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

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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