| 1 | /* Set current rounding direction. |
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| 2 | Copyright (C) 1997-2022 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 <fenv.h> |
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| 20 | #include <unistd.h> |
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| 21 | #include <ldsodefs.h> |
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| 22 | #include <dl-procinfo.h> |
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| 23 | |
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| 24 | int |
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| 25 | __fesetround (int round) |
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| 26 | { |
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| 27 | unsigned short int cw; |
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| 28 | |
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| 29 | if ((round & ~0xc00) != 0) |
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| 30 | /* ROUND is no valid rounding mode. */ |
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| 31 | return 1; |
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| 32 | |
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| 33 | __asm__ ("fnstcw %0" : "=m" (*&cw)); |
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| 34 | cw &= ~0xc00; |
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| 35 | cw |= round; |
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| 36 | __asm__ ("fldcw %0" : : "m" (*&cw)); |
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| 37 | |
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| 38 | /* If the CPU supports SSE we set the MXCSR as well. */ |
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| 39 | if (CPU_FEATURE_USABLE (SSE)) |
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| 40 | { |
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| 41 | unsigned int xcw; |
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| 42 | |
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| 43 | __asm__ ("stmxcsr %0" : "=m" (*&xcw)); |
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| 44 | xcw &= ~0x6000; |
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| 45 | xcw |= round << 3; |
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| 46 | __asm__ ("ldmxcsr %0" : : "m" (*&xcw)); |
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| 47 | } |
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| 48 | |
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| 49 | return 0; |
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| 50 | } |
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| 51 | libm_hidden_def (__fesetround) |
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| 52 | weak_alias (__fesetround, fesetround) |
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| 53 | libm_hidden_weak (fesetround) |
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| 54 | |
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