1/*
2 * Copyright (c) 2003-2005 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
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: Steve Reinhardt
29 */
30
31#ifndef __CPU_STATIC_INST_HH__
32#define __CPU_STATIC_INST_HH__
33
34#include <bitset>
35#include <string>
36
37#include "arch/isa_traits.hh"
38#include "sim/faults.hh"
39#include "base/bitfield.hh"
40#include "base/hashmap.hh"
41#include "base/misc.hh"
42#include "base/refcnt.hh"
43#include "cpu/op_class.hh"
44#include "cpu/o3/dyn_inst.hh"
45#include "sim/faults.hh"
46#include "sim/host.hh"
47
48// forward declarations
49struct AlphaSimpleImpl;
50struct OzoneImpl;
51struct SimpleImpl;
52class ThreadContext;
53class DynInst;
54class Packet;
55
56template <class Impl>
57class OzoneDynInst;
58
59class CheckerCPU;
60class FastCPU;
61class AtomicSimpleCPU;
62class TimingSimpleCPU;
63class InorderCPU;
64class SymbolTable;
65
66namespace Trace {
67 class InstRecord;
68}
69
70typedef uint32_t MicroPC;
71
72/**
73 * Base, ISA-independent static instruction class.
74 *
75 * The main component of this class is the vector of flags and the
76 * associated methods for reading them. Any object that can rely
77 * solely on these flags can process instructions without being
78 * recompiled for multiple ISAs.
79 */
80class StaticInstBase : public RefCounted
81{
82 protected:
83
84 /// Set of boolean static instruction properties.
85 ///
86 /// Notes:
87 /// - The IsInteger and IsFloating flags are based on the class of
88 /// registers accessed by the instruction. Although most
89 /// instructions will have exactly one of these two flags set, it
90 /// is possible for an instruction to have neither (e.g., direct
91 /// unconditional branches, memory barriers) or both (e.g., an
92 /// FP/int conversion).
93 /// - If IsMemRef is set, then exactly one of IsLoad or IsStore
94 /// will be set.
95 /// - If IsControl is set, then exactly one of IsDirectControl or
96 /// IsIndirect Control will be set, and exactly one of
97 /// IsCondControl or IsUncondControl will be set.
98 /// - IsSerializing, IsMemBarrier, and IsWriteBarrier are
99 /// implemented as flags since in the current model there's no
100 /// other way for instructions to inject behavior into the
101 /// pipeline outside of fetch. Once we go to an exec-in-exec CPU
102 /// model we should be able to get rid of these flags and
103 /// implement this behavior via the execute() methods.
104 ///
105 enum Flags {
106 IsNop, ///< Is a no-op (no effect at all).
107
108 IsInteger, ///< References integer regs.
109 IsFloating, ///< References FP regs.
110
111 IsMemRef, ///< References memory (load, store, or prefetch).
112 IsLoad, ///< Reads from memory (load or prefetch).
113 IsStore, ///< Writes to memory.
114 IsStoreConditional, ///< Store conditional instruction.
115 IsInstPrefetch, ///< Instruction-cache prefetch.
116 IsDataPrefetch, ///< Data-cache prefetch.
117 IsCopy, ///< Fast Cache block copy
118
119 IsControl, ///< Control transfer instruction.
120 IsDirectControl, ///< PC relative control transfer.
121 IsIndirectControl, ///< Register indirect control transfer.
122 IsCondControl, ///< Conditional control transfer.
123 IsUncondControl, ///< Unconditional control transfer.
124 IsCall, ///< Subroutine call.
125 IsReturn, ///< Subroutine return.
126
127 IsCondDelaySlot,///< Conditional Delay-Slot Instruction
128
129 IsThreadSync, ///< Thread synchronization operation.
130
131 IsSerializing, ///< Serializes pipeline: won't execute until all
132 /// older instructions have committed.
133 IsSerializeBefore,
134 IsSerializeAfter,
135 IsMemBarrier, ///< Is a memory barrier
136 IsWriteBarrier, ///< Is a write barrier
137
138 IsNonSpeculative, ///< Should not be executed speculatively
139 IsQuiesce, ///< Is a quiesce instruction
140
141 IsIprAccess, ///< Accesses IPRs
142 IsUnverifiable, ///< Can't be verified by a checker
143
144 //Flags for microcode
145 IsMacroOp, ///< Is a macroop containing microops
146 IsMicroOp, ///< Is a microop
147 IsDelayedCommit, ///< This microop doesn't commit right away
148 IsLastMicroOp, ///< This microop ends a microop sequence
149 //This flag doesn't do anything yet
150 IsMicroBranch, ///< This microop branches within the microcode for a macroop
151
152 NumFlags
153 };
154
155 /// Flag values for this instruction.
156 std::bitset<NumFlags> flags;
157
158 /// See opClass().
159 OpClass _opClass;
160
161 /// See numSrcRegs().
162 int8_t _numSrcRegs;
163
164 /// See numDestRegs().
165 int8_t _numDestRegs;
166
167 /// The following are used to track physical register usage
168 /// for machines with separate int & FP reg files.
169 //@{
170 int8_t _numFPDestRegs;
171 int8_t _numIntDestRegs;
172 //@}
173
174 /// Constructor.
175 /// It's important to initialize everything here to a sane
176 /// default, since the decoder generally only overrides
177 /// the fields that are meaningful for the particular
178 /// instruction.
179 StaticInstBase(OpClass __opClass)
180 : _opClass(__opClass), _numSrcRegs(0), _numDestRegs(0),
181 _numFPDestRegs(0), _numIntDestRegs(0)
182 {
183 }
184
185 public:
186
187 /// @name Register information.
188 /// The sum of numFPDestRegs() and numIntDestRegs() equals
189 /// numDestRegs(). The former two functions are used to track
190 /// physical register usage for machines with separate int & FP
191 /// reg files.
192 //@{
193 /// Number of source registers.
194 int8_t numSrcRegs() const { return _numSrcRegs; }
195 /// Number of destination registers.
196 int8_t numDestRegs() const { return _numDestRegs; }
197 /// Number of floating-point destination regs.
198 int8_t numFPDestRegs() const { return _numFPDestRegs; }
199 /// Number of integer destination regs.
200 int8_t numIntDestRegs() const { return _numIntDestRegs; }
201 //@}
202
203 /// @name Flag accessors.
204 /// These functions are used to access the values of the various
205 /// instruction property flags. See StaticInstBase::Flags for descriptions
206 /// of the individual flags.
207 //@{
208
209 bool isNop() const { return flags[IsNop]; }
210
211 bool isMemRef() const { return flags[IsMemRef]; }
212 bool isLoad() const { return flags[IsLoad]; }
213 bool isStore() const { return flags[IsStore]; }
214 bool isStoreConditional() const { return flags[IsStoreConditional]; }
215 bool isInstPrefetch() const { return flags[IsInstPrefetch]; }
216 bool isDataPrefetch() const { return flags[IsDataPrefetch]; }
217 bool isCopy() const { return flags[IsCopy];}
218
219 bool isInteger() const { return flags[IsInteger]; }
220 bool isFloating() const { return flags[IsFloating]; }
221
222 bool isControl() const { return flags[IsControl]; }
223 bool isCall() const { return flags[IsCall]; }
224 bool isReturn() const { return flags[IsReturn]; }
225 bool isDirectCtrl() const { return flags[IsDirectControl]; }
226 bool isIndirectCtrl() const { return flags[IsIndirectControl]; }
227 bool isCondCtrl() const { return flags[IsCondControl]; }
228 bool isUncondCtrl() const { return flags[IsUncondControl]; }
229 bool isCondDelaySlot() const { return flags[IsCondDelaySlot]; }
230
231 bool isThreadSync() const { return flags[IsThreadSync]; }
232 bool isSerializing() const { return flags[IsSerializing] ||
233 flags[IsSerializeBefore] ||
234 flags[IsSerializeAfter]; }
235 bool isSerializeBefore() const { return flags[IsSerializeBefore]; }
236 bool isSerializeAfter() const { return flags[IsSerializeAfter]; }
237 bool isMemBarrier() const { return flags[IsMemBarrier]; }
238 bool isWriteBarrier() const { return flags[IsWriteBarrier]; }
239 bool isNonSpeculative() const { return flags[IsNonSpeculative]; }
240 bool isQuiesce() const { return flags[IsQuiesce]; }
241 bool isIprAccess() const { return flags[IsIprAccess]; }
242 bool isUnverifiable() const { return flags[IsUnverifiable]; }
243 bool isMacroOp() const { return flags[IsMacroOp]; }
244 bool isMicroOp() const { return flags[IsMicroOp]; }
245 bool isDelayedCommit() const { return flags[IsDelayedCommit]; }
246 bool isLastMicroOp() const { return flags[IsLastMicroOp]; }
247 //This flag doesn't do anything yet
248 bool isMicroBranch() const { return flags[IsMicroBranch]; }
249 //@}
250
251 /// Operation class. Used to select appropriate function unit in issue.
252 OpClass opClass() const { return _opClass; }
253};
254
255
256// forward declaration
257class StaticInstPtr;
258
259/**
260 * Generic yet ISA-dependent static instruction class.
261 *
262 * This class builds on StaticInstBase, defining fields and interfaces
263 * that are generic across all ISAs but that differ in details
264 * according to the specific ISA being used.
265 */
266class StaticInst : public StaticInstBase
267{
268 public:
269
270 /// Binary machine instruction type.
271 typedef TheISA::MachInst MachInst;
272 /// Binary extended machine instruction type.
273 typedef TheISA::ExtMachInst ExtMachInst;
274 /// Logical register index type.
275 typedef TheISA::RegIndex RegIndex;
276
277 enum {
278 MaxInstSrcRegs = TheISA::MaxInstSrcRegs, //< Max source regs
279 MaxInstDestRegs = TheISA::MaxInstDestRegs, //< Max dest regs
280 };
281
282
283 /// Return logical index (architectural reg num) of i'th destination reg.
284 /// Only the entries from 0 through numDestRegs()-1 are valid.
285 RegIndex destRegIdx(int i) const { return _destRegIdx[i]; }
286
287 /// Return logical index (architectural reg num) of i'th source reg.
288 /// Only the entries from 0 through numSrcRegs()-1 are valid.
289 RegIndex srcRegIdx(int i) const { return _srcRegIdx[i]; }
290
291 /// Pointer to a statically allocated "null" instruction object.
292 /// Used to give eaCompInst() and memAccInst() something to return
293 /// when called on non-memory instructions.
294 static StaticInstPtr nullStaticInstPtr;
295
296 /**
297 * Memory references only: returns "fake" instruction representing
298 * the effective address part of the memory operation. Used to
299 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for
300 * just the EA computation.
301 */
302 virtual const
303 StaticInstPtr &eaCompInst() const { return nullStaticInstPtr; }
304
305 /**
306 * Memory references only: returns "fake" instruction representing
307 * the memory access part of the memory operation. Used to
308 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for
309 * just the memory access (not the EA computation).
310 */
311 virtual const
312 StaticInstPtr &memAccInst() const { return nullStaticInstPtr; }
313
314 /// The binary machine instruction.
315 const ExtMachInst machInst;
316
317 protected:
318
319 /// See destRegIdx().
320 RegIndex _destRegIdx[MaxInstDestRegs];
321 /// See srcRegIdx().
322 RegIndex _srcRegIdx[MaxInstSrcRegs];
323
324 /**
325 * Base mnemonic (e.g., "add"). Used by generateDisassembly()
326 * methods. Also useful to readily identify instructions from
327 * within the debugger when #cachedDisassembly has not been
328 * initialized.
329 */
330 const char *mnemonic;
331
332 /**
333 * String representation of disassembly (lazily evaluated via
334 * disassemble()).
335 */
336 mutable std::string *cachedDisassembly;
337
338 /**
339 * Internal function to generate disassembly string.
340 */
341 virtual std::string
342 generateDisassembly(Addr pc, const SymbolTable *symtab) const = 0;
343
344 /// Constructor.
345 StaticInst(const char *_mnemonic, ExtMachInst _machInst, OpClass __opClass)
346 : StaticInstBase(__opClass),
347 machInst(_machInst), mnemonic(_mnemonic), cachedDisassembly(0)
348 {
349 }
350
351 public:
352
353 virtual ~StaticInst()
354 {
355 if (cachedDisassembly)
356 delete cachedDisassembly;
357 }
358
359/**
360 * The execute() signatures are auto-generated by scons based on the
361 * set of CPU models we are compiling in today.
362 */
363#include "cpu/static_inst_exec_sigs.hh"
364
365 /**
366 * Return the microop that goes with a particular micropc. This should
367 * only be defined/used in macroops which will contain microops
368 */
369 virtual StaticInstPtr fetchMicroOp(MicroPC micropc);
370
371 /**
372 * Return the target address for a PC-relative branch.
373 * Invalid if not a PC-relative branch (i.e. isDirectCtrl()
374 * should be true).
375 */
376 virtual Addr branchTarget(Addr branchPC) const
377 {
378 panic("StaticInst::branchTarget() called on instruction "
379 "that is not a PC-relative branch.");
380 }
381
382 /**
383 * Return the target address for an indirect branch (jump). The
384 * register value is read from the supplied thread context, so
385 * the result is valid only if the thread context is about to
386 * execute the branch in question. Invalid if not an indirect
387 * branch (i.e. isIndirectCtrl() should be true).
388 */
389 virtual Addr branchTarget(ThreadContext *tc) const
390 {
391 panic("StaticInst::branchTarget() called on instruction "
392 "that is not an indirect branch.");
393 }
394
395 /**
396 * Return true if the instruction is a control transfer, and if so,
397 * return the target address as well.
398 */
399 bool hasBranchTarget(Addr pc, ThreadContext *tc, Addr &tgt) const;
400
401 /**
402 * Return string representation of disassembled instruction.
403 * The default version of this function will call the internal
404 * virtual generateDisassembly() function to get the string,
405 * then cache it in #cachedDisassembly. If the disassembly
406 * should not be cached, this function should be overridden directly.
407 */
408 virtual const std::string &disassemble(Addr pc,
409 const SymbolTable *symtab = 0) const
410 {
411 if (!cachedDisassembly)
412 cachedDisassembly =
413 new std::string(generateDisassembly(pc, symtab));
414
415 return *cachedDisassembly;
416 }
417
418 /// Decoded instruction cache type.
419 /// For now we're using a generic hash_map; this seems to work
420 /// pretty well.
421 typedef m5::hash_map<ExtMachInst, StaticInstPtr> DecodeCache;
422
423 /// A cache of decoded instruction objects.
424 static DecodeCache decodeCache;
425
426 /**
427 * Dump some basic stats on the decode cache hash map.
428 * Only gets called if DECODE_CACHE_HASH_STATS is defined.
429 */
430 static void dumpDecodeCacheStats();
431
432 /// Decode a machine instruction.
433 /// @param mach_inst The binary instruction to decode.
434 /// @retval A pointer to the corresponding StaticInst object.
435 //This is defined as inline below.
436 static StaticInstPtr decode(ExtMachInst mach_inst);
437
438 /// Return opcode of machine instruction
439 uint32_t getOpcode() { return bits(machInst, 31, 26);}
440
441 /// Return name of machine instruction
442 std::string getName() { return mnemonic; }
443};
444
445typedef RefCountingPtr<StaticInstBase> StaticInstBasePtr;
446
447/// Reference-counted pointer to a StaticInst object.
448/// This type should be used instead of "StaticInst *" so that
449/// StaticInst objects can be properly reference-counted.
450class StaticInstPtr : public RefCountingPtr<StaticInst>
451{
452 public:
453 /// Constructor.
454 StaticInstPtr()
455 : RefCountingPtr<StaticInst>()
456 {
457 }
458
459 /// Conversion from "StaticInst *".
460 StaticInstPtr(StaticInst *p)
461 : RefCountingPtr<StaticInst>(p)
462 {
463 }
464
465 /// Copy constructor.
466 StaticInstPtr(const StaticInstPtr &r)
467 : RefCountingPtr<StaticInst>(r)
468 {
469 }
470
471 /// Construct directly from machine instruction.
472 /// Calls StaticInst::decode().
473 StaticInstPtr(TheISA::ExtMachInst mach_inst)
474 : RefCountingPtr<StaticInst>(StaticInst::decode(mach_inst))
475 {
476 }
477
478 /// Convert to pointer to StaticInstBase class.
479 operator const StaticInstBasePtr()
480 {
481 return this->get();
482 }
483};
484
485inline StaticInstPtr
486StaticInst::decode(StaticInst::ExtMachInst mach_inst)
487{
488#ifdef DECODE_CACHE_HASH_STATS
489 // Simple stats on decode hash_map. Turns out the default
490 // hash function is as good as anything I could come up with.
491 const int dump_every_n = 10000000;
492 static int decodes_til_dump = dump_every_n;
493
494 if (--decodes_til_dump == 0) {
495 dumpDecodeCacheStats();
496 decodes_til_dump = dump_every_n;
497 }
498#endif
499
500 DecodeCache::iterator iter = decodeCache.find(mach_inst);
501 if (iter != decodeCache.end()) {
502 return iter->second;
503 }
504
505 StaticInstPtr si = TheISA::decodeInst(mach_inst);
506 decodeCache[mach_inst] = si;
507 return si;
508}
509
510#endif // __CPU_STATIC_INST_HH__