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- /* Copyright (C) 2012-2022 Free Software Foundation, Inc.
- Contributed by Richard Henderson <rth@redhat.com>.
- This file is part of the GNU Atomic Library (libatomic).
- Libatomic is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- Libatomic 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 General Public License for
- more details.
- Under Section 7 of GPL version 3, you are granted additional
- permissions described in the GCC Runtime Library Exception, version
- 3.1, as published by the Free Software Foundation.
- You should have received a copy of the GNU General Public License and
- a copy of the GCC Runtime Library Exception along with this program;
- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- <http://www.gnu.org/licenses/>. */
- #include "libatomic_i.h"
- #if HAVE_IFUNC
- unsigned int __libat_feat1;
- unsigned int
- __libat_feat1_init (void)
- {
- unsigned int eax, ebx, ecx, edx;
- FEAT1_REGISTER = 0;
- __get_cpuid (1, &eax, &ebx, &ecx, &edx);
- #ifdef __x86_64__
- if ((FEAT1_REGISTER & (bit_AVX | bit_CMPXCHG16B))
- == (bit_AVX | bit_CMPXCHG16B))
- {
- /* Intel SDM guarantees that 16-byte VMOVDQA on 16-byte aligned address
- is atomic, but so far we don't have this guarantee from AMD. */
- unsigned int ecx2 = 0;
- __get_cpuid (0, &eax, &ebx, &ecx2, &edx);
- if (ecx2 != signature_INTEL_ecx)
- FEAT1_REGISTER &= ~bit_AVX;
- }
- #endif
- /* See the load in load_feat1. */
- __atomic_store_n (&__libat_feat1, FEAT1_REGISTER, __ATOMIC_RELAXED);
- return FEAT1_REGISTER;
- }
- #endif /* HAVE_IFUNC */
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