diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c')
-rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c | 90 |
1 files changed, 89 insertions, 1 deletions
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c index 1e06fcb16e..9e665b01ec 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c @@ -1 +1,89 @@ -/* The code is the same as llround. Use an alias, see s_llround.c. */ +/* Round double value to long int. + 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 <fenv.h> +#include <limits.h> +#include <math.h> + +#include <math_private.h> + +/* For LP64, lround is an alias for llround. */ +#ifndef _LP64 + +long int +__lround (double x) +{ + int32_t j0; + int64_t i0; + long int result; + int sign; + + EXTRACT_WORDS64 (i0, x); + j0 = ((i0 >> 52) & 0x7ff) - 0x3ff; + sign = i0 < 0 ? -1 : 1; + i0 &= UINT64_C(0xfffffffffffff); + i0 |= UINT64_C(0x10000000000000); + + if (j0 < (int32_t) (8 * sizeof (long int)) - 1) + { + if (j0 < 0) + return j0 < -1 ? 0 : sign; + else if (j0 >= 52) + result = i0 << (j0 - 52); + else + { + i0 += UINT64_C(0x8000000000000) >> j0; + + result = i0 >> (52 - j0); +#ifdef FE_INVALID + if (sizeof (long int) == 4 + && sign == 1 + && result == LONG_MIN) + /* Rounding brought the value out of range. */ + feraiseexcept (FE_INVALID); +#endif + } + } + else + { + /* The number is too large. Unless it rounds to LONG_MIN, + FE_INVALID must be raised and the return value is + unspecified. */ +#ifdef FE_INVALID + if (sizeof (long int) == 4 + && x <= (double) LONG_MIN - 0.5) + { + /* If truncation produces LONG_MIN, the cast will not raise + the exception, but may raise "inexact". */ + feraiseexcept (FE_INVALID); + return LONG_MIN; + } +#endif + return (long int) x; + } + + return sign * result; +} + +weak_alias (__lround, lround) +# ifdef NO_LONG_DOUBLE +strong_alias (__lround, __lroundl) +weak_alias (__lround, lroundl) +# endif + +#endif |