RAII class for when you actually need double precision. (MSVC on Win32 w/out /arch:SSE2)

doubleprec.cpp

// header

// RAII class. For use in 32-bit processes compiled without /arch:SSE2 - for
// when you actually need double precision. (D3D and GL like to set x87
// precision to single, which means the only thing you get out of doubles is
// the higher exponent range)
class DoublePrecisionContext
{
    unsigned int oldfp;

public:
    DoublePrecisionContext();
    ~DoublePrecisionContext();
};

// impl

#include <float.h>

DoublePrecisionContext::DoublePrecisionContext()
{
    unsigned int oldfp;
    _controlfp_s(&oldfp, _PC_53, _MCW_PC);
}

DoublePrecisionContext::~DoublePrecisionContext()
{
    _controlfp_s(&oldfp, oldfp, _MCW_PC);
}