llvm-6502/lib/Target/TargetMachine.cpp
Chris Lattner 78a81a24e1 Add a comment
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@571 91177308-0d34-0410-b5e6-96231b3b80d8
2001-09-14 16:08:12 +00:00

80 lines
2.3 KiB
C++

//===-- TargetMachine.cpp - General Target Information ---------------------==//
//
// This file describes the general parts of a Target machine.
// This file also implements the InstInfo interface as well...
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/InstInfo.h"
#include "llvm/DerivedTypes.h"
//---------------------------------------------------------------------------
// class TargetMachine
//
// Purpose:
// Machine description.
//
//---------------------------------------------------------------------------
// function TargetMachine::findOptimalStorageSize
//
// Purpose:
// This default implementation assumes that all sub-word data items use
// space equal to optSizeForSubWordData, and all other primitive data
// items use space according to the type.
//
unsigned int TargetMachine::findOptimalStorageSize(const Type* ty) const {
switch(ty->getPrimitiveID()) {
case Type::BoolTyID:
case Type::UByteTyID:
case Type::SByteTyID:
case Type::UShortTyID:
case Type::ShortTyID:
return optSizeForSubWordData;
default:
return DataLayout.getTypeSize(ty);
}
}
//---------------------------------------------------------------------------
// class MachineInstructionInfo
// Interface to description of machine instructions
//---------------------------------------------------------------------------
/*ctor*/
MachineInstrInfo::MachineInstrInfo(const MachineInstrDescriptor* _desc,
unsigned int _descSize,
unsigned int _numRealOpCodes)
: desc(_desc), descSize(_descSize), numRealOpCodes(_numRealOpCodes)
{
// FIXME: TargetInstrDescriptors should not be global
assert(TargetInstrDescriptors == NULL && desc != NULL);
TargetInstrDescriptors = desc; // initialize global variable
}
MachineInstrInfo::~MachineInstrInfo() {
TargetInstrDescriptors = NULL; // reset global variable
}
bool
MachineInstrInfo::constantFitsInImmedField(MachineOpCode opCode,
int64_t intValue) const
{
// First, check if opCode has an immed field.
bool isSignExtended;
uint64_t maxImmedValue = maxImmedConstant(opCode, isSignExtended);
if (maxImmedValue != 0) {
// Now check if the constant fits
if (intValue <= (int64_t) maxImmedValue &&
intValue >= -((int64_t) maxImmedValue+1))
return true;
}
return false;
}