2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
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.
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.
28 * Authors: Steve Reinhardt
31 #ifndef __CPU_STATIC_INST_HH__
32 #define __CPU_STATIC_INST_HH__
37 #include "arch/isa_traits.hh"
38 #include "arch/types.hh"
39 #include "arch/registers.hh"
40 #include "config/the_isa.hh"
41 #include "base/hashmap.hh"
42 #include "base/misc.hh"
43 #include "base/refcnt.hh"
44 #include "base/types.hh"
45 #include "cpu/op_class.hh"
46 #include "sim/fault.hh"
48 // forward declarations
49 struct AlphaSimpleImpl;
57 template <class Impl> class BaseO3DynInst;
58 typedef BaseO3DynInst<O3CPUImpl> O3DynInst;
59 template <class Impl> class OzoneDynInst;
64 class AtomicSimpleCPU;
65 class TimingSimpleCPU;
75 * Base, ISA-independent static instruction class.
77 * The main component of this class is the vector of flags and the
78 * associated methods for reading them. Any object that can rely
79 * solely on these flags can process instructions without being
80 * recompiled for multiple ISAs.
82 class StaticInstBase : public RefCounted
86 /// Set of boolean static instruction properties.
89 /// - The IsInteger and IsFloating flags are based on the class of
90 /// registers accessed by the instruction. Although most
91 /// instructions will have exactly one of these two flags set, it
92 /// is possible for an instruction to have neither (e.g., direct
93 /// unconditional branches, memory barriers) or both (e.g., an
94 /// FP/int conversion).
95 /// - If IsMemRef is set, then exactly one of IsLoad or IsStore
97 /// - If IsControl is set, then exactly one of IsDirectControl or
98 /// IsIndirect Control will be set, and exactly one of
99 /// IsCondControl or IsUncondControl will be set.
100 /// - IsSerializing, IsMemBarrier, and IsWriteBarrier are
101 /// implemented as flags since in the current model there's no
102 /// other way for instructions to inject behavior into the
103 /// pipeline outside of fetch. Once we go to an exec-in-exec CPU
104 /// model we should be able to get rid of these flags and
105 /// implement this behavior via the execute() methods.
108 IsNop, ///< Is a no-op (no effect at all).
110 IsInteger, ///< References integer regs.
111 IsFloating, ///< References FP regs.
113 IsMemRef, ///< References memory (load, store, or prefetch).
114 IsLoad, ///< Reads from memory (load or prefetch).
115 IsStore, ///< Writes to memory.
116 IsStoreConditional, ///< Store conditional instruction.
117 IsIndexed, ///< Accesses memory with an indexed address computation
118 IsInstPrefetch, ///< Instruction-cache prefetch.
119 IsDataPrefetch, ///< Data-cache prefetch.
120 IsCopy, ///< Fast Cache block copy
122 IsControl, ///< Control transfer instruction.
123 IsDirectControl, ///< PC relative control transfer.
124 IsIndirectControl, ///< Register indirect control transfer.
125 IsCondControl, ///< Conditional control transfer.
126 IsUncondControl, ///< Unconditional control transfer.
127 IsCall, ///< Subroutine call.
128 IsReturn, ///< Subroutine return.
130 IsCondDelaySlot,///< Conditional Delay-Slot Instruction
132 IsThreadSync, ///< Thread synchronization operation.
134 IsSerializing, ///< Serializes pipeline: won't execute until all
135 /// older instructions have committed.
138 IsMemBarrier, ///< Is a memory barrier
139 IsWriteBarrier, ///< Is a write barrier
140 IsReadBarrier, ///< Is a read barrier
141 IsERET, /// <- Causes the IFU to stall (MIPS ISA)
143 IsNonSpeculative, ///< Should not be executed speculatively
144 IsQuiesce, ///< Is a quiesce instruction
146 IsIprAccess, ///< Accesses IPRs
147 IsUnverifiable, ///< Can't be verified by a checker
149 IsSyscall, ///< Causes a system call to be emulated in syscall
152 //Flags for microcode
153 IsMacroop, ///< Is a macroop containing microops
154 IsMicroop, ///< Is a microop
155 IsDelayedCommit, ///< This microop doesn't commit right away
156 IsLastMicroop, ///< This microop ends a microop sequence
157 IsFirstMicroop, ///< This microop begins a microop sequence
158 //This flag doesn't do anything yet
159 IsMicroBranch, ///< This microop branches within the microcode for a macroop
161 IsSquashAfter, ///< Squash all uncommitted state after executed
167 /// Flag values for this instruction.
168 std::bitset<NumFlags> flags;
173 /// See numSrcRegs().
176 /// See numDestRegs().
179 /// The following are used to track physical register usage
180 /// for machines with separate int & FP reg files.
182 int8_t _numFPDestRegs;
183 int8_t _numIntDestRegs;
187 /// It's important to initialize everything here to a sane
188 /// default, since the decoder generally only overrides
189 /// the fields that are meaningful for the particular
191 StaticInstBase(OpClass __opClass)
192 : _opClass(__opClass), _numSrcRegs(0), _numDestRegs(0),
193 _numFPDestRegs(0), _numIntDestRegs(0)
199 /// @name Register information.
200 /// The sum of numFPDestRegs() and numIntDestRegs() equals
201 /// numDestRegs(). The former two functions are used to track
202 /// physical register usage for machines with separate int & FP
205 /// Number of source registers.
206 int8_t numSrcRegs() const { return _numSrcRegs; }
207 /// Number of destination registers.
208 int8_t numDestRegs() const { return _numDestRegs; }
209 /// Number of floating-point destination regs.
210 int8_t numFPDestRegs() const { return _numFPDestRegs; }
211 /// Number of integer destination regs.
212 int8_t numIntDestRegs() const { return _numIntDestRegs; }
215 /// @name Flag accessors.
216 /// These functions are used to access the values of the various
217 /// instruction property flags. See StaticInstBase::Flags for descriptions
218 /// of the individual flags.
221 bool isNop() const { return flags[IsNop]; }
223 bool isMemRef() const { return flags[IsMemRef]; }
224 bool isLoad() const { return flags[IsLoad]; }
225 bool isStore() const { return flags[IsStore]; }
226 bool isStoreConditional() const { return flags[IsStoreConditional]; }
227 bool isInstPrefetch() const { return flags[IsInstPrefetch]; }
228 bool isDataPrefetch() const { return flags[IsDataPrefetch]; }
229 bool isPrefetch() const { return isInstPrefetch() ||
231 bool isCopy() const { return flags[IsCopy];}
233 bool isInteger() const { return flags[IsInteger]; }
234 bool isFloating() const { return flags[IsFloating]; }
236 bool isControl() const { return flags[IsControl]; }
237 bool isCall() const { return flags[IsCall]; }
238 bool isReturn() const { return flags[IsReturn]; }
239 bool isDirectCtrl() const { return flags[IsDirectControl]; }
240 bool isIndirectCtrl() const { return flags[IsIndirectControl]; }
241 bool isCondCtrl() const { return flags[IsCondControl]; }
242 bool isUncondCtrl() const { return flags[IsUncondControl]; }
243 bool isCondDelaySlot() const { return flags[IsCondDelaySlot]; }
245 bool isThreadSync() const { return flags[IsThreadSync]; }
246 bool isSerializing() const { return flags[IsSerializing] ||
247 flags[IsSerializeBefore] ||
248 flags[IsSerializeAfter]; }
249 bool isSerializeBefore() const { return flags[IsSerializeBefore]; }
250 bool isSerializeAfter() const { return flags[IsSerializeAfter]; }
251 bool isSquashAfter() const { return flags[IsSquashAfter]; }
252 bool isMemBarrier() const { return flags[IsMemBarrier]; }
253 bool isWriteBarrier() const { return flags[IsWriteBarrier]; }
254 bool isNonSpeculative() const { return flags[IsNonSpeculative]; }
255 bool isQuiesce() const { return flags[IsQuiesce]; }
256 bool isIprAccess() const { return flags[IsIprAccess]; }
257 bool isUnverifiable() const { return flags[IsUnverifiable]; }
258 bool isSyscall() const { return flags[IsSyscall]; }
259 bool isMacroop() const { return flags[IsMacroop]; }
260 bool isMicroop() const { return flags[IsMicroop]; }
261 bool isDelayedCommit() const { return flags[IsDelayedCommit]; }
262 bool isLastMicroop() const { return flags[IsLastMicroop]; }
263 bool isFirstMicroop() const { return flags[IsFirstMicroop]; }
264 //This flag doesn't do anything yet
265 bool isMicroBranch() const { return flags[IsMicroBranch]; }
268 void setLastMicroop() { flags[IsLastMicroop] = true; }
269 void setDelayedCommit() { flags[IsDelayedCommit] = true; }
271 /// Operation class. Used to select appropriate function unit in issue.
272 OpClass opClass() const { return _opClass; }
276 // forward declaration
280 * Generic yet ISA-dependent static instruction class.
282 * This class builds on StaticInstBase, defining fields and interfaces
283 * that are generic across all ISAs but that differ in details
284 * according to the specific ISA being used.
286 class StaticInst : public StaticInstBase
290 /// Binary machine instruction type.
291 typedef TheISA::MachInst MachInst;
292 /// Binary extended machine instruction type.
293 typedef TheISA::ExtMachInst ExtMachInst;
294 /// Logical register index type.
295 typedef TheISA::RegIndex RegIndex;
298 MaxInstSrcRegs = TheISA::MaxInstSrcRegs, //< Max source regs
299 MaxInstDestRegs = TheISA::MaxInstDestRegs, //< Max dest regs
303 /// Return logical index (architectural reg num) of i'th destination reg.
304 /// Only the entries from 0 through numDestRegs()-1 are valid.
305 RegIndex destRegIdx(int i) const { return _destRegIdx[i]; }
307 /// Return logical index (architectural reg num) of i'th source reg.
308 /// Only the entries from 0 through numSrcRegs()-1 are valid.
309 RegIndex srcRegIdx(int i) const { return _srcRegIdx[i]; }
311 /// Pointer to a statically allocated "null" instruction object.
312 /// Used to give eaCompInst() and memAccInst() something to return
313 /// when called on non-memory instructions.
314 static StaticInstPtr nullStaticInstPtr;
317 * Memory references only: returns "fake" instruction representing
318 * the effective address part of the memory operation. Used to
319 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for
320 * just the EA computation.
323 StaticInstPtr &eaCompInst() const { return nullStaticInstPtr; }
326 * Memory references only: returns "fake" instruction representing
327 * the memory access part of the memory operation. Used to
328 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for
329 * just the memory access (not the EA computation).
332 StaticInstPtr &memAccInst() const { return nullStaticInstPtr; }
334 /// The binary machine instruction.
335 const ExtMachInst machInst;
339 /// See destRegIdx().
340 RegIndex _destRegIdx[MaxInstDestRegs];
342 RegIndex _srcRegIdx[MaxInstSrcRegs];
345 * Base mnemonic (e.g., "add"). Used by generateDisassembly()
346 * methods. Also useful to readily identify instructions from
347 * within the debugger when #cachedDisassembly has not been
350 const char *mnemonic;
353 * String representation of disassembly (lazily evaluated via
356 mutable std::string *cachedDisassembly;
359 * Internal function to generate disassembly string.
362 generateDisassembly(Addr pc, const SymbolTable *symtab) const = 0;
365 StaticInst(const char *_mnemonic, ExtMachInst _machInst, OpClass __opClass)
366 : StaticInstBase(__opClass),
367 machInst(_machInst), mnemonic(_mnemonic), cachedDisassembly(0)
371 virtual ~StaticInst();
374 * The execute() signatures are auto-generated by scons based on the
375 * set of CPU models we are compiling in today.
377 #include "cpu/static_inst_exec_sigs.hh"
379 virtual void advancePC(TheISA::PCState &pcState) const = 0;
382 * Return the microop that goes with a particular micropc. This should
383 * only be defined/used in macroops which will contain microops
385 virtual StaticInstPtr fetchMicroop(MicroPC upc) const;
388 * Return the target address for a PC-relative branch.
389 * Invalid if not a PC-relative branch (i.e. isDirectCtrl()
392 virtual TheISA::PCState branchTarget(const TheISA::PCState &pc) const;
395 * Return the target address for an indirect branch (jump). The
396 * register value is read from the supplied thread context, so
397 * the result is valid only if the thread context is about to
398 * execute the branch in question. Invalid if not an indirect
399 * branch (i.e. isIndirectCtrl() should be true).
401 virtual TheISA::PCState branchTarget(ThreadContext *tc) const;
404 * Return true if the instruction is a control transfer, and if so,
405 * return the target address as well.
407 bool hasBranchTarget(const TheISA::PCState &pc, ThreadContext *tc,
408 TheISA::PCState &tgt) const;
411 * Return string representation of disassembled instruction.
412 * The default version of this function will call the internal
413 * virtual generateDisassembly() function to get the string,
414 * then cache it in #cachedDisassembly. If the disassembly
415 * should not be cached, this function should be overridden directly.
417 virtual const std::string &disassemble(Addr pc,
418 const SymbolTable *symtab = 0) const;
420 /// Decoded instruction cache type.
421 /// For now we're using a generic hash_map; this seems to work
423 typedef m5::hash_map<ExtMachInst, StaticInstPtr> DecodeCache;
425 /// A cache of decoded instruction objects.
426 static DecodeCache decodeCache;
429 * Dump some basic stats on the decode cache hash map.
430 * Only gets called if DECODE_CACHE_HASH_STATS is defined.
432 static void dumpDecodeCacheStats();
434 /// Decode a machine instruction.
435 /// @param mach_inst The binary instruction to decode.
436 /// @retval A pointer to the corresponding StaticInst object.
437 //This is defined as inlined below.
438 static StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
440 /// Return name of machine instruction
441 std::string getName() { return mnemonic; }
443 /// Decoded instruction cache type, for address decoding.
444 /// A generic hash_map is used.
445 typedef m5::hash_map<Addr, AddrDecodePage *> AddrDecodeCache;
447 /// A cache of decoded instruction objects from addresses.
448 static AddrDecodeCache addrDecodeCache;
453 AddrDecodePage *decodePage;
455 cacheElement() : decodePage(NULL) { }
458 /// An array of recently decoded instructions.
459 // might not use an array if there is only two elements
460 static struct cacheElement recentDecodes[2];
462 /// Updates the recently decoded instructions entries
463 /// @param page_addr The page address recently used.
464 /// @param decodePage Pointer to decoding page containing the decoded
467 updateCache(Addr page_addr, AddrDecodePage *decodePage)
469 recentDecodes[1].page_addr = recentDecodes[0].page_addr;
470 recentDecodes[1].decodePage = recentDecodes[0].decodePage;
471 recentDecodes[0].page_addr = page_addr;
472 recentDecodes[0].decodePage = decodePage;
475 /// Searches the decoded instruction cache for instruction decoding.
476 /// If it is not found, then we decode the instruction.
477 /// Otherwise, we get the instruction from the cache and move it into
478 /// the address-to-instruction decoding page.
479 /// @param mach_inst The binary instruction to decode.
480 /// @param addr The address that contained the binary instruction.
481 /// @param decodePage Pointer to decoding page containing the instruction.
482 /// @retval A pointer to the corresponding StaticInst object.
483 //This is defined as inlined below.
484 static StaticInstPtr searchCache(ExtMachInst mach_inst, Addr addr,
485 AddrDecodePage *decodePage);
488 typedef RefCountingPtr<StaticInstBase> StaticInstBasePtr;
490 /// Reference-counted pointer to a StaticInst object.
491 /// This type should be used instead of "StaticInst *" so that
492 /// StaticInst objects can be properly reference-counted.
493 class StaticInstPtr : public RefCountingPtr<StaticInst>
498 : RefCountingPtr<StaticInst>()
502 /// Conversion from "StaticInst *".
503 StaticInstPtr(StaticInst *p)
504 : RefCountingPtr<StaticInst>(p)
508 /// Copy constructor.
509 StaticInstPtr(const StaticInstPtr &r)
510 : RefCountingPtr<StaticInst>(r)
514 /// Construct directly from machine instruction.
515 /// Calls StaticInst::decode().
516 explicit StaticInstPtr(TheISA::ExtMachInst mach_inst, Addr addr)
517 : RefCountingPtr<StaticInst>(StaticInst::decode(mach_inst, addr))
521 /// Convert to pointer to StaticInstBase class.
522 operator const StaticInstBasePtr()
528 /// A page of a list of decoded instructions from an address.
531 typedef TheISA::ExtMachInst ExtMachInst;
533 StaticInstPtr instructions[TheISA::PageBytes];
534 bool valid[TheISA::PageBytes];
541 lowerMask = TheISA::PageBytes - 1;
542 memset(valid, 0, TheISA::PageBytes);
545 /// Checks if the instruction is already decoded and the machine
546 /// instruction in the cache matches the current machine instruction
547 /// related to the address
548 /// @param mach_inst The binary instruction to check
549 /// @param addr The address containing the instruction
551 decoded(ExtMachInst mach_inst, Addr addr)
553 return (valid[addr & lowerMask] &&
554 (instructions[addr & lowerMask]->machInst == mach_inst));
557 /// Returns the instruction object. decoded should be called first
558 /// to check if the instruction is valid.
559 /// @param addr The address of the instruction.
560 /// @retval A pointer to the corresponding StaticInst object.
564 return instructions[addr & lowerMask];
567 /// Inserts a pointer to a StaticInst object into the list of decoded
568 /// instructions on the page.
569 /// @param addr The address of the instruction.
570 /// @param si A pointer to the corresponding StaticInst object.
572 insert(Addr addr, StaticInstPtr &si)
574 instructions[addr & lowerMask] = si;
575 valid[addr & lowerMask] = true;
581 StaticInst::decode(StaticInst::ExtMachInst mach_inst, Addr addr)
583 #ifdef DECODE_CACHE_HASH_STATS
584 // Simple stats on decode hash_map. Turns out the default
585 // hash function is as good as anything I could come up with.
586 const int dump_every_n = 10000000;
587 static int decodes_til_dump = dump_every_n;
589 if (--decodes_til_dump == 0) {
590 dumpDecodeCacheStats();
591 decodes_til_dump = dump_every_n;
595 Addr page_addr = addr & ~(TheISA::PageBytes - 1);
597 // checks recently decoded addresses
598 if (recentDecodes[0].decodePage &&
599 page_addr == recentDecodes[0].page_addr) {
600 if (recentDecodes[0].decodePage->decoded(mach_inst, addr))
601 return recentDecodes[0].decodePage->getInst(addr);
603 return searchCache(mach_inst, addr, recentDecodes[0].decodePage);
606 if (recentDecodes[1].decodePage &&
607 page_addr == recentDecodes[1].page_addr) {
608 if (recentDecodes[1].decodePage->decoded(mach_inst, addr))
609 return recentDecodes[1].decodePage->getInst(addr);
611 return searchCache(mach_inst, addr, recentDecodes[1].decodePage);
614 // searches the page containing the address to decode
615 AddrDecodeCache::iterator iter = addrDecodeCache.find(page_addr);
616 if (iter != addrDecodeCache.end()) {
617 updateCache(page_addr, iter->second);
618 if (iter->second->decoded(mach_inst, addr))
619 return iter->second->getInst(addr);
621 return searchCache(mach_inst, addr, iter->second);
624 // creates a new object for a page of decoded instructions
625 AddrDecodePage *decodePage = new AddrDecodePage;
626 addrDecodeCache[page_addr] = decodePage;
627 updateCache(page_addr, decodePage);
628 return searchCache(mach_inst, addr, decodePage);
632 StaticInst::searchCache(ExtMachInst mach_inst, Addr addr,
633 AddrDecodePage *decodePage)
635 DecodeCache::iterator iter = decodeCache.find(mach_inst);
636 if (iter != decodeCache.end()) {
637 decodePage->insert(addr, iter->second);
641 StaticInstPtr si = TheISA::decodeInst(mach_inst);
642 decodePage->insert(addr, si);
643 decodeCache[mach_inst] = si;
647 #endif // __CPU_STATIC_INST_HH__