| 1 | /* Copyright (C) 2011-2022 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | #include <errno.h> |
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| 19 | #include <math.h> |
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| 20 | #include <math_private.h> |
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| 21 | #include <math-svid-compat.h> |
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| 22 | |
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| 23 | |
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| 24 | #if LIBM_SVID_COMPAT |
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| 25 | static double |
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| 26 | __attribute__ ((noinline)) |
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| 27 | sysv_scalb (double x, double fn) |
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| 28 | { |
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| 29 | double z = __ieee754_scalb (x, fn); |
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| 30 | |
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| 31 | if (__glibc_unlikely (isinf (z))) |
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| 32 | { |
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| 33 | if (isfinite (x)) |
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| 34 | return __kernel_standard (x, fn, 32); /* scalb overflow */ |
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| 35 | else |
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| 36 | __set_errno (ERANGE); |
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| 37 | } |
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| 38 | else if (__builtin_expect (z == 0.0, 0) && z != x) |
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| 39 | return __kernel_standard (x, fn, 33); /* scalb underflow */ |
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| 40 | |
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| 41 | return z; |
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| 42 | } |
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| 43 | |
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| 44 | |
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| 45 | /* Wrapper scalb */ |
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| 46 | double |
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| 47 | __scalb (double x, double fn) |
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| 48 | { |
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| 49 | if (__glibc_unlikely (_LIB_VERSION == _SVID_)) |
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| 50 | return sysv_scalb (x, fn); |
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| 51 | else |
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| 52 | { |
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| 53 | double z = __ieee754_scalb (x, fn); |
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| 54 | |
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| 55 | if (__glibc_unlikely (!isfinite (z) || z == 0.0)) |
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| 56 | { |
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| 57 | if (isnan (z)) |
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| 58 | { |
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| 59 | if (!isnan (x) && !isnan (fn)) |
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| 60 | __set_errno (EDOM); |
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| 61 | } |
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| 62 | else if (isinf (z)) |
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| 63 | { |
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| 64 | if (!isinf (x) && !isinf (fn)) |
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| 65 | __set_errno (ERANGE); |
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| 66 | } |
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| 67 | else |
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| 68 | { |
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| 69 | /* z == 0. */ |
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| 70 | if (x != 0.0 && !isinf (fn)) |
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| 71 | __set_errno (ERANGE); |
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| 72 | } |
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| 73 | } |
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| 74 | return z; |
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| 75 | } |
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| 76 | } |
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| 77 | weak_alias (__scalb, scalb) |
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| 78 | # ifdef NO_LONG_DOUBLE |
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| 79 | strong_alias (__scalb, __scalbl) |
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| 80 | weak_alias (__scalb, scalbl) |
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| 81 | # endif |
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| 82 | #endif |
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| 83 | |
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