store_set.cc revision 2670:9107b8bd08cd 
1/*
2 * Copyright (c) 2004-2006 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
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#include "base/trace.hh"
32#include "cpu/o3/store_set.hh"
33
34StoreSet::StoreSet(int _SSIT_size, int _LFST_size)
35    : SSITSize(_SSIT_size), LFSTSize(_LFST_size)
36{
37    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
38    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
39            SSITSize, LFSTSize);
40
41    SSIT.resize(SSITSize);
42
43    validSSIT.resize(SSITSize);
44
45    for (int i = 0; i < SSITSize; ++i)
46        validSSIT[i] = false;
47
48    LFST.resize(LFSTSize);
49
50    validLFST.resize(LFSTSize);
51
52    for (int i = 0; i < LFSTSize; ++i) {
53        validLFST[i] = false;
54        LFST[i] = 0;
55    }
56
57    indexMask = SSITSize - 1;
58
59    offsetBits = 2;
60}
61
62StoreSet::~StoreSet()
63{
64}
65
66void
67StoreSet::init(int _SSIT_size, int _LFST_size)
68{
69    SSITSize = _SSIT_size;
70    LFSTSize = _LFST_size;
71
72    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
73    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
74            SSITSize, LFSTSize);
75
76    SSIT.resize(SSITSize);
77
78    validSSIT.resize(SSITSize);
79
80    for (int i = 0; i < SSITSize; ++i)
81        validSSIT[i] = false;
82
83    LFST.resize(LFSTSize);
84
85    validLFST.resize(LFSTSize);
86
87    for (int i = 0; i < LFSTSize; ++i) {
88        validLFST[i] = false;
89        LFST[i] = 0;
90    }
91
92    indexMask = SSITSize - 1;
93
94    offsetBits = 2;
95}
96
97
98void
99StoreSet::violation(Addr store_PC, Addr load_PC)
100{
101    int load_index = calcIndex(load_PC);
102    int store_index = calcIndex(store_PC);
103
104    assert(load_index < SSITSize && store_index < SSITSize);
105
106    bool valid_load_SSID = validSSIT[load_index];
107    bool valid_store_SSID = validSSIT[store_index];
108
109    if (!valid_load_SSID && !valid_store_SSID) {
110        // Calculate a new SSID here.
111        SSID new_set = calcSSID(load_PC);
112
113        validSSIT[load_index] = true;
114
115        SSIT[load_index] = new_set;
116
117        validSSIT[store_index] = true;
118
119        SSIT[store_index] = new_set;
120
121        assert(new_set < LFSTSize);
122
123        DPRINTF(StoreSet, "StoreSet: Neither load nor store had a valid "
124                "storeset, creating a new one: %i for load %#x, store %#x\n",
125                new_set, load_PC, store_PC);
126    } else if (valid_load_SSID && !valid_store_SSID) {
127        SSID load_SSID = SSIT[load_index];
128
129        validSSIT[store_index] = true;
130
131        SSIT[store_index] = load_SSID;
132
133        assert(load_SSID < LFSTSize);
134
135        DPRINTF(StoreSet, "StoreSet: Load had a valid store set.  Adding "
136                "store to that set: %i for load %#x, store %#x\n",
137                load_SSID, load_PC, store_PC);
138    } else if (!valid_load_SSID && valid_store_SSID) {
139        SSID store_SSID = SSIT[store_index];
140
141        validSSIT[load_index] = true;
142
143        SSIT[load_index] = store_SSID;
144
145        DPRINTF(StoreSet, "StoreSet: Store had a valid store set: %i for "
146                "load %#x, store %#x\n",
147                store_SSID, load_PC, store_PC);
148    } else {
149        SSID load_SSID = SSIT[load_index];
150        SSID store_SSID = SSIT[store_index];
151
152        assert(load_SSID < LFSTSize && store_SSID < LFSTSize);
153
154        // The store set with the lower number wins
155        if (store_SSID > load_SSID) {
156            SSIT[store_index] = load_SSID;
157
158            DPRINTF(StoreSet, "StoreSet: Load had smaller store set: %i; "
159                    "for load %#x, store %#x\n",
160                    load_SSID, load_PC, store_PC);
161        } else {
162            SSIT[load_index] = store_SSID;
163
164            DPRINTF(StoreSet, "StoreSet: Store had smaller store set: %i; "
165                    "for load %#x, store %#x\n",
166                    store_SSID, load_PC, store_PC);
167        }
168    }
169}
170
171void
172StoreSet::insertLoad(Addr load_PC, InstSeqNum load_seq_num)
173{
174    // Does nothing.
175    return;
176}
177
178void
179StoreSet::insertStore(Addr store_PC, InstSeqNum store_seq_num,
180                      unsigned tid)
181{
182    int index = calcIndex(store_PC);
183
184    int store_SSID;
185
186    assert(index < SSITSize);
187
188    if (!validSSIT[index]) {
189        // Do nothing if there's no valid entry.
190        return;
191    } else {
192        store_SSID = SSIT[index];
193
194        assert(store_SSID < LFSTSize);
195
196        // Update the last store that was fetched with the current one.
197        LFST[store_SSID] = store_seq_num;
198
199        validLFST[store_SSID] = 1;
200
201        storeList[store_seq_num] = store_SSID;
202
203        DPRINTF(StoreSet, "Store %#x updated the LFST, SSID: %i\n",
204                store_PC, store_SSID);
205    }
206}
207
208InstSeqNum
209StoreSet::checkInst(Addr PC)
210{
211    int index = calcIndex(PC);
212
213    int inst_SSID;
214
215    assert(index < SSITSize);
216
217    if (!validSSIT[index]) {
218        DPRINTF(StoreSet, "Inst %#x with index %i had no SSID\n",
219                PC, index);
220
221        // Return 0 if there's no valid entry.
222        return 0;
223    } else {
224        inst_SSID = SSIT[index];
225
226        assert(inst_SSID < LFSTSize);
227
228        if (!validLFST[inst_SSID]) {
229
230            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had no "
231                    "dependency\n", PC, index, inst_SSID);
232
233            return 0;
234        } else {
235            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had LFST "
236                    "inum of %i\n", PC, index, inst_SSID, LFST[inst_SSID]);
237
238            return LFST[inst_SSID];
239        }
240    }
241}
242
243void
244StoreSet::issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store)
245{
246    // This only is updated upon a store being issued.
247    if (!is_store) {
248        return;
249    }
250
251    int index = calcIndex(issued_PC);
252
253    int store_SSID;
254
255    assert(index < SSITSize);
256
257    SeqNumMapIt store_list_it = storeList.find(issued_seq_num);
258
259    if (store_list_it != storeList.end()) {
260        storeList.erase(store_list_it);
261    }
262
263    // Make sure the SSIT still has a valid entry for the issued store.
264    if (!validSSIT[index]) {
265        return;
266    }
267
268    store_SSID = SSIT[index];
269
270    assert(store_SSID < LFSTSize);
271
272    // If the last fetched store in the store set refers to the store that
273    // was just issued, then invalidate the entry.
274    if (validLFST[store_SSID] && LFST[store_SSID] == issued_seq_num) {
275        DPRINTF(StoreSet, "StoreSet: store invalidated itself in LFST.\n");
276        validLFST[store_SSID] = false;
277    }
278}
279
280void
281StoreSet::squash(InstSeqNum squashed_num, unsigned tid)
282{
283    DPRINTF(StoreSet, "StoreSet: Squashing until inum %i\n",
284            squashed_num);
285
286    int idx;
287    SeqNumMapIt store_list_it = storeList.begin();
288
289    //@todo:Fix to only delete from correct thread
290    while (!storeList.empty()) {
291        idx = (*store_list_it).second;
292
293        if ((*store_list_it).first <= squashed_num) {
294            break;
295        }
296
297        bool younger = LFST[idx] > squashed_num;
298
299        if (validLFST[idx] && younger) {
300            DPRINTF(StoreSet, "Squashed [sn:%lli]\n", LFST[idx]);
301            validLFST[idx] = false;
302
303            storeList.erase(store_list_it++);
304        } else if (!validLFST[idx] && younger) {
305            storeList.erase(store_list_it++);
306        }
307    }
308}
309
310void
311StoreSet::clear()
312{
313    for (int i = 0; i < SSITSize; ++i) {
314        validSSIT[i] = false;
315    }
316
317    for (int i = 0; i < LFSTSize; ++i) {
318        validLFST[i] = false;
319    }
320
321    storeList.clear();
322}
323