diff options
Diffstat (limited to 'sysdeps/i386/fpu')
| -rw-r--r-- | sysdeps/i386/fpu/s_fdim.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/s_fdim.c b/sysdeps/i386/fpu/s_fdim.c new file mode 100644 index 0000000000..e4db9bf66c --- /dev/null +++ b/sysdeps/i386/fpu/s_fdim.c @@ -0,0 +1,50 @@ +/* Return positive difference between arguments. i386 version. + Copyright (C) 1997-2016 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> + +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; +} +weak_alias (__fdim, fdim) +#ifdef NO_LONG_DOUBLE +strong_alias (__fdim, __fdiml) +weak_alias (__fdim, fdiml) +#endif |