1 /* Round long double value to long int. 2 Copyright (C) 1997-2018 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and 5 Jakub Jelinek <jj@ultra.linux.cz>, 1999. 6 7 The GNU C Library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU Lesser General Public 9 License as published by the Free Software Foundation; either 10 version 2.1 of the License, or (at your option) any later version. 11 12 The GNU C Library is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 Lesser General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public 18 License along with the GNU C Library; if not, see 19 <http://www.gnu.org/licenses/>. */ 20 21 #include "quadmath-imp.h" 22 23 long int 24 lroundq (__float128 x) 25 { 26 int64_t j0; 27 uint64_t i1, i0; 28 long int result; 29 int sign; 30 31 GET_FLT128_WORDS64 (i0, i1, x); 32 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff; 33 sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1; 34 i0 &= 0x0000ffffffffffffLL; 35 i0 |= 0x0001000000000000LL; 36 37 if (j0 < (int32_t) (8 * sizeof (long int)) - 1) 38 { 39 if (j0 < 48) 40 { 41 if (j0 < 0) 42 return j0 < -1 ? 0 : sign; 43 else 44 { 45 i0 += 0x0000800000000000LL >> j0; 46 result = i0 >> (48 - j0); 47 #ifdef FE_INVALID 48 if (sizeof (long int) == 4 49 && sign == 1 50 && result == LONG_MIN) 51 /* Rounding brought the value out of range. */ 52 feraiseexcept (FE_INVALID); 53 #endif 54 } 55 } 56 else if (j0 >= 112) 57 result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112)); 58 else 59 { 60 uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48)); 61 if (j < i1) 62 ++i0; 63 64 if (j0 == 48) 65 result = (long int) i0; 66 else 67 { 68 result = ((long int) i0 << (j0 - 48)) | (j >> (112 - j0)); 69 #ifdef FE_INVALID 70 if (sizeof (long int) == 8 71 && sign == 1 72 && result == LONG_MIN) 73 /* Rounding brought the value out of range. */ 74 feraiseexcept (FE_INVALID); 75 #endif 76 } 77 } 78 } 79 else 80 { 81 /* The number is too large. Unless it rounds to LONG_MIN, 82 FE_INVALID must be raised and the return value is 83 unspecified. */ 84 #ifdef FE_INVALID 85 if (FIX_FLT128_LONG_CONVERT_OVERFLOW 86 && !(sign == -1 && x > (__float128) LONG_MIN - 0.5Q)) 87 { 88 feraiseexcept (FE_INVALID); 89 return sign == 1 ? LONG_MAX : LONG_MIN; 90 } 91 else if (!FIX_FLT128_LONG_CONVERT_OVERFLOW 92 && x <= (__float128) LONG_MIN - 0.5Q) 93 { 94 /* If truncation produces LONG_MIN, the cast will not raise 95 the exception, but may raise "inexact". */ 96 feraiseexcept (FE_INVALID); 97 return LONG_MIN; 98 } 99 #endif 100 /* The number is too large. It is left implementation defined 101 what happens. */ 102 return (long int) x; 103 } 104 105 return sign * result; 106 } 107