approx_math.h

Go to the documentation of this file.

#ifndef DataFormatsMathApproxMath_H
#define DataFormatsMathApproxMath_H


#include <cstdint>
#include <cmath>
#include <limits>
#include <algorithm>

namespace approx_math {
  // not c++ compliant (only C compliant)
  // to be c++ compliaint one must use memcpy...
  union binary32 {
    constexpr binary32() : ui32(0) {};
    constexpr binary32(float ff) : f(ff) {};
    constexpr binary32(int32_t ii) : i32(ii){}
    constexpr binary32(uint32_t ui) : ui32(ui){}
    
    uint32_t ui32; /* unsigned int */                
    int32_t i32; /* Signed int */                
    float f;
  };
#ifdef __SSE4_1__
  constexpr float fpfloor(float x) {
    return std::floor(x);
  }
#else
  constexpr float fpfloor(float x) {
    int32_t ret = x;
    binary32 xx(x);
    ret-=(xx.ui32>>31);  
    return ret;
  }
#endif
}

#endif