1 /*
 2  * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 #ifndef CPU_AARCH64_SPIN_WAIT_AARCH64_HPP
25 #define CPU_AARCH64_SPIN_WAIT_AARCH64_HPP
26 
27 class SpinWait {
28 public:
29   enum Inst {
30     NONE = -1,
31     NOP,
32     ISB,
33     YIELD,
34     SB
35   };
36 
37 private:
38   Inst _inst;
39   int _count;
40 
41   Inst from_name(const char *name);
42 
43 public:
44   SpinWait(Inst inst = NONE, int count = 0) : _inst(inst), _count(inst == NONE ? 0 : count) {}
45   SpinWait(const char *name, int count) : SpinWait(from_name(name), count) {}
46 
47   Inst inst() const { return _inst; }
48   int inst_count() const { return _count; }
49 
50   static bool supports(const char *name);
51 };
52 
53 #endif // CPU_AARCH64_SPIN_WAIT_AARCH64_HPP