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 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 /* Round double to integer away from zero. Copyright (C) 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper , 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include #include "math_private.h" static const double huge = 1.0e300; double round (double x) { int32_t i0, j0; u_int32_t i1; EXTRACT_WORDS (i0, i1, x); j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; if (j0 < 20) { if (j0 < 0) { if (huge + x > 0.0) { i0 &= 0x80000000; if (j0 == -1) i0 |= 0x3ff00000; i1 = 0; } } else { u_int32_t i = 0x000fffff >> j0; if (((i0 & i) | i1) == 0) /* X is integral. */ return x; if (huge + x > 0.0) { /* Raise inexact if x != 0. */ i0 += 0x00080000 >> j0; i0 &= ~i; i1 = 0; } } } else if (j0 > 51) { if (j0 == 0x400) /* Inf or NaN. */ return x + x; else return x; } else { u_int32_t i = 0xffffffff >> (j0 - 20); if ((i1 & i) == 0) /* X is integral. */ return x; if (huge + x > 0.0) { /* Raise inexact if x != 0. */ u_int32_t j = i1 + (1 << (51 - j0)); if (j < i1) i0 += 1; i1 = j; } i1 &= ~i; } INSERT_WORDS (x, i0, i1); return x; } libm_hidden_def(round)