1/*
2 * Copyright (c) 2011 Google
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;

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26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Gabe Black
29 */
30
31#ifndef __CPU_DECODE_CACHE_HH__
32#define __CPU_DECODE_CACHE_HH__
33
34#include "arch/isa_traits.hh"
35#include "arch/types.hh"
36#include "base/hashmap.hh"
37#include "config/the_isa.hh"
38#include "cpu/static_inst_fwd.hh"
39
40namespace TheISA
41{
42 class Decoder;
43}
44
45namespace DecodeCache
46{
47
48/// Hash for decoded instructions.
49typedef m5::hash_map<TheISA::ExtMachInst, StaticInstPtr> InstMap;
50
51/// A sparse map from an Addr to a Value, stored in page chunks.
52template<class Value>
53class AddrMap
54{
55 protected:
56 // A pages worth of cache entries.
57 struct CachePage {
58 Value items[TheISA::PageBytes];
59 };
60 // A map of cache pages which allows a sparse mapping.
61 typedef typename m5::hash_map<Addr, CachePage *> PageMap;
62 typedef typename PageMap::iterator PageIt;
63 // Mini cache of recent lookups.
64 PageIt recent[2];
65 PageMap pageMap;
66
67 /// Update the mini cache of recent lookups.
68 /// @param recentest The most recent result;
69 void
70 update(PageIt recentest)
71 {
72 recent[1] = recent[0];
73 recent[0] = recentest;
74 }
75
76 /// Attempt to find the CacheePage which goes with a particular
77 /// address. First check the small cache of recent results, then
78 /// actually look in the hash_map.
79 /// @param addr The address to look up.
80 CachePage *
81 getPage(Addr addr)
82 {
83 Addr page_addr = addr & ~(TheISA::PageBytes - 1);
84
85 // Check against recent lookups.
86 if (recent[0] != pageMap.end()) {

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