1 /*
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 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 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).
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24 
25 #ifndef SHARE_RUNTIME_PREFETCH_HPP
26 #define SHARE_RUNTIME_PREFETCH_HPP
27 
28 #include "memory/allocation.hpp"
29 
30 // If calls to prefetch methods are in a loop, the loop should be cloned
31 // such that if Prefetch{Scan,Copy}Interval and/or PrefetchFieldInterval
32 // say not to do prefetching, these methods aren't called.  At the very
33 // least, they take up a memory issue slot.  They should be implemented
34 // as inline assembly code: doing an actual call isn't worth the cost.
35 
36 class Prefetch : AllStatic {
37  public:
38   enum style {
39     do_none,  // Do no prefetching
40     do_read,  // Do read prefetching
41     do_write  // Do write prefetching
42   };
43 
44   // Prefetch anticipating read; must not fault, semantically a no-op
45   static void read(void* loc, intx interval);
46   static void read_streaming(void* loc, intx interval);
47 
48   // Prefetch anticipating write; must not fault, semantically a no-op
49   static void write(void* loc, intx interval);
50 };
51 
52 #endif // SHARE_RUNTIME_PREFETCH_HPP