clz.cpp File Reference

#include "main.h"

Functions
template<typename T >
int	ref_clz (T val)
template<typename T >
int	ref_ctz (T val)
template<typename T >
void	test_clz_ctz ()
template<typename T >
void	test_clz_ctz_random ()
	EIGEN_DECLARE_TEST (clz)

Function Documentation

EIGEN_DECLARE_TEST()

EIGEN_DECLARE_TEST

(

clz

)

                        {
  CALL_SUBTEST_1(test_clz_ctz<uint8_t>());
  CALL_SUBTEST_2(test_clz_ctz<uint16_t>());
  CALL_SUBTEST_3(test_clz_ctz<uint32_t>());
  CALL_SUBTEST_4(test_clz_ctz<uint64_t>());
 
  for (int i = 0; i < g_repeat; i++) {
    test_clz_ctz_random<uint32_t>();
    test_clz_ctz_random<uint64_t>();
  }
}

References CALL_SUBTEST_1, CALL_SUBTEST_2, CALL_SUBTEST_3, CALL_SUBTEST_4, Eigen::g_repeat, and i.

ref_clz()

template<typename T >

int ref_clz

(

T

val

)

                   {
  constexpr int kNumBits = sizeof(T) * CHAR_BIT;
  T kMsbMask = T(1) << (kNumBits - 1);
  int z = 0;
  for (; z < kNumBits && ((val & kMsbMask) == 0); ++z) {
    val <<= 1;
  }
  return z;
}

References calibrate::val.

Referenced by test_clz_ctz(), and test_clz_ctz_random().

ref_ctz()

template<typename T >

int ref_ctz

(

T

val

)

                   {
  constexpr int kNumBits = sizeof(T) * CHAR_BIT;
  T kLsbMask = T(1);
  int z = 0;
  for (; z < kNumBits && ((val & kLsbMask) == 0); ++z) {
    val >>= 1;
  }
  return z;
}

References calibrate::val.

Referenced by test_clz_ctz(), and test_clz_ctz_random().

test_clz_ctz()

template<typename T >

void test_clz_ctz

(

)

                    {
  T step = sizeof(T) <= 2 ? 1 : (Eigen::NumTraits<T>::highest() / (T(1) << 16));
  T iters = Eigen::NumTraits<T>::highest() / step;
  for (T i = 0; i < iters; ++i) {
    T val = i * step;
    int expected_clz = ref_clz(val);
    int actual_clz = Eigen::internal::clz(val);
    VERIFY(expected_clz == actual_clz);
 
    int expected_ctz = ref_ctz(val);
    int actual_ctz = Eigen::internal::ctz(val);
    VERIFY(expected_ctz == actual_ctz);
  }
}

References Eigen::internal::clz(), Eigen::internal::ctz(), i, ref_clz(), ref_ctz(), calibrate::val, and VERIFY.

test_clz_ctz_random()

template<typename T >

void test_clz_ctz_random

(

)

                           {
  for (int i = 0; i < 1024 * 1024; ++i) {
    T val = Eigen::internal::random<T>();
    int expected_clz = ref_clz(val);
    int actual_clz = Eigen::internal::clz(val);
    VERIFY(expected_clz == actual_clz);
 
    int expected_ctz = ref_ctz(val);
    int actual_ctz = Eigen::internal::ctz(val);
    VERIFY(expected_ctz == actual_ctz);
  }
}

References Eigen::internal::clz(), Eigen::internal::ctz(), i, ref_clz(), ref_ctz(), calibrate::val, and VERIFY.