sf_fpclassify.c

来自「Newlib 嵌入式 C库 标准实现代码」· C语言 代码 · 共 30 行

/* Copyright (C) 2002,2007 by  Red Hat, Incorporated. All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * is freely granted, provided that this notice is preserved.
 */

#include "fdlibm.h"

int
__fpclassifyf (float x)
{
  __uint32_t w;

  GET_FLOAT_WORD(w,x);
  
  if (w == 0x00000000 || w == 0x80000000)
    return FP_ZERO;
  else if ((w >= 0x00800000 && w <= 0x7f7fffff) ||
           (w >= 0x80800000 && w <= 0xff7fffff))
    return FP_NORMAL;
  else if ((w >= 0x00000001 && w <= 0x007fffff) ||
           (w >= 0x80000001 && w <= 0x807fffff))
    return FP_SUBNORMAL;
  else if (w == 0x7f800000 || w == 0xff800000)
    return FP_INFINITE;
  else
    return FP_NAN;
}