FPEManager.cpp

#include <FPEManager.hpp>
#include <PastisMacros.hpp>
#include <pastis_config.hpp>
#include <rang.hpp>

#ifdef PASTIS_HAS_FENV_H
#include <fenv.h>

#define MANAGED_FPE (FE_DIVBYZERO|FE_INVALID|FE_OVERFLOW)

#ifdef SYSTEM_IS_DARWIN
// MacOS-X requires definition of feenableexcept and fedisableexcept

// Public domain polyfill for feenableexcept on OS X
// http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c
PASTIS_INLINE
int feenableexcept(unsigned int excepts)
{
  static fenv_t fenv;
  unsigned int new_excepts = excepts & FE_ALL_EXCEPT;
  // previous masks
  unsigned int old_excepts;

  if (fegetenv(&fenv)) {
    return -1;
  }
  old_excepts = fenv.__control & FE_ALL_EXCEPT;

  // unmask
  fenv.__control &= ~new_excepts;
  fenv.__mxcsr   &= ~(new_excepts << 7);

  return fesetenv(&fenv) ? -1 : old_excepts;
}

PASTIS_INLINE
int fedisableexcept(unsigned int excepts)
{
  static fenv_t fenv;
  unsigned int new_excepts = excepts & FE_ALL_EXCEPT;
  // all previous masks
  unsigned int old_excepts;

  if (fegetenv(&fenv)) {
    return -1;
  }
  old_excepts = fenv.__control & FE_ALL_EXCEPT;

  // mask
  fenv.__control |= new_excepts;
  fenv.__mxcsr   |= new_excepts << 7;

  return fesetenv(&fenv) ? -1 : old_excepts;
}

#endif // SYSTEM_IS_DARWIN

void FPEManager::enable()
{
  std::cout << "FE management: "
	    << rang::style::bold
	    << rang::fgB::green
	    << "enabled"
	    << rang::fg::reset
	    << rang::style::reset << '\n';
  ::feenableexcept(MANAGED_FPE);
}

void FPEManager::disable()
{
  std::cout << "FE management: "
	    << rang::style::bold
	    << rang::fgB::red
	    << "disabled"
	    << rang::fg::reset
	    << rang::style::reset << '\n';
  ::fedisableexcept(MANAGED_FPE);
}

#else  // PASTIS_HAS_FENV_H

void FPEManager::enable()
{
  std::cout << "FE management: enabled "
	    << rang::fg::red
	    << "[not supported]"
	    << rang::fg::reset << '\n';
}

void FPEManager::disable()
{
  std::cout << "FE management: disable "
	    << rang::fg::red
	    << "[not supported]"
	    << rang::fg::reset << '\n';
}

#endif // PASTIS_HAS_FENV_H


void FPEManager::init(const bool& enable)
{
  if (enable) {
    FPEManager::enable();
  } else {
    FPEManager::disable();
  }
}