sysdeps/ieee754/dbl-64/s_totalorder.c

   1 /* Total order operation.  dbl-64 version.
   2    Copyright (C) 2016-2021 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 #include <math_private.h>
  21 #include <libm-alias-double.h>
  22 #include <nan-high-order-bit.h>
  23 #include <stdint.h>
  24 #include <shlib-compat.h>
  25 #include <first-versions.h>
  26
  27 int
  28 __totalorder (const double *x, const double *y)
  29 {
  30   int32_t hx, hy;
  31   uint32_t lx, ly;
  32   EXTRACT_WORDS (hx, lx, *x);
  33   EXTRACT_WORDS (hy, ly, *y);
  34 #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
  35   uint32_t uhx = hx & 0x7fffffff, uhy = hy & 0x7fffffff;
  36   /* For the preferred quiet NaN convention, this operation is a
  37      comparison of the representations of the arguments interpreted as
  38      sign-magnitude integers.  If both arguments are NaNs, invert the
  39      quiet/signaling bit so comparing that way works.  */
  40   if ((uhx > 0x7ff00000 || (uhx == 0x7ff00000 && lx != 0))
  41       && (uhy > 0x7ff00000 || (uhy == 0x7ff00000 && ly != 0)))
  42     {
  43       hx ^= 0x00080000;
  44       hy ^= 0x00080000;
  45     }
  46 #endif
  47   uint32_t hx_sign = hx >> 31;
  48   uint32_t hy_sign = hy >> 31;
  49   hx ^= hx_sign >> 1;
  50   lx ^= hx_sign;
  51   hy ^= hy_sign >> 1;
  52   ly ^= hy_sign;
  53   return hx < hy || (hx == hy && lx <= ly);
  54 }
  55 #ifdef SHARED
  56 # define CONCATX(x, y) x ## y
  57 # define CONCAT(x, y) CONCATX (x, y)
  58 # define UNIQUE_ALIAS(name) CONCAT (name, __COUNTER__)
  59 # define do_symbol(orig_name, name, aliasname)          \
  60   strong_alias (orig_name, name)                        \
  61   versioned_symbol (libm, name, aliasname, GLIBC_2_31)
  62 # undef weak_alias
  63 # define weak_alias(name, aliasname)                    \
  64   do_symbol (name, UNIQUE_ALIAS (name), aliasname);
  65 #endif
  66 libm_alias_double (__totalorder, totalorder)
  67 #if SHLIB_COMPAT (libm, GLIBC_2_25, GLIBC_2_31)
  68 int
  69 attribute_compat_text_section
  70 __totalorder_compat (double x, double y)
  71 {
  72   return __totalorder (&x, &y);
  73 }
  74 #undef do_symbol
  75 #define do_symbol(orig_name, name, aliasname)                   \
  76   strong_alias (orig_name, name)                                \
  77   compat_symbol (libm, name, aliasname,                         \
  78                  CONCAT (FIRST_VERSION_libm_, aliasname))
  79 libm_alias_double (__totalorder_compat, totalorder)
  80 #endif