| /* Return positive difference between arguments. i386 version. |
| Copyright (C) 1997-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <fpu_control.h> |
| #include <math.h> |
| #include <math_private.h> |
| #include <libm-alias-double.h> |
| |
| double |
| __fdim (double x, double y) |
| { |
| if (islessequal (x, y)) |
| return 0.0; |
| |
| /* To avoid double rounding, set double precision for the |
| subtraction. math_narrow_eval is still needed to eliminate |
| excess range in the case of overflow. If the result of the |
| subtraction is in the subnormal range for double, it is exact, so |
| no issues of double rounding for subnormals arise. */ |
| fpu_control_t cw, cw_double; |
| _FPU_GETCW (cw); |
| cw_double = (cw & ~_FPU_EXTENDED) | _FPU_DOUBLE; |
| _FPU_SETCW (cw_double); |
| double r = math_narrow_eval (x - y); |
| _FPU_SETCW (cw); |
| if (isinf (r) && !isinf (x) && !isinf (y)) |
| __set_errno (ERANGE); |
| |
| return r; |
| } |
| libm_alias_double (__fdim, fdim) |
