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// -*- mode:c++ -*-
////////////////////////////////////////////////////////////////////
//
// Nop
//
output header {{
/**
* Static instruction class for no-ops. This is a leaf class.
*/
class Nop : public MipsStaticInst
{
/// Disassembly of original instruction.
const std::string originalDisassembly;
public:
/// Constructor
Nop(const std::string _originalDisassembly, MachInst _machInst)
: MipsStaticInst("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
MipsStaticInst *
makeNop(MipsStaticInst *inst)
{
MipsStaticInst *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 RT as dest, so check for
// RT == 0 to detect nops
def template OperateNopCheckDecode {{
{
MipsStaticInst *i = new %(class_name)s(machInst);
if (RD == 0) {
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, 'MipsStaticInst', CodeBlock(code),
opt_args)
header_output = BasicDeclare.subst(iop)
decoder_output = BasicConstructor.subst(iop)
decode_block = OperateNopCheckDecode.subst(iop)
exec_output = BasicExecute.subst(iop)
}};
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