code-stellarator-optimization/include/sctl/intrin_wrapper.hpp

#ifndef _SCTL_INTRIN_WRAPPER_HPP_
#define _SCTL_INTRIN_WRAPPER_HPP_

#include SCTL_INCLUDE(math_utils.hpp)
#include SCTL_INCLUDE(common.hpp)
#include <cstdint>

#ifdef __SSE__
#include <xmmintrin.h>
#endif
#ifdef __SSE2__
#include <emmintrin.h>
#endif
#ifdef __SSE3__
#include <pmmintrin.h>
#endif
#ifdef __AVX__
#include <immintrin.h>
#endif
#if defined(__MIC__)
#include <immintrin.h>
#endif

// TODO: Check alignment when SCTL_MEMDEBUG is defined
// TODO: Replace pointers with iterators

namespace SCTL_NAMESPACE {

template <class T> inline T zero_intrin() { return (T)0; }

template <class T, class Real> inline T set_intrin(const Real& a) { return a; }

template <class T, class Real> inline T load_intrin(Real const* a) { return a[0]; }

template <class T, class Real> inline T bcast_intrin(Real const* a) { return a[0]; }

template <class T, class Real> inline void store_intrin(Real* a, const T& b) { a[0] = b; }

template <class T> inline T mul_intrin(const T& a, const T& b) { return a * b; }

template <class T> inline T add_intrin(const T& a, const T& b) { return a + b; }

template <class T> inline T sub_intrin(const T& a, const T& b) { return a - b; }

template <class T> inline T cmplt_intrin(const T& a, const T& b) {
  T r = 0;
  uint8_t* r_ = reinterpret_cast<uint8_t*>(&r);
  if (a < b)
    for (int i = 0; i < (int)sizeof(T); i++) r_[i] = ~(uint8_t)0;
  return r;
}

template <class T> inline T and_intrin(const T& a, const T& b) {
  T r = 0;
  const uint8_t* a_ = reinterpret_cast<const uint8_t*>(&a);
  const uint8_t* b_ = reinterpret_cast<const uint8_t*>(&b);
  uint8_t* r_ = reinterpret_cast<uint8_t*>(&r);
  for (int i = 0; i < (int)sizeof(T); i++) r_[i] = a_[i] & b_[i];
  return r;
}

template <class T> inline T rsqrt_approx_intrin(const T& r2) {
  if (r2 != 0) return 1.0 / sqrt<T>(r2);
  return 0;
}

template <class T, class Real> inline void rsqrt_newton_intrin(T& rinv, const T& r2, const Real& nwtn_const) { rinv = rinv * (nwtn_const - r2 * rinv * rinv); }

template <class T> inline T rsqrt_single_intrin(const T& r2) {
  if (r2 != 0) return 1.0 / sqrt<T>(r2);
  return 0;
}

template <class T> inline T max_intrin(const T& a, const T& b) {
  if (a > b)
    return a;
  else
    return b;
}

template <class T> inline T min_intrin(const T& a, const T& b) {
  if (a > b)
    return b;
  else
    return a;
}

template <class T> inline T sin_intrin(const T& t) { return sin<T>(t); }

template <class T> inline T cos_intrin(const T& t) { return cos<T>(t); }

#ifdef __SSE3__
template <> inline __m128 zero_intrin() { return _mm_setzero_ps(); }

template <> inline __m128d zero_intrin() { return _mm_setzero_pd(); }

template <> inline __m128 set_intrin(const float& a) { return _mm_set1_ps(a); }

template <> inline __m128d set_intrin(const double& a) { return _mm_set1_pd(a); }

template <> inline __m128 load_intrin(float const* a) { return _mm_load_ps(a); }

template <> inline __m128d load_intrin(double const* a) { return _mm_load_pd(a); }

template <> inline __m128 bcast_intrin(float const* a) { return _mm_set1_ps(a[0]); }

template <> inline __m128d bcast_intrin(double const* a) { return _mm_load1_pd(a); }

template <> inline void store_intrin(float* a, const __m128& b) { return _mm_store_ps(a, b); }

template <> inline void store_intrin(double* a, const __m128d& b) { return _mm_store_pd(a, b); }

template <> inline __m128 mul_intrin(const __m128& a, const __m128& b) { return _mm_mul_ps(a, b); }

template <> inline __m128d mul_intrin(const __m128d& a, const __m128d& b) { return _mm_mul_pd(a, b); }

template <> inline __m128 add_intrin(const __m128& a, const __m128& b) { return _mm_add_ps(a, b); }

template <> inline __m128d add_intrin(const __m128d& a, const __m128d& b) { return _mm_add_pd(a, b); }

template <> inline __m128 sub_intrin(const __m128& a, const __m128& b) { return _mm_sub_ps(a, b); }

template <> inline __m128d sub_intrin(const __m128d& a, const __m128d& b) { return _mm_sub_pd(a, b); }

template <> inline __m128 cmplt_intrin(const __m128& a, const __m128& b) { return _mm_cmplt_ps(a, b); }

template <> inline __m128d cmplt_intrin(const __m128d& a, const __m128d& b) { return _mm_cmplt_pd(a, b); }

template <> inline __m128 and_intrin(const __m128& a, const __m128& b) { return _mm_and_ps(a, b); }

template <> inline __m128d and_intrin(const __m128d& a, const __m128d& b) { return _mm_and_pd(a, b); }

template <> inline __m128 rsqrt_approx_intrin(const __m128& r2) {
  // Approx inverse square root which returns zero for r2=0
  return _mm_andnot_ps(_mm_cmpeq_ps(r2, zero_intrin<__m128>()), _mm_rsqrt_ps(r2));
}

template <> inline __m128d rsqrt_approx_intrin(const __m128d& r2) {
  return _mm_cvtps_pd(rsqrt_approx_intrin(_mm_cvtpd_ps(r2)));
}

template <> inline void rsqrt_newton_intrin(__m128& rinv, const __m128& r2, const float& nwtn_const) {
  // Newton iteration: rinv = 0.5 rinv_approx ( 3 - r2 rinv_approx^2 )
  // We do not compute the product with 0.5 and this needs to be adjusted later
  rinv = mul_intrin(rinv, sub_intrin(set_intrin<__m128>(nwtn_const), mul_intrin(r2, mul_intrin(rinv, rinv))));
}

template <> inline void rsqrt_newton_intrin(__m128d& rinv, const __m128d& r2, const double& nwtn_const) {
  // Newton iteration: rinv = 0.5 rinv_approx ( 3 - r2 rinv_approx^2 )
  // We do not compute the product with 0.5 and this needs to be adjusted later
  rinv = mul_intrin(rinv, sub_intrin(set_intrin<__m128d>(nwtn_const), mul_intrin(r2, mul_intrin(rinv, rinv))));
}

template <> inline __m128 rsqrt_single_intrin(const __m128& r2) {
  __m128 rinv = rsqrt_approx_intrin(r2);
  rsqrt_newton_intrin(rinv, r2, (float)3.0);
  return rinv;
}

template <> inline __m128d rsqrt_single_intrin(const __m128d& r2) {
  return _mm_cvtps_pd(rsqrt_single_intrin(_mm_cvtpd_ps(r2)));
}

template <> inline __m128 max_intrin(const __m128& a, const __m128& b) { return _mm_max_ps(a, b); }

template <> inline __m128d max_intrin(const __m128d& a, const __m128d& b) { return _mm_max_pd(a, b); }

template <> inline __m128 min_intrin(const __m128& a, const __m128& b) { return _mm_min_ps(a, b); }

template <> inline __m128d min_intrin(const __m128d& a, const __m128d& b) { return _mm_min_pd(a, b); }

#ifdef SCTL_HAVE_INTEL_SVML
template <> inline __m128 sin_intrin(const __m128& t) { return _mm_sin_ps(t); }

template <> inline __m128 cos_intrin(const __m128& t) { return _mm_cos_ps(t); }

template <> inline __m128d sin_intrin(const __m128d& t) { return _mm_sin_pd(t); }

template <> inline __m128d cos_intrin(const __m128d& t) { return _mm_cos_pd(t); }
#else
template <> inline __m128 sin_intrin(const __m128& t_) {
  union {
    float e[4];
    __m128 d;
  } t;
  store_intrin(t.e, t_);
  return _mm_set_ps(sin<float>(t.e[3]), sin<float>(t.e[2]), sin<float>(t.e[1]), sin<float>(t.e[0]));
}

template <> inline __m128 cos_intrin(const __m128& t_) {
  union {
    float e[4];
    __m128 d;
  } t;
  store_intrin(t.e, t_);
  return _mm_set_ps(cos<float>(t.e[3]), cos<float>(t.e[2]), cos<float>(t.e[1]), cos<float>(t.e[0]));
}

template <> inline __m128d sin_intrin(const __m128d& t_) {
  union {
    double e[2];
    __m128d d;
  } t;
  store_intrin(t.e, t_);
  return _mm_set_pd(sin<double>(t.e[1]), sin<double>(t.e[0]));
}

template <> inline __m128d cos_intrin(const __m128d& t_) {
  union {
    double e[2];
    __m128d d;
  } t;
  store_intrin(t.e, t_);
  return _mm_set_pd(cos<double>(t.e[1]), cos<double>(t.e[0]));
}
#endif
#endif

#ifdef __AVX__
template <> inline __m256 zero_intrin() { return _mm256_setzero_ps(); }

template <> inline __m256d zero_intrin() { return _mm256_setzero_pd(); }

template <> inline __m256 set_intrin(const float& a) { return _mm256_set1_ps(a); }

template <> inline __m256d set_intrin(const double& a) { return _mm256_set1_pd(a); }

template <> inline __m256 load_intrin(float const* a) { return _mm256_load_ps(a); }

template <> inline __m256d load_intrin(double const* a) { return _mm256_load_pd(a); }

template <> inline __m256 bcast_intrin(float const* a) { return _mm256_broadcast_ss(a); }

template <> inline __m256d bcast_intrin(double const* a) { return _mm256_broadcast_sd(a); }

template <> inline void store_intrin(float* a, const __m256& b) { return _mm256_store_ps(a, b); }

template <> inline void store_intrin(double* a, const __m256d& b) { return _mm256_store_pd(a, b); }

template <> inline __m256 mul_intrin(const __m256& a, const __m256& b) { return _mm256_mul_ps(a, b); }

template <> inline __m256d mul_intrin(const __m256d& a, const __m256d& b) { return _mm256_mul_pd(a, b); }

template <> inline __m256 add_intrin(const __m256& a, const __m256& b) { return _mm256_add_ps(a, b); }

template <> inline __m256d add_intrin(const __m256d& a, const __m256d& b) { return _mm256_add_pd(a, b); }

template <> inline __m256 sub_intrin(const __m256& a, const __m256& b) { return _mm256_sub_ps(a, b); }

template <> inline __m256d sub_intrin(const __m256d& a, const __m256d& b) { return _mm256_sub_pd(a, b); }

template <> inline __m256 cmplt_intrin(const __m256& a, const __m256& b) { return _mm256_cmp_ps(a, b, _CMP_LT_OS); }

template <> inline __m256d cmplt_intrin(const __m256d& a, const __m256d& b) { return _mm256_cmp_pd(a, b, _CMP_LT_OS); }

template <> inline __m256 and_intrin(const __m256& a, const __m256& b) { return _mm256_and_ps(a, b); }

template <> inline __m256d and_intrin(const __m256d& a, const __m256d& b) { return _mm256_and_pd(a, b); }

template <> inline __m256 rsqrt_approx_intrin(const __m256& r2) {
  // Approx inverse square root which returns zero for r2=0
  return _mm256_andnot_ps(_mm256_cmp_ps(r2, zero_intrin<__m256>(), _CMP_EQ_OS), _mm256_rsqrt_ps(r2));
}

template <> inline __m256d rsqrt_approx_intrin(const __m256d& r2) {
  return _mm256_cvtps_pd(rsqrt_approx_intrin(_mm256_cvtpd_ps(r2)));
}

template <> inline void rsqrt_newton_intrin(__m256& rinv, const __m256& r2, const float& nwtn_const) {
  // Newton iteration: rinv = 0.5 rinv_approx ( 3 - r2 rinv_approx^2 )
  // We do not compute the product with 0.5 and this needs to be adjusted later
  rinv = mul_intrin(rinv, sub_intrin(set_intrin<__m256>(nwtn_const), mul_intrin(r2, mul_intrin(rinv, rinv))));
}

template <> inline void rsqrt_newton_intrin(__m256d& rinv, const __m256d& r2, const double& nwtn_const) {
  // Newton iteration: rinv = 0.5 rinv_approx ( 3 - r2 rinv_approx^2 )
  // We do not compute the product with 0.5 and this needs to be adjusted later
  rinv = mul_intrin(rinv, sub_intrin(set_intrin<__m256d>(nwtn_const), mul_intrin(r2, mul_intrin(rinv, rinv))));
}

template <> inline __m256 rsqrt_single_intrin(const __m256& r2) {
  __m256 rinv = rsqrt_approx_intrin(r2);
  rsqrt_newton_intrin(rinv, r2, (float)3.0);
  return rinv;
}

template <> inline __m256d rsqrt_single_intrin(const __m256d& r2) {
  return _mm256_cvtps_pd(rsqrt_single_intrin(_mm256_cvtpd_ps(r2)));
}

template <> inline __m256 max_intrin(const __m256& a, const __m256& b) { return _mm256_max_ps(a, b); }

template <> inline __m256d max_intrin(const __m256d& a, const __m256d& b) { return _mm256_max_pd(a, b); }

template <> inline __m256 min_intrin(const __m256& a, const __m256& b) { return _mm256_min_ps(a, b); }

template <> inline __m256d min_intrin(const __m256d& a, const __m256d& b) { return _mm256_min_pd(a, b); }

#ifdef SCTL_HAVE_INTEL_SVML
template <> inline __m256 sin_intrin(const __m256& t) { return _mm256_sin_ps(t); }

template <> inline __m256 cos_intrin(const __m256& t) { return _mm256_cos_ps(t); }

template <> inline __m256d sin_intrin(const __m256d& t) { return _mm256_sin_pd(t); }

template <> inline __m256d cos_intrin(const __m256d& t) { return _mm256_cos_pd(t); }
#else
template <> inline __m256 sin_intrin(const __m256& t_) {
  union {
    float e[8];
    __m256 d;
  } t;
  store_intrin(t.e, t_);  // t.d=t_;
  return _mm256_set_ps(sin<float>(t.e[7]), sin<float>(t.e[6]), sin<float>(t.e[5]), sin<float>(t.e[4]), sin<float>(t.e[3]), sin<float>(t.e[2]), sin<float>(t.e[1]), sin<float>(t.e[0]));
}

template <> inline __m256 cos_intrin(const __m256& t_) {
  union {
    float e[8];
    __m256 d;
  } t;
  store_intrin(t.e, t_);  // t.d=t_;
  return _mm256_set_ps(cos<float>(t.e[7]), cos<float>(t.e[6]), cos<float>(t.e[5]), cos<float>(t.e[4]), cos<float>(t.e[3]), cos<float>(t.e[2]), cos<float>(t.e[1]), cos<float>(t.e[0]));
}

template <> inline __m256d sin_intrin(const __m256d& t_) {
  union {
    double e[4];
    __m256d d;
  } t;
  store_intrin(t.e, t_);  // t.d=t_;
  return _mm256_set_pd(sin<double>(t.e[3]), sin<double>(t.e[2]), sin<double>(t.e[1]), sin<double>(t.e[0]));
}

template <> inline __m256d cos_intrin(const __m256d& t_) {
  union {
    double e[4];
    __m256d d;
  } t;
  store_intrin(t.e, t_);  // t.d=t_;
  return _mm256_set_pd(cos<double>(t.e[3]), cos<double>(t.e[2]), cos<double>(t.e[1]), cos<double>(t.e[0]));
}
#endif
#endif

template <class VEC, class Real> inline VEC rsqrt_intrin0(VEC r2) {
  VEC rinv;
  rinv = rsqrt_approx_intrin(r2);
  return rinv;
}

template <class VEC, class Real> inline VEC rsqrt_intrin1(VEC r2) {
  Real const_nwtn1 = 3;

  VEC rinv;
  rinv = rsqrt_approx_intrin(r2);
  rsqrt_newton_intrin(rinv, r2, const_nwtn1);
  return rinv;
}

template <class VEC, class Real> inline VEC rsqrt_intrin2(VEC r2) {
  Real const_nwtn1 = 3;
  Real const_nwtn2 = 12;

  VEC rinv;
  rinv = rsqrt_approx_intrin(r2);
  rsqrt_newton_intrin(rinv, r2, const_nwtn1);
  rsqrt_newton_intrin(rinv, r2, const_nwtn2);
  return rinv;
}

template <class VEC, class Real> inline VEC rsqrt_intrin3(VEC r2) {
  Real const_nwtn1 = 3;
  Real const_nwtn2 = 12;
  Real const_nwtn3 = 768;

  VEC rinv = rsqrt_approx_intrin(r2);
  rsqrt_newton_intrin(rinv, r2, const_nwtn1);
  rsqrt_newton_intrin(rinv, r2, const_nwtn2);
  rsqrt_newton_intrin(rinv, r2, const_nwtn3);
  return rinv;
}
}

#endif  //_SCTL_INTRIN_WRAPPER_HPP_