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) const
double	NormalizeMagnitude (const uint32_t &aMagnitude) const
double	NormalizePhi (const uint32_t &aPhi) const
void	operator() (int32_t aX, int32_t aY, int32_t &aPhi, uint32_t &aMagnitude) const
virtual	~Cordic ()

Private Member Functions
uint32_t	tower (const double &aRadians) const

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 26 of file Cordic.cc.

{}

Member Function Documentation

int32_t Cordic::IntegerizeMagnitude

(

const double &

aMagnitude

)

const

Definition at line 34 of file Cordic.cc.

References mMagnitudeScale.

{ return int32_t(aMagnitude * mMagnitudeScale); }

double Cordic::NormalizeMagnitude

(

const uint32_t &

aMagnitude

)

const

Definition at line 30 of file Cordic.cc.

References mMagnitudeScale.

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

double Cordic::NormalizePhi

(

const uint32_t &

aPhi

)

const

Definition at line 28 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
	)		const

Definition at line 38 of file Cordic.cc.

References mMagnitudeBits, mMagnitudeRenormalization, mPi, mRotations, mSteps, and tower().

                                                                                         {
  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 ) const

private

Definition at line 36 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 24 of file Cordic.h.

Referenced by operator()().

uint64_t Cordic::mMagnitudeRenormalization

private

Definition at line 26 of file Cordic.h.

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

uint32_t Cordic::mMagnitudeScale

private

Definition at line 23 of file Cordic.h.

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

uint32_t Cordic::mPhiScale

private

Definition at line 22 of file Cordic.h.

Referenced by NormalizePhi(), and tower().

const double Cordic::mPi

private

Definition at line 29 of file Cordic.h.

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

std::vector<uint32_t> Cordic::mRotations

private

Definition at line 27 of file Cordic.h.

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

uint32_t Cordic::mSteps

private

Definition at line 25 of file Cordic.h.

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