__fpclassifyf.c

#include <math.h>
#include <stdint.h>

short __cdecl _fdclass(float x)
{
	union {float f; uint32_t i;} u = {x};
	int e = u.i>>23 & 0xff;
	if (!e) return u.i<<1 ? FP_SUBNORMAL : FP_ZERO;
	if (e==0xff) return u.i<<9 ? FP_NAN : FP_INFINITE;
	return FP_NORMAL;
}