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// -*- mode:c++ -*-
// Copyright (c) 2007 MIPS Technologies, Inc.
// 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.
//
// Authors: Korey Sewell
////////////////////////////////////////////////////////////////////
//
// 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 override;
Fault execute(ExecContext *, Trace::InstRecord *) const override;
};
}};
output decoder {{
std::string Nop::generateDisassembly(Addr pc,
const SymbolTable *symtab) const
{
return csprintf("%-10s %s", "nop", originalDisassembly);
}
/// Helper function for decoding nops. Substitute Nop object
/// for original inst passed in as arg (and delete latter).
inline
MipsStaticInst *
makeNop(MipsStaticInst *inst)
{
std::string nop_str = "(" + inst->disassemble(0) + ")";
MipsStaticInst *nop = new Nop(nop_str, inst->machInst);
delete inst;
return nop;
}
}};
output exec {{
Fault
Nop::execute(ExecContext *, Trace::InstRecord *) const
{
return NoFault;
}
}};
// Int & FP operate instructions use RD as dest, so check for
// RD == 0 to detect nops
def template RegNopCheckDecode {{
{
MipsStaticInst *i = new %(class_name)s(machInst);
//if (RD == 0) {
//i = makeNop(i);
//}
return i;
}
}};
def template OperateNopCheckDecode {{
{
MipsStaticInst *i = new %(class_name)s(machInst);
//if (RD == 0) {
// i = makeNop(i);
//}
return i;
}
}};
// IntImm & Memory instructions use Rt as dest, so check for
// Rt == 0 to detect nops
def template ImmNopCheckDecode {{
{
MipsStaticInst *i = new %(class_name)s(machInst);
//if (RT == 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', code,
opt_args)
header_output = BasicDeclare.subst(iop)
decoder_output = BasicConstructor.subst(iop)
decode_block = OperateNopCheckDecode.subst(iop)
exec_output = BasicExecute.subst(iop)
}};
def format Nop() {{
decode_block = 'return new Nop(\"\",machInst);\n'
}};
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