cpu_instructions.h

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/*
 * Copyright (c) 2020 Roc Streaming authors
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
//! @file roc_core/target_posix/roc_core/cpu_instructions.h
//! @brief CPU-specific instructions.
 
#ifndef ROC_CORE_CPU_INSTRUCTIONS_H_
#define ROC_CORE_CPU_INSTRUCTIONS_H_
 
namespace roc {
namespace core {
 
#ifdef __GNUC__
 
#if defined(__i386__) || defined(__x86_64__)
 
inline void cpu_relax() {
    __asm__ __volatile__("pause" ::: "memory");
}
 
#elif defined(__aarch64__)
 
inline void cpu_relax() {
    __asm__ __volatile__("yield" ::: "memory");
}
 
#else // unknown arch
 
inline void cpu_relax() {
    __asm__ __volatile__("" ::: "memory");
}
 
#endif
 
#else // !__GNUC__
 
//! CPU pause instruction.
//! @remarks
//!  Doesn't include any memory barriers, so the caller is responsible to
//!  insert them into the loop. Allowed to expand to nothing.
inline void cpu_relax() {
}
 
#endif // __GNUC__
 
} // namespace core
} // namespace roc
 
#endif // ROC_CORE_CPU_INSTRUCTIONS_H_