btb.hh revision 1061 
1#ifndef __BTB_HH__
2#define __BTB_HH__
3
4// For Addr type.
5#include "arch/alpha/isa_traits.hh"
6
7class DefaultBTB
8{
9  private:
10    struct BTBEntry
11    {
12        BTBEntry()
13            : tag(0), target(0), valid(false)
14        {
15        }
16
17        Addr tag;
18        Addr target;
19        bool valid;
20    };
21
22  public:
23    DefaultBTB(unsigned numEntries, unsigned tagBits,
24               unsigned instShiftAmt);
25
26    Addr lookup(const Addr &inst_PC);
27
28    bool valid(const Addr &inst_PC);
29
30    void update(const Addr &inst_PC, const Addr &target_PC);
31
32  private:
33    inline unsigned getIndex(const Addr &inst_PC);
34
35    inline Addr getTag(const Addr &inst_PC);
36
37    BTBEntry *btb;
38
39    unsigned numEntries;
40
41    unsigned idxMask;
42
43    unsigned tagBits;
44
45    unsigned tagMask;
46
47    unsigned instShiftAmt;
48
49    unsigned tagShiftAmt;
50};
51
52#endif // __BTB_HH__
53