| 1 | /* Return the least floating-point number greater than X. |
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| 2 | Copyright (C) 2016-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <float.h> |
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| 20 | #include <math.h> |
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| 21 | #include <math_private.h> |
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| 22 | #include <libm-alias-double.h> |
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| 23 | |
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| 24 | /* Return the least floating-point number greater than X. */ |
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| 25 | double |
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| 26 | __nextup (double x) |
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| 27 | { |
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| 28 | int32_t hx, ix; |
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| 29 | uint32_t lx; |
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| 30 | |
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| 31 | EXTRACT_WORDS (hx, lx, x); |
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| 32 | ix = hx & 0x7fffffff; |
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| 33 | |
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| 34 | if (((ix >= 0x7ff00000) && ((ix - 0x7ff00000) | lx) != 0)) /* x is nan. */ |
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| 35 | return x + x; |
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| 36 | if ((ix | lx) == 0) |
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| 37 | return DBL_TRUE_MIN; |
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| 38 | if (hx >= 0) |
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| 39 | { /* x > 0. */ |
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| 40 | if (isinf (x)) |
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| 41 | return x; |
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| 42 | lx += 1; |
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| 43 | if (lx == 0) |
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| 44 | hx += 1; |
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| 45 | } |
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| 46 | else |
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| 47 | { /* x < 0. */ |
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| 48 | if (lx == 0) |
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| 49 | hx -= 1; |
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| 50 | lx -= 1; |
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| 51 | } |
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| 52 | INSERT_WORDS (x, hx, lx); |
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| 53 | return x; |
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| 54 | } |
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| 55 | |
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| 56 | libm_alias_double (__nextup, nextup) |
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| 57 | |
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