
double	NormalizePhi (const uint32_t &aPhi)
void	operator() (int32_t aX, int32_t aY, int32_t &aPhi, uint32_t &aMagnitude)
virtual	~Cordic ()

Private Member Functions
uint32_t	tower (const double &aRadians)

Private Attributes
uint32_t	mMagnitudeBits
uint64_t	mMagnitudeRenormalization
uint32_t	mMagnitudeScale
uint32_t	mPhiScale
const double	mPi
std::vector< uint32_t >	mRotations
uint32_t	mSteps

Detailed Description

Definition at line 7 of file Cordic.h.

Constructor & Destructor Documentation

Cordic::Cordic	(	const uint32_t &	aPhiScale,
		const uint32_t &	aMagnitudeBits,
		const uint32_t &	aSteps
	)

Definition at line 9 of file Cordic.cc.

References mMagnitudeRenormalization, mMagnitudeScale, mRotations, mSteps, funct::pow(), mathSSE::sqrt(), and tower().

                                                                                                    : mPhiScale( aPhiScale ) , mMagnitudeScale( 1 << aMagnitudeBits ) , mMagnitudeBits( aMagnitudeBits ) , mSteps( aSteps ) , mPi( 3.1415926535897932384626433832795 )
{
  mRotations.reserve( mSteps );

  double lValue( 1.0 );

  for( uint32_t lStep( 0 ); lStep!=mSteps ; ++lStep ){
    lValue /= sqrt( 1.0 + pow( 4.0 , -double(lStep) ) );
    mRotations.push_back( tower( atan( pow( 2.0 , -double(lStep) ) ) ) );
  }
  mMagnitudeRenormalization = uint32_t( round( mMagnitudeScale * lValue ) );
}

Cordic::~Cordic ( )

virtual

Definition at line 22 of file Cordic.cc.

{}

Member Function Documentation

int32_t Cordic::IntegerizeMagnitude

(

const double &

aMagnitude

)

Definition at line 34 of file Cordic.cc.

References mMagnitudeScale.

{
  return int32_t( aMagnitude * mMagnitudeScale );
}

double Cordic::NormalizeMagnitude

(

const uint32_t &

aMagnitude

)

Definition at line 29 of file Cordic.cc.

References mMagnitudeScale.

{
  return double( aMagnitude ) / double( mMagnitudeScale );
}

double Cordic::NormalizePhi

(

const uint32_t &

aPhi

)

Definition at line 24 of file Cordic.cc.

References mPhiScale.

{
  return double( aPhi ) / double( mPhiScale );
}

void Cordic::operator()	(	int32_t	aX,
		int32_t	aY,
		int32_t &	aPhi,
		uint32_t &	aMagnitude
	)

Definition at line 44 of file Cordic.cc.

References mMagnitudeBits, mMagnitudeRenormalization, mPi, mRotations, mSteps, tower(), globals_cff::x1, and globals_cff::x2.

{
  bool lSign(true);

  switch( ((aY>=0)?0x0:0x2) | ((aX>=0)?0x0:0x1) ){
  case 0:
    aPhi = tower( mPi );
    break;
  case 1:
    aPhi = tower( 2 * mPi );
    lSign = false;
    aX = -aX;
    break;
  case 2:
    aPhi = tower( mPi );
    lSign = false;
    aY = -aY;    
    break;
  case 3:
    aPhi = 0;
    aX = -aX;
    aY = -aY;   
    break;
  default:
    throw 0;
  }

  for( uint32_t lStep( 0 ); lStep!=mSteps ; ++lStep ){
    if ( (aY < 0) == lSign ){
      aPhi -= mRotations[ lStep ];
    }else{    
      aPhi += mRotations[ lStep ];
    }

    int32_t lX(aX), lY(aY);
    if( lY < 0 ){
      aX = lX - (lY >> lStep);
      aY = lY + (lX >> lStep);
    }else{    
      aX = lX + (lY >> lStep);
      aY = lY - (lX >> lStep);
    }
  }

  aMagnitude = (aX * mMagnitudeRenormalization) >> mMagnitudeBits;
}

uint32_t Cordic::tower ( const double &  aRadians )

private

Definition at line 39 of file Cordic.cc.

References mPhiScale, and mPi.

Referenced by Cordic(), and operator()().

{
  return uint32_t( round( mPhiScale * 0.5 * aRadians / mPi ) );
}

Member Data Documentation

uint32_t Cordic::mMagnitudeBits

private

Definition at line 25 of file Cordic.h.

Referenced by operator()().

uint64_t Cordic::mMagnitudeRenormalization

private

Definition at line 27 of file Cordic.h.

Referenced by Cordic(), and operator()().

uint32_t Cordic::mMagnitudeScale

private

Definition at line 24 of file Cordic.h.

Referenced by Cordic(), IntegerizeMagnitude(), and NormalizeMagnitude().

uint32_t Cordic::mPhiScale

private

Definition at line 23 of file Cordic.h.

Referenced by NormalizePhi(), and tower().

const double Cordic::mPi

private

Definition at line 30 of file Cordic.h.

Referenced by operator()(), and tower().

std::vector<uint32_t> Cordic::mRotations

private

Definition at line 28 of file Cordic.h.

Referenced by Cordic(), and operator()().

uint32_t Cordic::mSteps

private

Definition at line 26 of file Cordic.h.

Referenced by Cordic(), and operator()().