sysdeps/ieee754/soft-fp/s_dsubl.c

   1 /* Subtract long double (ldbl-128) values, narrowing the result to
   2    double, using soft-fp.
   3    Copyright (C) 2018-2019 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #define f32xsubf64x __hide_f32xsubf64x
  21 #define f32xsubf128 __hide_f32xsubf128
  22 #define f64subf64x __hide_f64subf64x
  23 #define f64subf128 __hide_f64subf128
  24 #include <math.h>
  25 #undef f32xsubf64x
  26 #undef f32xsubf128
  27 #undef f64subf64x
  28 #undef f64subf128
  29
  30 #include <math-narrow.h>
  31 #include <soft-fp.h>
  32 #include <double.h>
  33 #include <quad.h>
  34
  35 double
  36 __dsubl (_Float128 x, _Float128 y)
  37 {
  38   FP_DECL_EX;
  39   FP_DECL_Q (X);
  40   FP_DECL_Q (Y);
  41   FP_DECL_Q (R);
  42   FP_DECL_D (RN);
  43   double ret;
  44
  45   FP_INIT_ROUNDMODE;
  46   FP_UNPACK_SEMIRAW_Q (X, x);
  47   FP_UNPACK_SEMIRAW_Q (Y, y);
  48   FP_SUB_Q (R, X, Y);
  49 #if _FP_W_TYPE_SIZE < 64
  50   FP_TRUNC (D, Q, 2, 4, RN, R);
  51 #else
  52   FP_TRUNC (D, Q, 1, 2, RN, R);
  53 #endif
  54   FP_PACK_SEMIRAW_D (ret, RN);
  55   FP_HANDLE_EXCEPTIONS;
  56   CHECK_NARROW_SUB (ret, x, y);
  57   return ret;
  58 }
  59 libm_alias_double_ldouble (sub)