newlib/libm/common/sf_modf.c

   1 /* sf_modf.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 #include "fdlibm.h"
  17
  18 #ifdef __STDC__
  19         float modff(float x, float *iptr)
  20 #else
  21         float modff(x, iptr)
  22         float x,*iptr;
  23 #endif
  24 {
  25         __int32_t i0,j0;
  26         __uint32_t i;
  27         GET_FLOAT_WORD(i0,x);
  28         j0 = ((i0>>23)&0xff)-0x7f;      /* exponent of x */
  29         if(j0<23) {                     /* integer part in x */
  30             if(j0<0) {                  /* |x|<1 */
  31                 SET_FLOAT_WORD(*iptr,i0&0x80000000);    /* *iptr = +-0 */
  32                 return x;
  33             } else {
  34                 i = (0x007fffff)>>j0;
  35                 if((i0&i)==0) {                 /* x is integral */
  36                     *iptr = x;
  37                     SET_FLOAT_WORD(x,i0&0x80000000);    /* return +-0 */
  38                     return x;
  39                 } else {
  40                     SET_FLOAT_WORD(*iptr,i0&(~i));
  41                     return x - *iptr;
  42                 }
  43             }
  44         } else {                        /* no fraction part */
  45             *iptr = x;
  46             if (__fpclassifyf(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
  47             SET_FLOAT_WORD(x,i0&0x80000000);    /* return +-0 */
  48             return x;
  49         }
  50 }
  51
  52 #ifdef _DOUBLE_IS_32BITS
  53
  54 #ifdef __STDC__
  55         double modf(double x, double *iptr)
  56 #else
  57         double modf(x, iptr)
  58         double x,*iptr;
  59 #endif
  60 {
  61         return (double) modff((float) x, (float *) iptr);
  62 }
  63
  64 #endif /* defined(_DOUBLE_IS_32BITS) */