store_set.hh (2670:9107b8bd08cd) store_set.hh (2674:6d4afef73a20)
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
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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41
42struct ltseqnum {
43 bool operator()(const InstSeqNum &lhs, const InstSeqNum &rhs) const
44 {
45 return lhs > rhs;
46 }
47};
48
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
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;

--- 32 unchanged lines hidden (view full) ---

41
42struct ltseqnum {
43 bool operator()(const InstSeqNum &lhs, const InstSeqNum &rhs) const
44 {
45 return lhs > rhs;
46 }
47};
48
49/**
50 * Implements a store set predictor for determining if memory
51 * instructions are dependent upon each other. See paper "Memory
52 * Dependence Prediction using Store Sets" by Chrysos and Emer. SSID
53 * stands for Store Set ID, SSIT stands for Store Set ID Table, and
54 * LFST is Last Fetched Store Table.
55 */
49class StoreSet
50{
51 public:
52 typedef unsigned SSID;
53
54 public:
56class StoreSet
57{
58 public:
59 typedef unsigned SSID;
60
61 public:
62 /** Default constructor. init() must be called prior to use. */
55 StoreSet() { };
56
63 StoreSet() { };
64
65 /** Creates store set predictor with given table sizes. */
57 StoreSet(int SSIT_size, int LFST_size);
58
66 StoreSet(int SSIT_size, int LFST_size);
67
68 /** Default destructor. */
59 ~StoreSet();
60
69 ~StoreSet();
70
71 /** Initializes the store set predictor with the given table sizes. */
61 void init(int SSIT_size, int LFST_size);
62
72 void init(int SSIT_size, int LFST_size);
73
74 /** Records a memory ordering violation between the younger load
75 * and the older store. */
63 void violation(Addr store_PC, Addr load_PC);
64
76 void violation(Addr store_PC, Addr load_PC);
77
78 /** Inserts a load into the store set predictor. This does nothing but
79 * is included in case other predictors require a similar function.
80 */
65 void insertLoad(Addr load_PC, InstSeqNum load_seq_num);
66
81 void insertLoad(Addr load_PC, InstSeqNum load_seq_num);
82
83 /** Inserts a store into the store set predictor. Updates the
84 * LFST if the store has a valid SSID. */
67 void insertStore(Addr store_PC, InstSeqNum store_seq_num,
68 unsigned tid);
69
85 void insertStore(Addr store_PC, InstSeqNum store_seq_num,
86 unsigned tid);
87
88 /** Checks if the instruction with the given PC is dependent upon
89 * any store. @return Returns the sequence number of the store
90 * instruction this PC is dependent upon. Returns 0 if none.
91 */
70 InstSeqNum checkInst(Addr PC);
71
92 InstSeqNum checkInst(Addr PC);
93
94 /** Records this PC/sequence number as issued. */
72 void issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store);
73
95 void issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store);
96
97 /** Squashes for a specific thread until the given sequence number. */
74 void squash(InstSeqNum squashed_num, unsigned tid);
75
98 void squash(InstSeqNum squashed_num, unsigned tid);
99
100 /** Resets all tables. */
76 void clear();
77
101 void clear();
102
103 /** Debug function to dump the contents of the store list. */
104 void dump();
105
78 private:
106 private:
107 /** Calculates the index into the SSIT based on the PC. */
79 inline int calcIndex(Addr PC)
80 { return (PC >> offsetBits) & indexMask; }
81
108 inline int calcIndex(Addr PC)
109 { return (PC >> offsetBits) & indexMask; }
110
111 /** Calculates a Store Set ID based on the PC. */
82 inline SSID calcSSID(Addr PC)
83 { return ((PC ^ (PC >> 10)) % LFSTSize); }
84
112 inline SSID calcSSID(Addr PC)
113 { return ((PC ^ (PC >> 10)) % LFSTSize); }
114
115 /** The Store Set ID Table. */
85 std::vector<SSID> SSIT;
86
116 std::vector<SSID> SSIT;
117
118 /** Bit vector to tell if the SSIT has a valid entry. */
87 std::vector<bool> validSSIT;
88
119 std::vector<bool> validSSIT;
120
121 /** Last Fetched Store Table. */
89 std::vector<InstSeqNum> LFST;
90
122 std::vector<InstSeqNum> LFST;
123
124 /** Bit vector to tell if the LFST has a valid entry. */
91 std::vector<bool> validLFST;
92
125 std::vector<bool> validLFST;
126
127 /** Map of stores that have been inserted into the store set, but
128 * not yet issued or squashed.
129 */
93 std::map<InstSeqNum, int, ltseqnum> storeList;
94
95 typedef std::map<InstSeqNum, int, ltseqnum>::iterator SeqNumMapIt;
96
130 std::map<InstSeqNum, int, ltseqnum> storeList;
131
132 typedef std::map<InstSeqNum, int, ltseqnum>::iterator SeqNumMapIt;
133
134 /** Store Set ID Table size, in entries. */
97 int SSITSize;
98
135 int SSITSize;
136
137 /** Last Fetched Store Table size, in entries. */
99 int LFSTSize;
100
138 int LFSTSize;
139
140 /** Mask to obtain the index. */
101 int indexMask;
102
103 // HACK: Hardcoded for now.
104 int offsetBits;
105};
106
107#endif // __CPU_O3_STORE_SET_HH__
141 int indexMask;
142
143 // HACK: Hardcoded for now.
144 int offsetBits;
145};
146
147#endif // __CPU_O3_STORE_SET_HH__