28 lines
712 B
C
28 lines
712 B
C
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/*
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* Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
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*
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* License: GNU GPL, version 2.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef QEMU_PROCESSOR_H
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#define QEMU_PROCESSOR_H
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#include "qemu/atomic.h"
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#if defined(__i386__) || defined(__x86_64__)
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# define cpu_relax() asm volatile("rep; nop" ::: "memory")
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#elif defined(__aarch64__)
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# define cpu_relax() asm volatile("yield" ::: "memory")
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#elif defined(__powerpc64__)
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/* set Hardware Multi-Threading (HMT) priority to low; then back to medium */
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# define cpu_relax() asm volatile("or 1, 1, 1;" \
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"or 2, 2, 2;" ::: "memory")
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#else
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# define cpu_relax() barrier()
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#endif
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#endif /* QEMU_PROCESSOR_H */
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