gem5/arch/mips/isa/formats/noop.isa

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////////////////////////////////////////////////////////////////////
//
// Noop instruction
//
output header {{
/**
* Base class for integer operations.
*/
class Noop : public MipsStaticInst
{
protected:
/// Constructor
Noop(const char *mnem, MachInst _machInst, OpClass __opClass) : MipsStaticInst(mnem, _machInst, __opClass)
{
}
std::string generateDisassembly(Addr pc, const SymbolTable *symtab) const;
};
}};
output decoder {{
std::string Noop::generateDisassembly(Addr pc, const SymbolTable *symtab) const
{
return "Disassembly of integer instruction\n";
}
}};
def template NoopExecute {{
Fault %(class_name)s::execute(%(CPU_exec_context)s *xc, Trace::InstRecord *traceData) const
{
//Nothing to see here, move along
return No_Fault;
}
}};
// Primary format for integer operate instructions:
def format Noop(code, *opt_flags) {{
orig_code = code
cblk = CodeBlock(code)
iop = InstObjParams(name, Name, 'MipsStaticInst', cblk, opt_flags)
header_output = BasicDeclare.subst(iop)
decoder_output = BasicConstructor.subst(iop)
decode_block = BasicDecodeWithMnemonic.subst(iop)
exec_output = NoopExecute.subst(iop)
}};
////////////////////////////////////////////////////////////////////
//
// Nop
//
output header {{
/**
* Static instruction class for no-ops. This is a leaf class.
*/
class Nop : public AlphaStaticInst
{
/// Disassembly of original instruction.
const std::string originalDisassembly;
public:
/// Constructor
Nop(const std::string _originalDisassembly, MachInst _machInst)
: AlphaStaticInst("nop", _machInst, No_OpClass),
originalDisassembly(_originalDisassembly)
{
flags[IsNop] = true;
}
~Nop() { }
std::string
generateDisassembly(Addr pc, const SymbolTable *symtab) const;
%(BasicExecDeclare)s
};
}};
output decoder {{
std::string Nop::generateDisassembly(Addr pc,
const SymbolTable *symtab) const
{
#ifdef SS_COMPATIBLE_DISASSEMBLY
return originalDisassembly;
#else
return csprintf("%-10s (%s)", "nop", originalDisassembly);
#endif
}
/// Helper function for decoding nops. Substitute Nop object
/// for original inst passed in as arg (and delete latter).
inline
AlphaStaticInst *
makeNop(AlphaStaticInst *inst)
{
AlphaStaticInst *nop = new Nop(inst->disassemble(0), inst->machInst);
delete inst;
return nop;
}
}};
output exec {{
Fault
Nop::execute(%(CPU_exec_context)s *, Trace::InstRecord *) const
{
return No_Fault;
}
}};
// integer & FP operate instructions use Rc as dest, so check for
// Rc == 31 to detect nops
def template OperateNopCheckDecode {{
{
AlphaStaticInst *i = new %(class_name)s(machInst);
if (RC == 31) {
i = makeNop(i);
}
return i;
}
}};
// Like BasicOperate format, but generates NOP if RC/FC == 31
def format BasicOperateWithNopCheck(code, *opt_args) {{
iop = InstObjParams(name, Name, 'AlphaStaticInst', CodeBlock(code),
opt_args)
header_output = BasicDeclare.subst(iop)
decoder_output = BasicConstructor.subst(iop)
decode_block = OperateNopCheckDecode.subst(iop)
exec_output = BasicExecute.subst(iop)
}};