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29 #ifndef __CPU_DECODE_CACHE_HH__
30 #define __CPU_DECODE_CACHE_HH__
32 #include <unordered_map>
34 #include "arch/isa_traits.hh"
35 #include "arch/types.hh"
36 #include "config/the_isa.hh"
37 #include "cpu/static_inst_fwd.hh"
47 /// Hash for decoded instructions.
48 template <typename EMI>
49 using InstMap = std::unordered_map<EMI, StaticInstPtr>;
51 /// A sparse map from an Addr to a Value, stored in page chunks.
56 // A pages worth of cache entries.
58 Value items[TheISA::PageBytes];
60 // A map of cache pages which allows a sparse mapping.
61 typedef typename std::unordered_map<Addr, CachePage *> PageMap;
62 typedef typename PageMap::iterator PageIt;
63 // Mini cache of recent lookups.
67 /// Update the mini cache of recent lookups.
68 /// @param recentest The most recent result;
70 update(PageIt recentest)
72 recent[1] = recent[0];
73 recent[0] = recentest;
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.
83 Addr page_addr = addr & ~(TheISA::PageBytes - 1);
85 // Check against recent lookups.
86 if (recent[0] != pageMap.end()) {
87 if (recent[0]->first == page_addr)
88 return recent[0]->second;
89 if (recent[1] != pageMap.end() &&
90 recent[1]->first == page_addr) {
92 // recent[1] has just become recent[0].
93 return recent[0]->second;
97 // Actually look in the has_map.
98 PageIt it = pageMap.find(page_addr);
99 if (it != pageMap.end()) {
104 // Didn't find an existing page, so add a new one.
105 CachePage *newPage = new CachePage;
106 page_addr = page_addr & ~(TheISA::PageBytes - 1);
107 typename PageMap::value_type to_insert(page_addr, newPage);
108 update(pageMap.insert(to_insert).first);
116 recent[0] = recent[1] = pageMap.end();
122 CachePage *page = getPage(addr);
123 return page->items[addr & (TheISA::PageBytes - 1)];
127 } // namespace DecodeCache
129 #endif // __CPU_DECODE_CACHE_HH__