hgmath.h

#if defined(HG_MATH_USE_HGASM)

// nothing

#elif defined(HG_MATH_USE_MSVC_INTRINSICS)

extern "C" double sin(double x);
#pragma intrinsic(sin)

#elif defined(HG_MATH_USE_C)

#include <math.h>
#include <stdlib.h>

#elif defined(HG_MATH_USE_CXX)

#include <cmath>
#include <cstdlib>

#endif

namespace hg {

#if defined(HG_MATH_USE_HGASM)

float sin(float x);

#elif defined(HG_MATH_USE_MSVC_INTRINSICS)

inline float sin(float x) {
	return static_cast<float>(::sin(static_cast<double>(x));
}

#elif defined(HG_MATH_USE_C)

inline float sin(float x) {
	return ::sinf(x);
}

#elif defined(HG_MATH_USE_CXX)

using std::sin;

#endif

} // namespace hg



hgmath.cpp

namespace hg {

#if defined(HG_MATH_USE_HGASM)

float _declspec(naked) hg_sin(float x) {
	__asm {
		fld [esp+4]
		fsin
		ret
	}
};

#endif

} // namespace hg