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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19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 */
30
31#ifndef __CPU_O3_CPU_FREE_LIST_HH__
32#define __CPU_O3_CPU_FREE_LIST_HH__
33
34#include <iostream>
35#include <queue>
36
37#include "arch/isa_traits.hh"
38#include "base/trace.hh"
39#include "base/traceflags.hh"
40#include "cpu/o3/comm.hh"
41
42/**
43 * FreeList class that simply holds the list of free integer and floating
44 * point registers. Can request for a free register of either type, and
45 * also send back free registers of either type. This is a very simple
46 * class, but it should be sufficient for most implementations. Like all
47 * other classes, it assumes that the indices for the floating point
48 * registers starts after the integer registers end. Hence the variable
49 * numPhysicalIntRegs is logically equivalent to the baseFP dependency.
50 * Note that
51 * while this most likely should be called FreeList, the name "FreeList"
52 * is used in a typedef within the CPU Policy, and therefore no class
53 * can be named simply "FreeList".
54 * @todo: Give a better name to the base FP dependency.
55 */
56class SimpleFreeList
57{
58 private:
59 /** The list of free integer registers. */
60 std::queue<PhysRegIndex> freeIntRegs;
61

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72 int numLogicalFloatRegs;
73
74 /** Number of physical floating point registers. */
75 int numPhysicalFloatRegs;
76
77 /** Total number of physical registers. */
78 int numPhysicalRegs;
79
80 /** DEBUG stuff below. */
81 std::vector<int> freeIntRegsScoreboard;
82
83 std::vector<bool> freeFloatRegsScoreboard;
84
85 public:
86 SimpleFreeList(unsigned _numLogicalIntRegs,
87 unsigned _numPhysicalIntRegs,
88 unsigned _numLogicalFloatRegs,
89 unsigned _numPhysicalFloatRegs);
90
91 inline PhysRegIndex getIntReg();
92
93 inline PhysRegIndex getFloatReg();
94
95 inline void addReg(PhysRegIndex freed_reg);
96
97 inline void addIntReg(PhysRegIndex freed_reg);
98
99 inline void addFloatReg(PhysRegIndex freed_reg);
100
101 bool hasFreeIntRegs()
102 { return !freeIntRegs.empty(); }
103
104 bool hasFreeFloatRegs()
105 { return !freeFloatRegs.empty(); }
106
107 int numFreeIntRegs()
108 { return freeIntRegs.size(); }
109
110 int numFreeFloatRegs()
111 { return freeFloatRegs.size(); }
112};
113
114inline PhysRegIndex
115SimpleFreeList::getIntReg()
116{
117 DPRINTF(Rename, "FreeList: Trying to get free integer register.\n");
118 if (freeIntRegs.empty()) {
119 panic("No free integer registers!");
120 }
121
122 PhysRegIndex free_reg = freeIntRegs.front();
123
124 freeIntRegs.pop();
125
126 // DEBUG
127 assert(freeIntRegsScoreboard[free_reg]);
128 freeIntRegsScoreboard[free_reg] = 0;
129
130 return(free_reg);
131}
132
133inline PhysRegIndex
134SimpleFreeList::getFloatReg()
135{
136 DPRINTF(Rename, "FreeList: Trying to get free float register.\n");
137 if (freeFloatRegs.empty()) {
138 panic("No free integer registers!");
139 }
140
141 PhysRegIndex free_reg = freeFloatRegs.front();
142
143 freeFloatRegs.pop();
144
145 // DEBUG
146 assert(freeFloatRegsScoreboard[free_reg]);
147 freeFloatRegsScoreboard[free_reg] = 0;
148
149 return(free_reg);
150}
151
152inline void
153SimpleFreeList::addReg(PhysRegIndex freed_reg)
154{
155 DPRINTF(Rename, "Freelist: Freeing register %i.\n", freed_reg);
156 //Might want to add in a check for whether or not this register is
157 //already in there. A bit vector or something similar would be useful.
158 if (freed_reg < numPhysicalIntRegs) {
159 freeIntRegs.push(freed_reg);
160
161 // DEBUG
162 assert(freeIntRegsScoreboard[freed_reg] == false);
163 freeIntRegsScoreboard[freed_reg] = 1;
164 } else if (freed_reg < numPhysicalRegs) {
165 freeFloatRegs.push(freed_reg);
166
167 // DEBUG
168 assert(freeFloatRegsScoreboard[freed_reg] == false);
169 freeFloatRegsScoreboard[freed_reg] = 1;
170 }
171}
172
173inline void
174SimpleFreeList::addIntReg(PhysRegIndex freed_reg)
175{
176 DPRINTF(Rename, "Freelist: Freeing int register %i.\n", freed_reg);
177
178 // DEBUG
179 assert(!freeIntRegsScoreboard[freed_reg]);
180 freeIntRegsScoreboard[freed_reg] = 1;
181
182 freeIntRegs.push(freed_reg);
183}
184
185inline void
186SimpleFreeList::addFloatReg(PhysRegIndex freed_reg)
187{
188 DPRINTF(Rename, "Freelist: Freeing float register %i.\n", freed_reg);
189
190 // DEBUG
191 assert(!freeFloatRegsScoreboard[freed_reg]);
192 freeFloatRegsScoreboard[freed_reg] = 1;
193
194 freeFloatRegs.push(freed_reg);
195}
196
197#endif // __CPU_O3_CPU_FREE_LIST_HH__