sysdeps/ieee754/ldbl-128ibm/s_fpclassifyl.c

   1 /* Return classification value corresponding to argument.
   2    Copyright (C) 1997-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20
  21 #include <math_private.h>
  22 #include <math_ldbl_opt.h>
  23
  24   /*
  25    *            hx                  lx
  26    * +NaN       7ffn nnnn nnnn nnnn xxxx xxxx xxxx xxxx
  27    * -NaN       fffn nnnn nnnn nnnn xxxx xxxx xxxx xxxx
  28    * +Inf       7ff0 0000 0000 0000 xxxx xxxx xxxx xxxx
  29    * -Inf       fff0 0000 0000 0000 xxxx xxxx xxxx xxxx
  30    * +0         0000 0000 0000 0000 xxxx xxxx xxxx xxxx
  31    * -0         8000 0000 0000 0000 xxxx xxxx xxxx xxxx
  32    * +normal    0360 0000 0000 0000 0000 0000 0000 0000 (smallest)
  33    * -normal    8360 0000 0000 0000 0000 0000 0000 0000 (smallest)
  34    * +normal    7fef ffff ffff ffff 7c8f ffff ffff fffe (largest)
  35    * +normal    ffef ffff ffff ffff fc8f ffff ffff fffe (largest)
  36    * +denorm    0360 0000 0000 0000 8000 0000 0000 0001 (largest)
  37    * -denorm    8360 0000 0000 0000 0000 0000 0000 0001 (largest)
  38    * +denorm    000n nnnn nnnn nnnn xxxx xxxx xxxx xxxx
  39    * -denorm    800n nnnn nnnn nnnn xxxx xxxx xxxx xxxx
  40    */
  41
  42 int
  43 ___fpclassifyl (long double x)
  44 {
  45   uint64_t hx, lx;
  46   int retval = FP_NORMAL;
  47   double xhi, xlo;
  48
  49   ldbl_unpack (x, &xhi, &xlo);
  50   EXTRACT_WORDS64 (hx, xhi);
  51   if ((hx & 0x7ff0000000000000ULL) == 0x7ff0000000000000ULL) {
  52       /* +/-NaN or +/-Inf */
  53       if (hx & 0x000fffffffffffffULL) {
  54           /* +/-NaN */
  55           retval = FP_NAN;
  56       } else {
  57           retval = FP_INFINITE;
  58       }
  59   } else {
  60       /* +/-zero or +/- normal or +/- denormal */
  61       if (hx & 0x7fffffffffffffffULL) {
  62           /* +/- normal or +/- denormal */
  63           if ((hx & 0x7ff0000000000000ULL) > 0x0360000000000000ULL) {
  64               /* +/- normal */
  65               retval = FP_NORMAL;
  66           } else {
  67               if ((hx & 0x7ff0000000000000ULL) == 0x0360000000000000ULL) {
  68                   EXTRACT_WORDS64 (lx, xlo);
  69                   if ((lx & 0x7fffffffffffffff) /* lower is non-zero */
  70                   && ((lx^hx) & 0x8000000000000000ULL)) { /* and sign differs */
  71                       /* +/- denormal */
  72                       retval = FP_SUBNORMAL;
  73                   } else {
  74                       /* +/- normal */
  75                       retval = FP_NORMAL;
  76                   }
  77               } else {
  78                   /* +/- denormal */
  79                   retval = FP_SUBNORMAL;
  80               }
  81           }
  82       } else {
  83           /* +/- zero */
  84           retval = FP_ZERO;
  85       }
  86   }
  87
  88   return retval;
  89 }
  90 long_double_symbol (libm, ___fpclassifyl, __fpclassifyl);
  91 #ifdef __LONG_DOUBLE_MATH_OPTIONAL
  92 libm_hidden_ver (___fpclassifyl, __fpclassifyl)
  93 #else
  94 libm_hidden_def (__fpclassifyl)
  95 #endif