sysdeps/sparc/sparc64/soft-fp/s_ilogbl.c

   1 /* Software floating-point emulation.
   2    ilogbl(x, exp)
   3    Copyright (C) 1999 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Jakub Jelinek (jj@ultra.linux.cz).
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 /* ilogbl(long double x)
  23  * return the binary exponent of non-zero x
  24  * ilogbl(0) = 0x80000001
  25  * ilogbl(inf/NaN) = 0x7fffffff (no signal is raised)
  26  */
  27
  28 #include "soft-fp.h"
  29 #include "quad.h"
  30 #include <math.h>
  31
  32 int __ilogbl(long double x)
  33 {
  34   FP_DECL_EX;
  35   FP_DECL_Q(X);
  36
  37 /*
  38   FP_UNPACK_Q(X, x);
  39   switch (X_c)
  40     {
  41     case FP_CLS_ZERO:
  42       return FP_ILOGB0;
  43     case FP_CLS_NAN:
  44     case FP_CLS_INF:
  45       return FP_ILOGBNAN;
  46     default:
  47       return X_e;
  48     }
  49  */
  50   FP_UNPACK_RAW_Q(X, x);
  51   switch (X_e)
  52     {
  53     default:
  54       return X_e - _FP_EXPBIAS_Q;
  55     case 0:
  56 #if (2 * _FP_W_TYPE_SIZE) < _FP_FRACBITS_Q
  57       if (_FP_FRAC_ZEROP_4(X))
  58         return FP_ILOGB0;
  59       else
  60         {
  61           _FP_I_TYPE shift;
  62           _FP_FRAC_CLZ_4(shift, X);
  63           shift -= _FP_FRACXBITS_Q;
  64           return X_e - _FP_EXPBIAS_Q - 1 + shift;
  65         }
  66 #else
  67       if (_FP_FRAC_ZEROP_2(X))
  68         return FP_ILOGB0;
  69       else
  70         {
  71           _FP_I_TYPE shift;
  72           _FP_FRAC_CLZ_2(shift, X);
  73           shift -= _FP_FRACXBITS_Q;
  74           return X_e - _FP_EXPBIAS_Q - 1 + shift;
  75         }
  76 #endif
  77     case _FP_EXPBIAS_Q:
  78       return FP_ILOGBNAN;
  79     }
  80 }
  81
  82 weak_alias (__ilogbl, ilogbl)