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;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the

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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
29#include "base/trace.hh"
30#include "cpu/o3/store_set.hh"
31
32StoreSet::StoreSet(int _SSIT_size, int _LFST_size)
33 : SSIT_size(_SSIT_size), LFST_size(_LFST_size)
34{
35 DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
36 DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
37 SSIT_size, LFST_size);
38
39 SSIT = new SSID[SSIT_size];
40
41 validSSIT.resize(SSIT_size);
42
43 for (int i = 0; i < SSIT_size; ++i)
44 validSSIT[i] = false;
45
46 LFST = new InstSeqNum[LFST_size];
47
48 validLFST.resize(LFST_size);
49
50 SSCounters = new int[LFST_size];
51
52 for (int i = 0; i < LFST_size; ++i)
53 {
54 validLFST[i] = false;
55 SSCounters[i] = 0;
56 }
57
58 index_mask = SSIT_size - 1;
59
60 offset_bits = 2;
61}
62
63void
64StoreSet::violation(Addr store_PC, Addr load_PC)
65{
66 int load_index = calcIndex(load_PC);
67 int store_index = calcIndex(store_PC);
68
69 assert(load_index < SSIT_size && store_index < SSIT_size);
70
71 bool valid_load_SSID = validSSIT[load_index];
72 bool valid_store_SSID = validSSIT[store_index];
73
74 if (!valid_load_SSID && !valid_store_SSID) {
75 // Calculate a new SSID here.
76 SSID new_set = calcSSID(load_PC);
77
78 validSSIT[load_index] = true;
79
80 SSIT[load_index] = new_set;
81
82 validSSIT[store_index] = true;
83
84 SSIT[store_index] = new_set;
85
86 assert(new_set < LFST_size);
87
88 SSCounters[new_set]++;
89
90
91 DPRINTF(StoreSet, "StoreSet: Neither load nor store had a valid "
92 "storeset, creating a new one: %i for load %#x, store %#x\n",
93 new_set, load_PC, store_PC);
94 } else if (valid_load_SSID && !valid_store_SSID) {
95 SSID load_SSID = SSIT[load_index];
96
97 validSSIT[store_index] = true;
98
99 SSIT[store_index] = load_SSID;
100
101 assert(load_SSID < LFST_size);
102
103 SSCounters[load_SSID]++;
104
105 DPRINTF(StoreSet, "StoreSet: Load had a valid store set. Adding "
106 "store to that set: %i for load %#x, store %#x\n",
107 load_SSID, load_PC, store_PC);
108 } else if (!valid_load_SSID && valid_store_SSID) {
109 SSID store_SSID = SSIT[store_index];
110
111 validSSIT[load_index] = true;
112
113 SSIT[load_index] = store_SSID;
114
115 // Because we are having a load point to an already existing set,
116 // the size of the store set is not incremented.
117
118 DPRINTF(StoreSet, "StoreSet: Store had a valid store set: %i for "
119 "load %#x, store %#x\n",
120 store_SSID, load_PC, store_PC);
121 } else {
122 SSID load_SSID = SSIT[load_index];
123 SSID store_SSID = SSIT[store_index];
124
125 assert(load_SSID < LFST_size && store_SSID < LFST_size);
126
127 int load_SS_size = SSCounters[load_SSID];
128 int store_SS_size = SSCounters[store_SSID];
129
130 // If the load has the bigger store set, then assign the store
131 // to the same store set as the load. Otherwise vice-versa.
132 if (load_SS_size > store_SS_size) {
133 SSIT[store_index] = load_SSID;
134
135 SSCounters[load_SSID]++;
136 SSCounters[store_SSID]--;
137
138 DPRINTF(StoreSet, "StoreSet: Load had bigger store set: %i; "
139 "for load %#x, store %#x\n",
140 load_SSID, load_PC, store_PC);
141 } else {
142 SSIT[load_index] = store_SSID;
143
144 SSCounters[store_SSID]++;
145 SSCounters[load_SSID]--;
146
147 DPRINTF(StoreSet, "StoreSet: Store had bigger store set: %i; "
148 "for load %#x, store %#x\n",
149 store_SSID, load_PC, store_PC);
150 }
151 }
152}
153
154void
155StoreSet::insertLoad(Addr load_PC, InstSeqNum load_seq_num)
156{
157 // Does nothing.
158 return;
159}
160
161void
162StoreSet::insertStore(Addr store_PC, InstSeqNum store_seq_num)
163{
164 int index = calcIndex(store_PC);
165
166 int store_SSID;
167
168 assert(index < SSIT_size);
169
170 if (!validSSIT[index]) {
171 // Do nothing if there's no valid entry.
172 return;
173 } else {
174 store_SSID = SSIT[index];
175
176 assert(store_SSID < LFST_size);
177
178 // Update the last store that was fetched with the current one.
179 LFST[store_SSID] = store_seq_num;
180
181 validLFST[store_SSID] = 1;
182
183 DPRINTF(StoreSet, "Store %#x updated the LFST, SSID: %i\n",
184 store_PC, store_SSID);
185 }
186}
187
188InstSeqNum
189StoreSet::checkInst(Addr PC)
190{
191 int index = calcIndex(PC);
192
193 int inst_SSID;
194
195 assert(index < SSIT_size);
196
197 if (!validSSIT[index]) {
198 DPRINTF(StoreSet, "Inst %#x with index %i had no SSID\n",
199 PC, index);
200
201 // Return 0 if there's no valid entry.
202 return 0;
203 } else {
204 inst_SSID = SSIT[index];
205
206 assert(inst_SSID < LFST_size);
207
208 if (!validLFST[inst_SSID]) {
209
210 DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had no "
211 "dependency\n", PC, index, inst_SSID);
212
213 return 0;
214 } else {

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227 if (!is_store) {
228 return;
229 }
230
231 int index = calcIndex(issued_PC);
232
233 int store_SSID;
234
235 assert(index < SSIT_size);
236
237 // Make sure the SSIT still has a valid entry for the issued store.
238 if (!validSSIT[index]) {
239 return;
240 }
241
242 store_SSID = SSIT[index];
243
244 assert(store_SSID < LFST_size);
245
246 // If the last fetched store in the store set refers to the store that
247 // was just issued, then invalidate the entry.
248 if (validLFST[store_SSID] && LFST[store_SSID] == issued_seq_num) {
249 DPRINTF(StoreSet, "StoreSet: store invalidated itself in LFST.\n");
250 validLFST[store_SSID] = false;
251 }
252}
253
254void
255StoreSet::squash(InstSeqNum squashed_num)
256{
257 // Not really sure how to do this well.
258 // Generally this is small enough that it should be okay; short circuit
259 // evaluation should take care of invalid entries.
260
261 DPRINTF(StoreSet, "StoreSet: Squashing until inum %i\n",
262 squashed_num);
263
264 for (int i = 0; i < LFST_size; ++i) {
265 if (validLFST[i] && LFST[i] < squashed_num) {
266 validLFST[i] = false;
267 }
268 }
269}
270
271void
272StoreSet::clear()
273{
274 for (int i = 0; i < SSIT_size; ++i) {
275 validSSIT[i] = false;
276 }
277
278 for (int i = 0; i < LFST_size; ++i) {
279 validLFST[i] = false;
280 }
281}
282