14 * Copyright (c) 2006 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Kevin Lim
41 */
42
43#ifndef __CPU_O3_FU_POOL_HH__
44#define __CPU_O3_FU_POOL_HH__
45
46#include <bitset>
47#include <list>
48#include <string>
49#include <vector>
50
51#include "cpu/op_class.hh"
52#include "params/FUPool.hh"
53#include "sim/sim_object.hh"
54
55class FUDesc;
56class FuncUnit;
57
58/**
59 * Pool of FU's, specific to the new CPU model. The old FU pool had lists of
60 * free units and busy units, and whenever a FU was needed it would iterate
61 * through the free units to find a FU that provided the capability. This pool
62 * has lists of units specific to each of the capabilities, and whenever a FU
63 * is needed, it iterates through that list to find a free unit. The previous
64 * FU pool would have to be ticked each cycle to update which units became
65 * free. This FU pool lets the IEW stage handle freeing units, which frees
66 * them as their scheduled execution events complete. This limits units in this
67 * model to either have identical issue and op latencies, or 1 cycle issue
68 * latencies.
69 */
70class FUPool : public SimObject
71{
72 private:
73 /** Maximum op execution latencies, per op class. */
74 Cycles maxOpLatencies[Num_OpClasses];
75 /** Maximum issue latencies, per op class. */
76 Cycles maxIssueLatencies[Num_OpClasses];
77
78 /** Bitvector listing capabilities of this FU pool. */
79 std::bitset<Num_OpClasses> capabilityList;
80
81 /** Bitvector listing which FUs are busy. */
82 std::vector<bool> unitBusy;
83
84 /** List of units to be freed at the end of this cycle. */
85 std::vector<int> unitsToBeFreed;
86
87 /**
88 * Class that implements a circular queue to hold FU indices. The hope is
89 * that FUs that have been just used will be moved to the end of the queue
90 * by iterating through it, thus leaving free units at the head of the
91 * queue.
92 */
93 class FUIdxQueue {
94 public:
95 /** Constructs a circular queue of FU indices. */
96 FUIdxQueue()
97 : idx(0), size(0)
98 { }
99
100 /** Adds a FU to the queue. */
101 inline void addFU(int fu_idx);
102
103 /** Returns the index of the FU at the head of the queue, and changes
104 * the index to the next element.
105 */
106 inline int getFU();
107
108 private:
109 /** Circular queue index. */
110 int idx;
111
112 /** Size of the queue. */
113 int size;
114
115 /** Queue of FU indices. */
116 std::vector<int> funcUnitsIdx;
117 };
118
119 /** Per op class queues of FUs that provide that capability. */
120 FUIdxQueue fuPerCapList[Num_OpClasses];
121
122 /** Number of FUs. */
123 int numFU;
124
125 /** Functional units. */
126 std::vector<FuncUnit *> funcUnits;
127
128 typedef std::vector<FuncUnit *>::iterator fuListIterator;
129
130 public:
131 typedef FUPoolParams Params;
132 /** Constructs a FU pool. */
133 FUPool(const Params *p);
134 ~FUPool();
135
136 /** Annotates units that provide memory operations. Included only because
137 * old FU pool provided this function.
138 */
139 void annotateMemoryUnits(Cycles hit_latency);
140
141 /**
142 * Gets a FU providing the requested capability. Will mark the unit as busy,
143 * but leaves the freeing of the unit up to the IEW stage.
144 * @param capability The capability requested.
145 * @return Returns -2 if the FU pool does not have the capability, -1 if
146 * there is no free FU, and the FU's index otherwise.
147 */
148 int getUnit(OpClass capability);
149
150 /** Frees a FU at the end of this cycle. */
151 void freeUnitNextCycle(int fu_idx);
152
153 /** Frees all FUs on the list. */
154 void processFreeUnits();
155
156 /** Returns the total number of FUs. */
157 int size() { return numFU; }
158
159 /** Debugging function used to dump FU information. */
160 void dump();
161
162 /** Returns the operation execution latency of the given capability. */
163 Cycles getOpLatency(OpClass capability) {
164 return maxOpLatencies[capability];
165 }
166
167 /** Returns the issue latency of the given capability. */
168 Cycles getIssueLatency(OpClass capability) {
169 return maxIssueLatencies[capability];
170 }
171
|