gem5/cpu/static_inst.hh
Steve Reinhardt 1d545281b9 Significant changes to ISA description to completely factor
out CPU model.  ISA description now generates multiple
output source files to (in theory) reduce compilation time.

arch/alpha/isa_desc:
    Update for parser changes.  Move most constructors
    out of class declarations (which are now in decoder.hh)
    and into decoder.cc.  Move all execute() methods into
    exec output.
arch/isa_parser.py:
    Significant changes to make ISA description completely
    independent of CPU model, and isolate model-dependent parts
    of parser into one little class (CpuModel).  Also split up code
    output into multiple files (a header, a main source file, and
    per-cpu execute() method files).

    Noticeable changes to language as a result.  See updated Doxygen
    documentation.
cpu/simple_cpu/simple_cpu.hh:
    SimpleCPUExecContext typedef no longer needed.
    Add forward declaration of Process.
cpu/static_inst.hh:
    SimpleCPUExecContext and FullCPUExecContext typedefs no longer needed.
    Make eaCompInst() and memAccInst() return const refs.

--HG--
extra : convert_revision : 71471f267804fafd0a881bac7445677e76334daf
2004-05-17 11:49:46 -07:00

448 lines
15 KiB
C++

/*
* Copyright (c) 2003 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __STATIC_INST_HH__
#define __STATIC_INST_HH__
#include <bitset>
#include <string>
#include "sim/host.hh"
#include "base/hashmap.hh"
#include "base/refcnt.hh"
#include "cpu/full_cpu/op_class.hh"
#include "targetarch/isa_traits.hh"
// forward declarations
class ExecContext;
class DynInst;
class SimpleCPU;
class SymbolTable;
namespace Trace {
class InstRecord;
}
/**
* Base, ISA-independent static instruction class.
*
* The main component of this class is the vector of flags and the
* associated methods for reading them. Any object that can rely
* solely on these flags can process instructions without being
* recompiled for multiple ISAs.
*/
class StaticInstBase : public RefCounted
{
protected:
/// Set of boolean static instruction properties.
///
/// Notes:
/// - The IsInteger and IsFloating flags are based on the class of
/// registers accessed by the instruction. Although most
/// instructions will have exactly one of these two flags set, it
/// is possible for an instruction to have neither (e.g., direct
/// unconditional branches, memory barriers) or both (e.g., an
/// FP/int conversion).
/// - If IsMemRef is set, then exactly one of IsLoad or IsStore
/// will be set. Prefetches are marked as IsLoad, even if they
/// prefetch exclusive copies.
/// - If IsControl is set, then exactly one of IsDirectControl or
/// IsIndirect Control will be set, and exactly one of
/// IsCondControl or IsUncondControl will be set.
/// - IsSerializing, IsMemBarrier, and IsWriteBarrier are
/// implemented as flags since in the current model there's no
/// other way for instructions to inject behavior into the
/// pipeline outside of fetch. Once we go to an exec-in-exec CPU
/// model we should be able to get rid of these flags and
/// implement this behavior via the execute() methods.
///
enum Flags {
IsNop, ///< Is a no-op (no effect at all).
IsInteger, ///< References integer regs.
IsFloating, ///< References FP regs.
IsMemRef, ///< References memory (load, store, or prefetch).
IsLoad, ///< Reads from memory (load or prefetch).
IsStore, ///< Writes to memory.
IsInstPrefetch, ///< Instruction-cache prefetch.
IsDataPrefetch, ///< Data-cache prefetch.
IsCopy, ///< Fast Cache block copy
IsControl, ///< Control transfer instruction.
IsDirectControl, ///< PC relative control transfer.
IsIndirectControl, ///< Register indirect control transfer.
IsCondControl, ///< Conditional control transfer.
IsUncondControl, ///< Unconditional control transfer.
IsCall, ///< Subroutine call.
IsReturn, ///< Subroutine return.
IsThreadSync, ///< Thread synchronization operation.
IsSerializing, ///< Serializes pipeline: won't until all
/// older instructions have committed.
IsMemBarrier, ///< Is a memory barrier
IsWriteBarrier, ///< Is a write barrier
NumFlags
};
/// Flag values for this instruction.
std::bitset<NumFlags> flags;
/// See opClass().
OpClass _opClass;
/// See numSrcRegs().
int8_t _numSrcRegs;
/// See numDestRegs().
int8_t _numDestRegs;
/// The following are used to track physical register usage
/// for machines with separate int & FP reg files.
//@{
int8_t _numFPDestRegs;
int8_t _numIntDestRegs;
//@}
/// Constructor.
/// It's important to initialize everything here to a sane
/// default, since the decoder generally only overrides
/// the fields that are meaningful for the particular
/// instruction.
StaticInstBase(OpClass __opClass)
: _opClass(__opClass), _numSrcRegs(0), _numDestRegs(0),
_numFPDestRegs(0), _numIntDestRegs(0)
{
}
public:
/// @name Register information.
/// The sum of numFPDestRegs() and numIntDestRegs() equals
/// numDestRegs(). The former two functions are used to track
/// physical register usage for machines with separate int & FP
/// reg files.
//@{
/// Number of source registers.
int8_t numSrcRegs() const { return _numSrcRegs; }
/// Number of destination registers.
int8_t numDestRegs() const { return _numDestRegs; }
/// Number of floating-point destination regs.
int8_t numFPDestRegs() const { return _numFPDestRegs; }
/// Number of integer destination regs.
int8_t numIntDestRegs() const { return _numIntDestRegs; }
//@}
/// @name Flag accessors.
/// These functions are used to access the values of the various
/// instruction property flags. See StaticInstBase::Flags for descriptions
/// of the individual flags.
//@{
bool isNop() const { return flags[IsNop]; }
bool isMemRef() const { return flags[IsMemRef]; }
bool isLoad() const { return flags[IsLoad]; }
bool isStore() const { return flags[IsStore]; }
bool isInstPrefetch() const { return flags[IsInstPrefetch]; }
bool isDataPrefetch() const { return flags[IsDataPrefetch]; }
bool isCopy() const { return flags[IsCopy];}
bool isInteger() const { return flags[IsInteger]; }
bool isFloating() const { return flags[IsFloating]; }
bool isControl() const { return flags[IsControl]; }
bool isCall() const { return flags[IsCall]; }
bool isReturn() const { return flags[IsReturn]; }
bool isDirectCtrl() const { return flags[IsDirectControl]; }
bool isIndirectCtrl() const { return flags[IsIndirectControl]; }
bool isCondCtrl() const { return flags[IsCondControl]; }
bool isUncondCtrl() const { return flags[IsUncondControl]; }
bool isThreadSync() const { return flags[IsThreadSync]; }
bool isSerializing() const { return flags[IsSerializing]; }
bool isMemBarrier() const { return flags[IsMemBarrier]; }
bool isWriteBarrier() const { return flags[IsWriteBarrier]; }
//@}
/// Operation class. Used to select appropriate function unit in issue.
OpClass opClass() const { return _opClass; }
};
// forward declaration
template <class ISA>
class StaticInstPtr;
/**
* Generic yet ISA-dependent static instruction class.
*
* This class builds on StaticInstBase, defining fields and interfaces
* that are generic across all ISAs but that differ in details
* according to the specific ISA being used.
*/
template <class ISA>
class StaticInst : public StaticInstBase
{
public:
/// Binary machine instruction type.
typedef typename ISA::MachInst MachInst;
/// Memory address type.
typedef typename ISA::Addr Addr;
/// Logical register index type.
typedef typename ISA::RegIndex RegIndex;
enum {
MaxInstSrcRegs = ISA::MaxInstSrcRegs, //< Max source regs
MaxInstDestRegs = ISA::MaxInstDestRegs, //< Max dest regs
};
/// Return logical index (architectural reg num) of i'th destination reg.
/// Only the entries from 0 through numDestRegs()-1 are valid.
RegIndex destRegIdx(int i) const { return _destRegIdx[i]; }
/// Return logical index (architectural reg num) of i'th source reg.
/// Only the entries from 0 through numSrcRegs()-1 are valid.
RegIndex srcRegIdx(int i) const { return _srcRegIdx[i]; }
/// Pointer to a statically allocated "null" instruction object.
/// Used to give eaCompInst() and memAccInst() something to return
/// when called on non-memory instructions.
static StaticInstPtr<ISA> nullStaticInstPtr;
/**
* Memory references only: returns "fake" instruction representing
* the effective address part of the memory operation. Used to
* obtain the dependence info (numSrcRegs and srcRegIdx[]) for
* just the EA computation.
*/
virtual const
StaticInstPtr<ISA> &eaCompInst() const { return nullStaticInstPtr; }
/**
* Memory references only: returns "fake" instruction representing
* the memory access part of the memory operation. Used to
* obtain the dependence info (numSrcRegs and srcRegIdx[]) for
* just the memory access (not the EA computation).
*/
virtual const
StaticInstPtr<ISA> &memAccInst() const { return nullStaticInstPtr; }
/// The binary machine instruction.
const MachInst machInst;
protected:
/// See destRegIdx().
RegIndex _destRegIdx[MaxInstDestRegs];
/// See srcRegIdx().
RegIndex _srcRegIdx[MaxInstSrcRegs];
/**
* Base mnemonic (e.g., "add"). Used by generateDisassembly()
* methods. Also useful to readily identify instructions from
* within the debugger when #cachedDisassembly has not been
* initialized.
*/
const char *mnemonic;
/**
* String representation of disassembly (lazily evaluated via
* disassemble()).
*/
std::string *cachedDisassembly;
/**
* Internal function to generate disassembly string.
*/
virtual std::string generateDisassembly(Addr pc,
const SymbolTable *symtab) = 0;
/// Constructor.
StaticInst(const char *_mnemonic, MachInst _machInst, OpClass __opClass)
: StaticInstBase(__opClass),
machInst(_machInst), mnemonic(_mnemonic), cachedDisassembly(0)
{
}
public:
virtual ~StaticInst()
{
if (cachedDisassembly)
delete cachedDisassembly;
}
/**
* Execute this instruction under SimpleCPU model.
*/
virtual Fault execute(SimpleCPU *xc, Trace::InstRecord *traceData) = 0;
/**
* Execute this instruction under detailed FullCPU model.
*/
virtual Fault execute(DynInst *xc, Trace::InstRecord *traceData) = 0;
/**
* Return the target address for a PC-relative branch.
* Invalid if not a PC-relative branch (i.e. isDirectCtrl()
* should be true).
*/
virtual Addr branchTarget(Addr branchPC) const
{
panic("StaticInst::branchTarget() called on instruction "
"that is not a PC-relative branch.");
}
/**
* Return the target address for an indirect branch (jump). The
* register value is read from the supplied execution context, so
* the result is valid only if the execution context is about to
* execute the branch in question. Invalid if not an indirect
* branch (i.e. isIndirectCtrl() should be true).
*/
virtual Addr branchTarget(ExecContext *xc) const
{
panic("StaticInst::branchTarget() called on instruction "
"that is not an indirect branch.");
}
/**
* Return true if the instruction is a control transfer, and if so,
* return the target address as well.
*/
bool hasBranchTarget(Addr pc, ExecContext *xc, Addr &tgt);
/**
* Return string representation of disassembled instruction.
* The default version of this function will call the internal
* virtual generateDisassembly() function to get the string,
* then cache it in #cachedDisassembly. If the disassembly
* should not be cached, this function should be overridden directly.
*/
virtual const std::string &disassemble(Addr pc,
const SymbolTable *symtab = 0)
{
if (!cachedDisassembly)
cachedDisassembly =
new std::string(generateDisassembly(pc, symtab));
return *cachedDisassembly;
}
/// Decoded instruction cache type.
/// For now we're using a generic hash_map; this seems to work
/// pretty well.
typedef m5::hash_map<MachInst, StaticInstPtr<ISA> > DecodeCache;
/// A cache of decoded instruction objects.
static DecodeCache decodeCache;
/**
* Dump some basic stats on the decode cache hash map.
* Only gets called if DECODE_CACHE_HASH_STATS is defined.
*/
static void dumpDecodeCacheStats();
/// Decode a machine instruction.
/// @param mach_inst The binary instruction to decode.
/// @retval A pointer to the corresponding StaticInst object.
static
StaticInstPtr<ISA> decode(MachInst mach_inst)
{
#ifdef DECODE_CACHE_HASH_STATS
// Simple stats on decode hash_map. Turns out the default
// hash function is as good as anything I could come up with.
const int dump_every_n = 10000000;
static int decodes_til_dump = dump_every_n;
if (--decodes_til_dump == 0) {
dumpDecodeCacheStats();
decodes_til_dump = dump_every_n;
}
#endif
typename DecodeCache::iterator iter = decodeCache.find(mach_inst);
if (iter != decodeCache.end()) {
return iter->second;
}
StaticInstPtr<ISA> si = ISA::decodeInst(mach_inst);
decodeCache[mach_inst] = si;
return si;
}
};
typedef RefCountingPtr<StaticInstBase> StaticInstBasePtr;
/// Reference-counted pointer to a StaticInst object.
/// This type should be used instead of "StaticInst<ISA> *" so that
/// StaticInst objects can be properly reference-counted.
template <class ISA>
class StaticInstPtr : public RefCountingPtr<StaticInst<ISA> >
{
public:
/// Constructor.
StaticInstPtr()
: RefCountingPtr<StaticInst<ISA> >()
{
}
/// Conversion from "StaticInst<ISA> *".
StaticInstPtr(StaticInst<ISA> *p)
: RefCountingPtr<StaticInst<ISA> >(p)
{
}
/// Copy constructor.
StaticInstPtr(const StaticInstPtr &r)
: RefCountingPtr<StaticInst<ISA> >(r)
{
}
/// Construct directly from machine instruction.
/// Calls StaticInst<ISA>::decode().
StaticInstPtr(typename ISA::MachInst mach_inst)
: RefCountingPtr<StaticInst<ISA> >(StaticInst<ISA>::decode(mach_inst))
{
}
/// Convert to pointer to StaticInstBase class.
operator const StaticInstBasePtr()
{
return get();
}
};
#endif // __STATIC_INST_HH__