1 /* Round double value to long long int. 2 Copyright (C) 1997 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. 5 6 The GNU C Library is free software; you can redistribute it and/or 7 modify it under the terms of the GNU Lesser General Public 8 License as published by the Free Software Foundation; either 9 version 2.1 of the License, or (at your option) any later version. 10 11 The GNU C Library is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 Lesser General Public License for more details. 15 16 You should have received a copy of the GNU Lesser General Public 17 License along with the GNU C Library; if not, see 18 <http://www.gnu.org/licenses/>. */ 19 20 #include <math.h> 21 #include "math_private.h" 22 23 long long int llround(double x)24llround (double x) 25 { 26 int32_t _j0; 27 u_int32_t i1, i0; 28 long long int result; 29 int sign; 30 31 EXTRACT_WORDS (i0, i1, x); 32 _j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; 33 sign = (i0 & 0x80000000) != 0 ? -1 : 1; 34 i0 &= 0xfffff; 35 i0 |= 0x100000; 36 37 if (_j0 < 20) 38 { 39 if (_j0 < 0) 40 return _j0 < -1 ? 0 : sign; 41 else 42 { 43 i0 += 0x80000 >> _j0; 44 45 result = i0 >> (20 - _j0); 46 } 47 } 48 else if (_j0 < (int32_t) (8 * sizeof (long long int)) - 1) 49 { 50 if (_j0 >= 52) 51 result = (((long long int) i0 << 32) | i1) << (_j0 - 52); 52 else 53 { 54 u_int32_t j = i1 + (0x80000000 >> (_j0 - 20)); 55 if (j < i1) 56 ++i0; 57 58 if (_j0 == 20) 59 result = (long long int) i0; 60 else 61 result = ((long long int) i0 << (_j0 - 20)) | (j >> (52 - _j0)); 62 } 63 } 64 else 65 { 66 /* The number is too large. It is left implementation defined 67 what happens. */ 68 return (long long int) x; 69 } 70 71 return sign * result; 72 } 73 libm_hidden_def(llround) 74