compiler/stdc/math/s_frexpf.c

   1 /* s_frexpf.c -- float version of s_frexp.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #ifndef lint
  17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_frexpf.c,v 1.9 2007/06/11 07:48:52 bde Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 static const float
  24 two25 =  3.3554432000e+07; /* 0x4c000000 */
  25
  26 float
  27 frexpf(float x, int *eptr)
  28 {
  29         int32_t hx,ix;
  30         GET_FLOAT_WORD(hx,x);
  31         ix = 0x7fffffff&hx;
  32         *eptr = 0;
  33         if(ix>=0x7f800000||(ix==0)) return x;   /* 0,inf,nan */
  34         if (ix<0x00800000) {            /* subnormal */
  35             x *= two25;
  36             GET_FLOAT_WORD(hx,x);
  37             ix = hx&0x7fffffff;
  38             *eptr = -25;
  39         }
  40         *eptr += (ix>>23)-126;
  41         hx = (hx&0x807fffff)|0x3f000000;
  42         SET_FLOAT_WORD(x,hx);
  43         return x;
  44 }