1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
|
#include <vector>
#include "cpu/beta_cpu/rename_map.hh"
using namespace std;
// Todo: Consider making functions inline. Avoid having things that are
// using the zero register or misc registers from adding on the registers
// to the free list. Possibly remove the direct communication between
// this and the freelist. Considering making inline bool functions that
// determine if the register is a logical int, logical fp, physical int,
// physical fp, etc.
SimpleRenameMap::SimpleRenameMap(unsigned _numLogicalIntRegs,
unsigned _numPhysicalIntRegs,
unsigned _numLogicalFloatRegs,
unsigned _numPhysicalFloatRegs,
unsigned _numMiscRegs,
RegIndex _intZeroReg,
RegIndex _floatZeroReg)
: numLogicalIntRegs(_numLogicalIntRegs),
numPhysicalIntRegs(_numPhysicalIntRegs),
numLogicalFloatRegs(_numLogicalFloatRegs),
numPhysicalFloatRegs(_numPhysicalFloatRegs),
numMiscRegs(_numMiscRegs),
intZeroReg(_intZeroReg),
floatZeroReg(_floatZeroReg)
{
DPRINTF(Rename, "Rename: Creating rename map. Phys: %i / %i, Float: "
"%i / %i.\n", numLogicalIntRegs, numPhysicalIntRegs,
numLogicalFloatRegs, numPhysicalFloatRegs);
numLogicalRegs = numLogicalIntRegs + numLogicalFloatRegs;
numPhysicalRegs = numPhysicalIntRegs + numPhysicalFloatRegs;
//Create the rename maps, and their scoreboards.
intRenameMap = new RenameEntry[numLogicalIntRegs];
floatRenameMap = new RenameEntry[numLogicalRegs];
// Should combine this into one scoreboard.
intScoreboard.resize(numPhysicalIntRegs);
floatScoreboard.resize(numPhysicalRegs);
miscScoreboard.resize(numPhysicalRegs + numMiscRegs);
// Initialize the entries in the integer rename map to point to the
// physical registers of the same index, and consider each register
// ready until the first rename occurs.
for (RegIndex index = 0; index < numLogicalIntRegs; ++index)
{
intRenameMap[index].physical_reg = index;
intScoreboard[index] = 1;
}
// Initialize the rest of the physical registers (the ones that don't
// directly map to a logical register) as unready.
for (PhysRegIndex index = numLogicalIntRegs;
index < numPhysicalIntRegs;
++index)
{
intScoreboard[index] = 0;
}
int float_reg_idx = numPhysicalIntRegs;
// Initialize the entries in the floating point rename map to point to
// the physical registers of the same index, and consider each register
// ready until the first rename occurs.
// Although the index refers purely to architected registers, because
// the floating reg indices come after the integer reg indices, they
// may exceed the size of a normal RegIndex (short).
for (PhysRegIndex index = numLogicalIntRegs;
index < numLogicalRegs; ++index)
{
floatRenameMap[index].physical_reg = float_reg_idx++;
}
for (PhysRegIndex index = numPhysicalIntRegs;
index < numPhysicalIntRegs + numLogicalFloatRegs; ++index)
{
floatScoreboard[index] = 1;
}
// Initialize the rest of the physical registers (the ones that don't
// directly map to a logical register) as unready.
for (PhysRegIndex index = numPhysicalIntRegs + numLogicalFloatRegs;
index < numPhysicalRegs;
++index)
{
floatScoreboard[index] = 0;
}
// Initialize the entries in the misc register scoreboard to be ready.
for (PhysRegIndex index = numPhysicalRegs;
index < numPhysicalRegs + numMiscRegs; ++index)
{
miscScoreboard[index] = 1;
}
}
SimpleRenameMap::~SimpleRenameMap()
{
// Delete the rename maps as they were allocated with new.
delete [] intRenameMap;
delete [] floatRenameMap;
}
void
SimpleRenameMap::setFreeList(SimpleFreeList *fl_ptr)
{
//Setup the interface to the freelist.
freeList = fl_ptr;
}
// Don't allow this stage to fault; force that check to the rename stage.
// Simply ask to rename a logical register and get back a new physical
// register index.
SimpleRenameMap::RenameInfo
SimpleRenameMap::rename(RegIndex arch_reg)
{
PhysRegIndex renamed_reg;
PhysRegIndex prev_reg;
if (arch_reg < numLogicalIntRegs) {
// Record the current physical register that is renamed to the
// requested architected register.
prev_reg = intRenameMap[arch_reg].physical_reg;
// If it's not referencing the zero register, then mark the register
// as not ready.
if (arch_reg != intZeroReg) {
// Get a free physical register to rename to.
renamed_reg = freeList->getIntReg();
// Update the integer rename map.
intRenameMap[arch_reg].physical_reg = renamed_reg;
assert(renamed_reg >= 0 && renamed_reg < numPhysicalIntRegs);
// Mark register as not ready.
intScoreboard[renamed_reg] = false;
} else {
// Otherwise return the zero register so nothing bad happens.
renamed_reg = intZeroReg;
}
} else if (arch_reg < numLogicalRegs) {
// Subtract off the base offset for floating point registers.
// arch_reg = arch_reg - numLogicalIntRegs;
// Record the current physical register that is renamed to the
// requested architected register.
prev_reg = floatRenameMap[arch_reg].physical_reg;
// If it's not referencing the zero register, then mark the register
// as not ready.
if (arch_reg != floatZeroReg) {
// Get a free floating point register to rename to.
renamed_reg = freeList->getFloatReg();
// Update the floating point rename map.
floatRenameMap[arch_reg].physical_reg = renamed_reg;
assert(renamed_reg < numPhysicalRegs &&
renamed_reg >= numPhysicalIntRegs);
// Mark register as not ready.
floatScoreboard[renamed_reg] = false;
} else {
// Otherwise return the zero register so nothing bad happens.
renamed_reg = floatZeroReg;
}
} else {
// Subtract off the base offset for miscellaneous registers.
arch_reg = arch_reg - numLogicalRegs;
// No renaming happens to the misc. registers. They are simply the
// registers that come after all the physical registers; thus
// take the base architected register and add the physical registers
// to it.
renamed_reg = arch_reg + numPhysicalRegs;
// Set the previous register to the same register; mainly it must be
// known that the prev reg was outside the range of normal registers
// so the free list can avoid adding it.
prev_reg = renamed_reg;
assert(renamed_reg < numPhysicalRegs + numMiscRegs);
miscScoreboard[renamed_reg] = false;
}
return RenameInfo(renamed_reg, prev_reg);
}
//Perhaps give this a pair as a return value, of the physical register
//and whether or not it's ready.
PhysRegIndex
SimpleRenameMap::lookup(RegIndex arch_reg)
{
if (arch_reg < numLogicalIntRegs) {
return intRenameMap[arch_reg].physical_reg;
} else if (arch_reg < numLogicalRegs) {
// Subtract off the base FP offset.
// arch_reg = arch_reg - numLogicalIntRegs;
return floatRenameMap[arch_reg].physical_reg;
} else {
// Subtract off the misc registers offset.
arch_reg = arch_reg - numLogicalRegs;
// Misc. regs don't rename, so simply add the base arch reg to
// the number of physical registers.
return numPhysicalRegs + arch_reg;
}
}
bool
SimpleRenameMap::isReady(PhysRegIndex phys_reg)
{
if (phys_reg < numPhysicalIntRegs) {
return intScoreboard[phys_reg];
} else if (phys_reg < numPhysicalRegs) {
// Subtract off the base FP offset.
// phys_reg = phys_reg - numPhysicalIntRegs;
return floatScoreboard[phys_reg];
} else {
// Subtract off the misc registers offset.
// phys_reg = phys_reg - numPhysicalRegs;
return miscScoreboard[phys_reg];
}
}
// In this implementation the miscellaneous registers do not actually rename,
// so this function does not allow you to try to change their mappings.
void
SimpleRenameMap::setEntry(RegIndex arch_reg, PhysRegIndex renamed_reg)
{
if (arch_reg < numLogicalIntRegs) {
DPRINTF(Rename, "Rename Map: Integer register %i being set to %i.\n",
(int)arch_reg, renamed_reg);
intRenameMap[arch_reg].physical_reg = renamed_reg;
} else {
assert(arch_reg < (numLogicalIntRegs + numLogicalFloatRegs));
DPRINTF(Rename, "Rename Map: Float register %i being set to %i.\n",
(int)arch_reg - numLogicalIntRegs, renamed_reg);
floatRenameMap[arch_reg].physical_reg = renamed_reg;
}
}
void
SimpleRenameMap::squash(vector<RegIndex> freed_regs,
vector<UnmapInfo> unmaps)
{
panic("Not sure this function should be called.");
// Not sure the rename map should be able to access the free list
// like this.
while (!freed_regs.empty()) {
RegIndex free_register = freed_regs.back();
if (free_register < numPhysicalIntRegs) {
freeList->addIntReg(free_register);
} else {
// Subtract off the base FP dependence tag.
free_register = free_register - numPhysicalIntRegs;
freeList->addFloatReg(free_register);
}
freed_regs.pop_back();
}
// Take unmap info and roll back the rename map.
}
void
SimpleRenameMap::markAsReady(PhysRegIndex ready_reg)
{
DPRINTF(Rename, "Rename map: Marking register %i as ready.\n",
(int)ready_reg);
if (ready_reg < numPhysicalIntRegs) {
assert(ready_reg >= 0);
intScoreboard[ready_reg] = 1;
} else if (ready_reg < numPhysicalRegs) {
// Subtract off the base FP offset.
// ready_reg = ready_reg - numPhysicalIntRegs;
floatScoreboard[ready_reg] = 1;
} else {
//Subtract off the misc registers offset.
// ready_reg = ready_reg - numPhysicalRegs;
miscScoreboard[ready_reg] = 1;
}
}
int
SimpleRenameMap::numFreeEntries()
{
int free_int_regs = freeList->numFreeIntRegs();
int free_float_regs = freeList->numFreeFloatRegs();
if (free_int_regs < free_float_regs) {
return free_int_regs;
} else {
return free_float_regs;
}
}
|