| /* Round to int long double floating-point values. |
| IBM extended format long double version. |
| Copyright (C) 2006-2014 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/>. */ |
| |
| /* This has been coded in assembler because GCC makes such a mess of it |
| when it's coded in C. */ |
| |
| #include <math.h> |
| #include <fenv_libc.h> |
| #include <math_ldbl_opt.h> |
| #include <float.h> |
| #include <ieee754.h> |
| |
| |
| long double |
| __rintl (long double x) |
| { |
| double xh, xl, hi, lo; |
| |
| ldbl_unpack (x, &xh, &xl); |
| |
| /* Return Inf, Nan, +/-0 unchanged. */ |
| if (__builtin_expect (xh != 0.0 |
| && __builtin_isless (__builtin_fabs (xh), |
| __builtin_inf ()), 1)) |
| { |
| double orig_xh; |
| int save_round = __fegetround (); |
| |
| /* Long double arithmetic, including the canonicalisation below, |
| only works in round-to-nearest mode. */ |
| fesetround (FE_TONEAREST); |
| |
| /* Convert the high double to integer. */ |
| orig_xh = xh; |
| hi = ldbl_nearbyint (xh); |
| |
| /* Subtract integral high part from the value. If the low double |
| happens to be exactly 0.5 or -0.5, you might think that this |
| subtraction could result in an incorrect conversion. For |
| instance, subtracting an odd number would cause this function |
| to round in the wrong direction. However, if we have a |
| canonical long double with the low double 0.5 or -0.5, then the |
| high double must be even. */ |
| xh -= hi; |
| ldbl_canonicalize (&xh, &xl); |
| |
| /* Now convert the low double, adjusted for any remainder from the |
| high double. */ |
| lo = ldbl_nearbyint (xh); |
| |
| xh -= lo; |
| ldbl_canonicalize (&xh, &xl); |
| |
| switch (save_round) |
| { |
| case FE_TONEAREST: |
| if (xl > 0.0 && xh == 0.5) |
| lo += 1.0; |
| else if (xl < 0.0 && -xh == 0.5) |
| lo -= 1.0; |
| break; |
| |
| case FE_TOWARDZERO: |
| if (orig_xh < 0.0) |
| goto do_up; |
| /* Fall thru */ |
| |
| case FE_DOWNWARD: |
| if (xh < 0.0 || (xh == 0.0 && xl < 0.0)) |
| lo -= 1.0; |
| break; |
| |
| case FE_UPWARD: |
| do_up: |
| if (xh > 0.0 || (xh == 0.0 && xl > 0.0)) |
| lo += 1.0; |
| break; |
| } |
| |
| /* Ensure the final value is canonical. In certain cases, |
| rounding causes hi,lo calculated so far to be non-canonical. */ |
| xh = hi; |
| xl = lo; |
| ldbl_canonicalize (&xh, &xl); |
| |
| /* Ensure we return -0 rather than +0 when appropriate. */ |
| if (orig_xh < 0.0) |
| xh = -__builtin_fabs (xh); |
| |
| fesetround (save_round); |
| } |
| |
| return ldbl_pack (xh, xl); |
| } |
| |
| long_double_symbol (libm, __rintl, rintl); |