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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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.hh"
39
40namespace TheISA
41{
42 class Decoder;
43}
44
45class DecodeCache
46{
47 private:
48 typedef TheISA::ExtMachInst ExtMachInst;
49
50 /// Hash of decoded instructions.
51 typedef m5::hash_map<ExtMachInst, StaticInstPtr> InstMap;
52 InstMap instMap;
53 struct DecodePage {
54 StaticInstPtr insts[TheISA::PageBytes];
55 };
56
57 /// A store of DecodePages. Basically a slightly smarter hash_map.
58 class DecodePages
59 {
60 protected:
61 typedef typename m5::hash_map<Addr, DecodePage *> PageMap;
62 typedef typename PageMap::iterator PageIt;
63 PageIt recent[2];
64 PageMap pageMap;
65
66 /// Update the small cache of recent lookups.
67 /// @param recentest The most recent result;
68 void update(PageIt recentest);
69 void addPage(Addr addr, DecodePage *page);
70
71 public:
72 /// Constructor
73 DecodePages();
74
75 /// Attempt to find the DecodePage which goes with a particular
76 /// address. First check the small cache of recent results, then
77 /// actually look in the hash_map.
78 /// @param addr The address to look up.
79 DecodePage *getPage(Addr addr);
80 } decodePages;
81
82 public:
83 /// Decode a machine instruction.
84 /// @param mach_inst The binary instruction to decode.
85 /// @retval A pointer to the corresponding StaticInst object.
86 StaticInstPtr decode(TheISA::Decoder * const decoder,
87 ExtMachInst mach_inst, Addr addr);
88};
89
90#endif // __CPU_DECODE_CACHE_HH__