nop.isa

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· ISA 代码 · 共 69 行

////////////////////////////////////////////////////////////////////
//
// Nop instruction
//

// Per-cpu-model nop execute method.
def template NopExec {{

    Fault execute(%(CPU_exec_context)s *xc, Trace::InstRecord *traceData) const
    {
        // Nothing to see here, move along
        return NoFault;
    }
}};

output header {{
        /**
         * Nop class.
         */
        class Nop : public SparcStaticInst
        {
          public:
            // Constructor
            Nop(const char *mnem, ExtMachInst _machInst, OpClass __opClass) :
                SparcStaticInst(mnem, _machInst, __opClass)
            {
                flags[IsNop] = true;
            }

            // All Nop instructions do the same thing, so this can be
            // defined here. Nops can be defined directly, so there
            // needs to be a default implementation.  Interpolate via
            // template so i gets expanded to a set of
            // cpu-model-specific functions.
            %(NopExec)s

            std::string generateDisassembly(Addr pc,
                    const SymbolTable *symtab) const;
        };
}};

output decoder {{
        std::string Nop::generateDisassembly(Addr pc,
                const SymbolTable *symtab) const
        {
            std::stringstream response;
            printMnemonic(response, mnemonic);
            return response.str();
        }
}};

def template NopExecute {{
        Fault %(class_name)s::execute(%(CPU_exec_context)s *xc,
                Trace::InstRecord *traceData) const
        {
            //Nothing to see here, move along
            return NoFault;
        }
}};

// Primary format for integer operate instructions:
def format Nop(code, *opt_flags) {{
        iop = InstObjParams(name, Name, 'Nop', code, opt_flags)
        header_output = BasicDeclare.subst(iop)
        decoder_output = BasicConstructor.subst(iop)
        decode_block = BasicDecode.subst(iop)
        exec_output = NopExecute.subst(iop)
}};