scoreboard.hh revision 12105 
1/*
2 * Copyright (c) 2005-2006 The Regents of The University of Michigan
3 * Copyright (c) 2013 Advanced Micro Devices, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Korey Sewell
30 *          Kevin Lim
31 *          Steve Reinhardt
32 */
33
34#ifndef __CPU_O3_SCOREBOARD_HH__
35#define __CPU_O3_SCOREBOARD_HH__
36
37#include <iostream>
38#include <utility>
39#include <vector>
40
41#include "base/trace.hh"
42#include "config/the_isa.hh"
43#include "cpu/o3/comm.hh"
44#include "debug/Scoreboard.hh"
45
46/**
47 * Implements a simple scoreboard to track which registers are
48 * ready. This class operates on the unified physical register space,
49 * because the different classes of registers do not need to be distinguished.
50 * Registers being part of a fixed mapping are always considered ready.
51 */
52class Scoreboard
53{
54  private:
55    /** The object name, for DPRINTF.  We have to declare this
56     *  explicitly because Scoreboard is not a SimObject. */
57    const std::string _name;
58
59    /** Scoreboard of physical integer registers, saying whether or not they
60     *  are ready. */
61    std::vector<bool> regScoreBoard;
62
63    /** The number of actual physical registers */
64    unsigned numPhysRegs;
65
66  public:
67    /** Constructs a scoreboard.
68     *  @param _numPhysicalRegs Number of physical registers.
69     *  @param _numMiscRegs Number of miscellaneous registers.
70     */
71    Scoreboard(const std::string &_my_name,
72               unsigned _numPhysicalRegs);
73
74    /** Destructor. */
75    ~Scoreboard() {}
76
77    /** Returns the name of the scoreboard. */
78    std::string name() const { return _name; };
79
80    /** Checks if the register is ready. */
81    bool getReg(PhysRegIdPtr phys_reg) const
82    {
83        assert(phys_reg->flatIdx < numPhysRegs);
84
85        if (phys_reg->isFixedMapping()) {
86            // Fixed mapping regs are always ready
87            return true;
88        }
89
90        bool ready = regScoreBoard[phys_reg->flatIdx];
91
92        if (phys_reg->isZeroReg())
93            assert(ready);
94
95        return ready;
96    }
97
98    /** Sets the register as ready. */
99    void setReg(PhysRegIdPtr phys_reg)
100    {
101        assert(phys_reg->flatIdx < numPhysRegs);
102
103        if (phys_reg->isFixedMapping()) {
104            // Fixed mapping regs are always ready, ignore attempts to change
105            // that
106            return;
107        }
108
109        DPRINTF(Scoreboard, "Setting reg %i (%s) as ready\n", phys_reg->regIdx,
110                RegClassStrings[phys_reg->regClass]);
111
112        regScoreBoard[phys_reg->flatIdx] = true;
113    }
114
115    /** Sets the register as not ready. */
116    void unsetReg(PhysRegIdPtr phys_reg)
117    {
118        assert(phys_reg->flatIdx < numPhysRegs);
119
120        if (phys_reg->isFixedMapping()) {
121            // Fixed mapping regs are always ready, ignore attempts to
122            // change that
123            return;
124        }
125
126        // zero reg should never be marked unready
127        if (phys_reg->isZeroReg())
128            return;
129
130        regScoreBoard[phys_reg->flatIdx] = false;
131    }
132
133};
134
135#endif
136