sysdeps/libm-ieee754/s_modff.c

   1 /* s_modff.c -- float version of s_modf.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_modff.c,v 1.4 1995/05/10 20:47:56 jtc Exp $";
  18 #endif
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22
  23 #ifdef __STDC__
  24 static const float one = 1.0;
  25 #else
  26 static float one = 1.0;
  27 #endif
  28
  29 #ifdef __STDC__
  30         float __modff(float x, float *iptr)
  31 #else
  32         float __modff(x, iptr)
  33         float x,*iptr;
  34 #endif
  35 {
  36         int32_t i0,j0;
  37         u_int32_t i;
  38         GET_FLOAT_WORD(i0,x);
  39         j0 = ((i0>>23)&0xff)-0x7f;      /* exponent of x */
  40         if(j0<23) {                     /* integer part in x */
  41             if(j0<0) {                  /* |x|<1 */
  42                 SET_FLOAT_WORD(*iptr,i0&0x80000000);    /* *iptr = +-0 */
  43                 return x;
  44             } else {
  45                 i = (0x007fffff)>>j0;
  46                 if((i0&i)==0) {                 /* x is integral */
  47                     u_int32_t ix;
  48                     *iptr = x;
  49                     GET_FLOAT_WORD(ix,x);
  50                     SET_FLOAT_WORD(x,ix&0x80000000);    /* return +-0 */
  51                     return x;
  52                 } else {
  53                     SET_FLOAT_WORD(*iptr,i0&(~i));
  54                     return x - *iptr;
  55                 }
  56             }
  57         } else {                        /* no fraction part */
  58             *iptr = x*one;
  59             /* We must handle NaNs separately.  */
  60             if (j0 == 0x80 && (i0 & 0x7fffff))
  61               return x*one;
  62             SET_FLOAT_WORD(x,i0&0x80000000);    /* return +-0 */
  63             return x;
  64         }
  65 }
  66 weak_alias (__modff, modff)