mingw-w64-crt/math/fpclassifyf.c

/**
 * This file has no copyright assigned and is placed in the Public Domain.
 * This file is part of the mingw-w64 runtime package.
 * No warranty is given; refer to the file DISCLAIMER.PD within this package.
 */
#define __CRT__NO_INLINE
#include <math.h>

int __fpclassifyf (float _x)
{
#if defined(__x86_64__) || defined(_AMD64_) || defined(__arm__) || defined(_ARM_) || defined(__aarch64__) || defined(_ARM64_)
    __mingw_flt_type_t hlp;

    hlp.x = _x;
    hlp.val &= 0x7fffffff;
    if (hlp.val == 0)
      return FP_ZERO;
    if (hlp.val < 0x800000)
      return FP_SUBNORMAL;
    if (hlp.val >= 0x7f800000)
      return (hlp.val > 0x7f800000 ? FP_NAN : FP_INFINITE);
    return FP_NORMAL;
#elif defined(__i386__) || defined(_X86_)
  unsigned short sw;
  __asm__ __volatile__ (
	"fxam; fstsw %%ax;"
	: "=a" (sw)
	: "t" (_x)
	);
  return sw & (FP_NAN | FP_NORMAL | FP_ZERO);
#endif
}