| 1 | /* Round float value to long long int. |
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| 2 | Copyright (C) 1997-2024 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 <math.h> |
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| 20 | #include <math_private.h> |
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| 21 | #include <stdint.h> |
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| 22 | #include <libm-alias-float.h> |
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| 23 | |
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| 24 | /* Round to the nearest integer, with values exactly on a 0.5 boundary |
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| 25 | rounded away from zero, regardless of the current rounding mode. |
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| 26 | If (long long)x, when x is out of range of a long long, clips at |
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| 27 | LLONG_MAX or LLONG_MIN, then this implementation also clips. */ |
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| 28 | |
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| 29 | long long int |
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| 30 | __llroundf (float x) |
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| 31 | { |
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| 32 | long long xr; |
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| 33 | if (HAVE_PPC_FCTIDZ) |
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| 34 | xr = (long long) x; |
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| 35 | else |
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| 36 | { |
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| 37 | float ax = fabsf (x: x); |
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| 38 | /* Avoid incorrect exceptions from libgcc conversions (as of GCC |
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| 39 | 5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>. */ |
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| 40 | if (ax < 0x1p31f) |
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| 41 | xr = (long long int) (long int) x; |
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| 42 | else if (!(ax < 0x1p55f)) |
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| 43 | xr = (long long int) (long int) (x * 0x1p-32f) << 32; |
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| 44 | else |
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| 45 | { |
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| 46 | uint32_t i0; |
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| 47 | GET_FLOAT_WORD (i0, x); |
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| 48 | int exponent = ((i0 >> 23) & 0xff) - 0x7f; |
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| 49 | unsigned long long int mant = (i0 & 0x7fffff) | 0x800000; |
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| 50 | mant <<= exponent - 23; |
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| 51 | xr = (long long int) ((i0 & 0x80000000) != 0 ? -mant : mant); |
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| 52 | } |
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| 53 | } |
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| 54 | /* Avoid spurious "inexact" converting LLONG_MAX to float, and from |
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| 55 | subtraction when the result is out of range, by returning early |
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| 56 | for arguments large enough that no rounding is needed. */ |
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| 57 | if (!(fabsf (x: x) < 0x1p23f)) |
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| 58 | return xr; |
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| 59 | float xrf = (float) xr; |
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| 60 | |
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| 61 | if (x >= 0.0) |
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| 62 | { |
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| 63 | if (x - xrf >= 0.5) |
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| 64 | xr += (long long) ((unsigned long long) xr + 1) > 0; |
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| 65 | } |
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| 66 | else |
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| 67 | { |
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| 68 | if (xrf - x >= 0.5) |
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| 69 | xr -= (long long) ((unsigned long long) xr - 1) < 0; |
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| 70 | } |
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| 71 | return xr; |
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| 72 | } |
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| 73 | libm_alias_float (__llround, llround) |
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| 74 | |
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