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git.proxmox.com Git - mirror_qemu.git/blob - include/qemu/processor.h
2 * Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
4 * License: GNU GPL, version 2.
5 * See the COPYING file in the top-level directory.
7 #ifndef QEMU_PROCESSOR_H
8 #define QEMU_PROCESSOR_H
10 #if defined(__i386__) || defined(__x86_64__)
11 # define cpu_relax() asm volatile("rep; nop" ::: "memory")
13 #elif defined(__aarch64__)
14 # define cpu_relax() asm volatile("yield" ::: "memory")
16 #elif defined(__powerpc64__)
17 /* set Hardware Multi-Threading (HMT) priority to low; then back to medium */
18 # define cpu_relax() asm volatile("or 1, 1, 1;" \
19 "or 2, 2, 2;" ::: "memory")
22 # define cpu_relax() barrier()
25 #endif /* QEMU_PROCESSOR_H */