sysdeps/libm-ieee754/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 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: s_frexpf.c,v 1.5 1995/05/10 20:47:26 jtc Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 #ifdef __STDC__
  24 static const float
  25 #else
  26 static float
  27 #endif
  28 two25 =  3.3554432000e+07; /* 0x4c000000 */
  29
  30 #ifdef __STDC__
  31         float __frexpf(float x, int *eptr)
  32 #else
  33         float __frexpf(x, eptr)
  34         float x; int *eptr;
  35 #endif
  36 {
  37         int32_t hx,ix;
  38         GET_FLOAT_WORD(hx,x);
  39         ix = 0x7fffffff&hx;
  40         *eptr = 0;
  41         if(ix>=0x7f800000||(ix==0)) return x;   /* 0,inf,nan */
  42         if (ix<0x00800000) {            /* subnormal */
  43             x *= two25;
  44             GET_FLOAT_WORD(hx,x);
  45             ix = hx&0x7fffffff;
  46             *eptr = -25;
  47         }
  48         *eptr += (ix>>23)-126;
  49         hx = (hx&0x807fffff)|0x3f000000;
  50         *(int*)&x = hx;
  51         return x;
  52 }
  53 weak_alias (__frexpf, frexpf)