store_set.cc revision 2329 
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
29#include "base/trace.hh"
30#include "cpu/o3/store_set.hh"
31
32StoreSet::StoreSet(int _SSIT_size, int _LFST_size)
33    : SSITSize(_SSIT_size), LFSTSize(_LFST_size)
34{
35    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
36    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
37            SSITSize, LFSTSize);
38
39    SSIT.resize(SSITSize);
40
41    validSSIT.resize(SSITSize);
42
43    for (int i = 0; i < SSITSize; ++i)
44        validSSIT[i] = false;
45
46    LFST.resize(LFSTSize);
47
48    validLFST.resize(LFSTSize);
49
50    for (int i = 0; i < LFSTSize; ++i) {
51        validLFST[i] = false;
52        LFST[i] = 0;
53    }
54
55    indexMask = SSITSize - 1;
56
57    offsetBits = 2;
58}
59
60StoreSet::~StoreSet()
61{
62}
63
64void
65StoreSet::init(int _SSIT_size, int _LFST_size)
66{
67    SSITSize = _SSIT_size;
68    LFSTSize = _LFST_size;
69
70    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
71    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
72            SSITSize, LFSTSize);
73
74    SSIT.resize(SSITSize);
75
76    validSSIT.resize(SSITSize);
77
78    for (int i = 0; i < SSITSize; ++i)
79        validSSIT[i] = false;
80
81    LFST.resize(LFSTSize);
82
83    validLFST.resize(LFSTSize);
84
85    for (int i = 0; i < LFSTSize; ++i) {
86        validLFST[i] = false;
87        LFST[i] = 0;
88    }
89
90    indexMask = SSITSize - 1;
91
92    offsetBits = 2;
93}
94
95
96void
97StoreSet::violation(Addr store_PC, Addr load_PC)
98{
99    int load_index = calcIndex(load_PC);
100    int store_index = calcIndex(store_PC);
101
102    assert(load_index < SSITSize && store_index < SSITSize);
103
104    bool valid_load_SSID = validSSIT[load_index];
105    bool valid_store_SSID = validSSIT[store_index];
106
107    if (!valid_load_SSID && !valid_store_SSID) {
108        // Calculate a new SSID here.
109        SSID new_set = calcSSID(load_PC);
110
111        validSSIT[load_index] = true;
112
113        SSIT[load_index] = new_set;
114
115        validSSIT[store_index] = true;
116
117        SSIT[store_index] = new_set;
118
119        assert(new_set < LFSTSize);
120
121        DPRINTF(StoreSet, "StoreSet: Neither load nor store had a valid "
122                "storeset, creating a new one: %i for load %#x, store %#x\n",
123                new_set, load_PC, store_PC);
124    } else if (valid_load_SSID && !valid_store_SSID) {
125        SSID load_SSID = SSIT[load_index];
126
127        validSSIT[store_index] = true;
128
129        SSIT[store_index] = load_SSID;
130
131        assert(load_SSID < LFSTSize);
132
133        DPRINTF(StoreSet, "StoreSet: Load had a valid store set.  Adding "
134                "store to that set: %i for load %#x, store %#x\n",
135                load_SSID, load_PC, store_PC);
136    } else if (!valid_load_SSID && valid_store_SSID) {
137        SSID store_SSID = SSIT[store_index];
138
139        validSSIT[load_index] = true;
140
141        SSIT[load_index] = store_SSID;
142
143        DPRINTF(StoreSet, "StoreSet: Store had a valid store set: %i for "
144                "load %#x, store %#x\n",
145                store_SSID, load_PC, store_PC);
146    } else {
147        SSID load_SSID = SSIT[load_index];
148        SSID store_SSID = SSIT[store_index];
149
150        assert(load_SSID < LFSTSize && store_SSID < LFSTSize);
151
152        // The store set with the lower number wins
153        if (store_SSID > load_SSID) {
154            SSIT[store_index] = load_SSID;
155
156            DPRINTF(StoreSet, "StoreSet: Load had smaller store set: %i; "
157                    "for load %#x, store %#x\n",
158                    load_SSID, load_PC, store_PC);
159        } else {
160            SSIT[load_index] = store_SSID;
161
162            DPRINTF(StoreSet, "StoreSet: Store had smaller store set: %i; "
163                    "for load %#x, store %#x\n",
164                    store_SSID, load_PC, store_PC);
165        }
166    }
167}
168
169void
170StoreSet::insertLoad(Addr load_PC, InstSeqNum load_seq_num)
171{
172    // Does nothing.
173    return;
174}
175
176void
177StoreSet::insertStore(Addr store_PC, InstSeqNum store_seq_num,
178                      unsigned tid)
179{
180    int index = calcIndex(store_PC);
181
182    int store_SSID;
183
184    assert(index < SSITSize);
185
186    if (!validSSIT[index]) {
187        // Do nothing if there's no valid entry.
188        return;
189    } else {
190        store_SSID = SSIT[index];
191
192        assert(store_SSID < LFSTSize);
193
194        // Update the last store that was fetched with the current one.
195        LFST[store_SSID] = store_seq_num;
196
197        validLFST[store_SSID] = 1;
198
199        storeList[store_seq_num] = store_SSID;
200
201        DPRINTF(StoreSet, "Store %#x updated the LFST, SSID: %i\n",
202                store_PC, store_SSID);
203    }
204}
205
206InstSeqNum
207StoreSet::checkInst(Addr PC)
208{
209    int index = calcIndex(PC);
210
211    int inst_SSID;
212
213    assert(index < SSITSize);
214
215    if (!validSSIT[index]) {
216        DPRINTF(StoreSet, "Inst %#x with index %i had no SSID\n",
217                PC, index);
218
219        // Return 0 if there's no valid entry.
220        return 0;
221    } else {
222        inst_SSID = SSIT[index];
223
224        assert(inst_SSID < LFSTSize);
225
226        if (!validLFST[inst_SSID]) {
227
228            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had no "
229                    "dependency\n", PC, index, inst_SSID);
230
231            return 0;
232        } else {
233            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had LFST "
234                    "inum of %i\n", PC, index, inst_SSID, LFST[inst_SSID]);
235
236            return LFST[inst_SSID];
237        }
238    }
239}
240
241void
242StoreSet::issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store)
243{
244    // This only is updated upon a store being issued.
245    if (!is_store) {
246        return;
247    }
248
249    int index = calcIndex(issued_PC);
250
251    int store_SSID;
252
253    assert(index < SSITSize);
254
255    SeqNumMapIt store_list_it = storeList.find(issued_seq_num);
256
257    if (store_list_it != storeList.end()) {
258        storeList.erase(store_list_it);
259    }
260
261    // Make sure the SSIT still has a valid entry for the issued store.
262    if (!validSSIT[index]) {
263        return;
264    }
265
266    store_SSID = SSIT[index];
267
268    assert(store_SSID < LFSTSize);
269
270    // If the last fetched store in the store set refers to the store that
271    // was just issued, then invalidate the entry.
272    if (validLFST[store_SSID] && LFST[store_SSID] == issued_seq_num) {
273        DPRINTF(StoreSet, "StoreSet: store invalidated itself in LFST.\n");
274        validLFST[store_SSID] = false;
275    }
276}
277
278void
279StoreSet::squash(InstSeqNum squashed_num, unsigned tid)
280{
281    DPRINTF(StoreSet, "StoreSet: Squashing until inum %i\n",
282            squashed_num);
283
284    int idx;
285    SeqNumMapIt store_list_it = storeList.begin();
286
287    //@todo:Fix to only delete from correct thread
288    while (!storeList.empty()) {
289        idx = (*store_list_it).second;
290
291        if ((*store_list_it).first <= squashed_num) {
292            break;
293        }
294
295        bool younger = LFST[idx] > squashed_num;
296
297        if (validLFST[idx] && younger) {
298            DPRINTF(StoreSet, "Squashed [sn:%lli]\n", LFST[idx]);
299            validLFST[idx] = false;
300
301            storeList.erase(store_list_it++);
302        } else if (!validLFST[idx] && younger) {
303            storeList.erase(store_list_it++);
304        }
305    }
306}
307
308void
309StoreSet::clear()
310{
311    for (int i = 0; i < SSITSize; ++i) {
312        validSSIT[i] = false;
313    }
314
315    for (int i = 0; i < LFSTSize; ++i) {
316        validLFST[i] = false;
317    }
318
319    storeList.clear();
320}
321