| /* Round double value to long int. |
| Copyright (C) 1997-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
| |
| 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> |
| #include <libm-alias-double.h> |
| #include <fix-fp-int-convert-overflow.h> |
| |
| |
| long int |
| __lround (double x) |
| { |
| int32_t j0; |
| uint32_t i1, i0; |
| long int result; |
| int sign; |
| |
| EXTRACT_WORDS (i0, i1, x); |
| j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; |
| sign = (i0 & 0x80000000) != 0 ? -1 : 1; |
| i0 &= 0xfffff; |
| i0 |= 0x100000; |
| |
| if (j0 < 20) |
| { |
| if (j0 < 0) |
| return j0 < -1 ? 0 : sign; |
| else |
| { |
| i0 += 0x80000 >> j0; |
| |
| result = i0 >> (20 - j0); |
| } |
| } |
| else if (j0 < (int32_t) (8 * sizeof (long int)) - 1) |
| { |
| if (j0 >= 52) |
| result = ((long int) i0 << (j0 - 20)) | ((long int) i1 << (j0 - 52)); |
| else |
| { |
| uint32_t j = i1 + (0x80000000 >> (j0 - 20)); |
| if (j < i1) |
| ++i0; |
| |
| if (j0 == 20) |
| result = (long int) i0; |
| else |
| { |
| result = ((long int) i0 << (j0 - 20)) | (j >> (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 (FIX_DBL_LONG_CONVERT_OVERFLOW |
| && !(sign == -1 |
| && (sizeof (long int) == 4 |
| ? x > (double) LONG_MIN - 0.5 |
| : x >= (double) LONG_MIN))) |
| { |
| feraiseexcept (FE_INVALID); |
| return sign == 1 ? LONG_MAX : LONG_MIN; |
| } |
| else if (!FIX_DBL_LONG_CONVERT_OVERFLOW |
| && 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; |
| } |
| |
| libm_alias_double (__lround, lround) |
