sysdeps/ieee754/soft-fp/s_fsub.c

   1 /* Subtract double values, narrowing the result to float, using soft-fp.
   2    Copyright (C) 2018 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #define f32subf64 __hide_f32subf64
  20 #define f32subf32x __hide_f32subf32x
  21 #define fsubl __hide_fsubl
  22 #include <math.h>
  23 #undef f32subf64
  24 #undef f32subf32x
  25 #undef fsubl
  26
  27 #include <math-narrow.h>
  28 #include <soft-fp.h>
  29 #include <single.h>
  30 #include <double.h>
  31
  32 float
  33 __fsub (double x, double y)
  34 {
  35   FP_DECL_EX;
  36   FP_DECL_D (X);
  37   FP_DECL_D (Y);
  38   FP_DECL_D (R);
  39   FP_DECL_S (RN);
  40   float ret;
  41
  42   FP_INIT_ROUNDMODE;
  43   FP_UNPACK_SEMIRAW_D (X, x);
  44   FP_UNPACK_SEMIRAW_D (Y, y);
  45   FP_SUB_D (R, X, Y);
  46 #if _FP_W_TYPE_SIZE < _FP_FRACBITS_D
  47   FP_TRUNC (S, D, 1, 2, RN, R);
  48 #else
  49   FP_TRUNC (S, D, 1, 1, RN, R);
  50 #endif
  51   FP_PACK_SEMIRAW_S (ret, RN);
  52   FP_HANDLE_EXCEPTIONS;
  53   CHECK_NARROW_SUB (ret, x, y);
  54   return ret;
  55 }
  56 libm_alias_float_double (sub)