libm/powerpc/s_ldexp.c

   1 /*******************************************************************************
   2 *                                                                              *
   3 *      File frexpldexp.c,                                                      *
   4 *      Functions frexp(x) and ldexp(x),                                        *
   5 *      Implementation of frexp and ldexp functions for the PowerPC.            *
   6 *                                                                              *
   7 *      Copyright © 1991 Apple Computer, Inc.  All rights reserved.             *
   8 *                                                                              *
   9 *      Written by Ali Sazegari, started on January 1991,                       *
  10 *                                                                              *
  11 *      W A R N I N G:  This routine expects a 64 bit double model.             *
  12 *                                                                              *
  13 *      December03 1992: first rs6000 implementation.                           *
  14 *      October 05 1993: added special cases for NaN and ° in frexp.            *
  15 *      May     27 1997: improved the performance of frexp by eliminating the   *
  16 *                       switch statement.                                      *
  17 *        June      13 2001: (ram) rewrote frexp to eliminate calls to scalb and    *
  18 *                               logb.                                                                    *
  19 *                                                                              *
  20 *******************************************************************************/
  21
  22 #include <limits.h>
  23 #include <math.h>
  24 #include <endian.h>
  25
  26 typedef union
  27       {
  28       struct {
  29 #if (__BYTE_ORDER == __BIG_ENDIAN)
  30         unsigned long int hi;
  31         unsigned long int lo;
  32 #else
  33         unsigned long int lo;
  34         unsigned long int hi;
  35 #endif
  36       } words;
  37       double dbl;
  38       } DblInHex;
  39
  40 libm_hidden_proto(ldexp)
  41 double ldexp ( double value, int exp )
  42       {
  43       if ( exp > SHRT_MAX )
  44             exp = SHRT_MAX;
  45       else if ( exp < -SHRT_MAX )
  46             exp = -SHRT_MAX;
  47       return scalb ( value, exp  );
  48       }
  49 libm_hidden_def(ldexp)