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base: Rework bitunions so they can be more flexible.

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They are now oriented around a class which makes it easy to provide
custom setter/getter functions which let you set or read bits in an
arbitrary way.

Future additions may add the ability to add custom bitfield methods,
and index-able bitfields.

Change-Id: Ibd6d4d9e49107490f6dad30a4379a8c93bda9333
Reviewed-on: https://gem5-review.googlesource.com/7201
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
This commit is contained in:
Gabe Black
2018-01-06 05:30:46 -08:00
parent ecec887507
commit cd9450c1d9
6 changed files with 250 additions and 193 deletions
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4
src/arch/arm/types.hh
View File

@@ -741,10 +741,10 @@ namespace std {
template<>
struct hash<ArmISA::ExtMachInst> :
public hash<ArmISA::ExtMachInst::__DataType> {
public hash<ArmISA::ExtMachInst::__StorageType> {
size_t operator()(const ArmISA::ExtMachInst &emi) const {
return hash<ArmISA::ExtMachInst::__DataType>::operator()(emi);
return hash<ArmISA::ExtMachInst::__StorageType>::operator()(emi);
}
};

348
src/base/bitunion.hh
View File

@@ -31,6 +31,9 @@
#ifndef __BASE_BITUNION_HH__
#define __BASE_BITUNION_HH__
#include <iostream>
#include <type_traits>
#include "base/bitfield.hh"
// The following implements the BitUnion system of defining bitfields
@@ -41,210 +44,230 @@
//without having to have access to each other. More details are provided with
//the individual components.
//This class wraps around another which defines getter/setter functions which
//manipulate the underlying data. The type of the underlying data and the type
//of the bitfield itself are inferred from the argument types of the setter
//function.
template<class Base>
class BitfieldTypeImpl : public Base
{
static_assert(std::is_empty<Base>::value,
"Bitfield base class must be empty.");
private:
using Base::setter;
template<typename T>
struct TypeDeducer;
template<typename T>
friend class TypeDeducer;
template<typename Type1, typename Type2>
struct TypeDeducer<void (Base::*)(Type1 &, Type2)>
{
typedef Type1 Storage;
typedef Type2 Type;
};
protected:
typedef typename TypeDeducer<
decltype(&BitfieldTypeImpl<Base>::setter)>::Storage Storage;
typedef typename TypeDeducer<
decltype(&BitfieldTypeImpl<Base>::setter)>::Type Type;
Type getter(const Storage &storage) const = delete;
void setter(Storage &storage, Type val) = delete;
Storage __storage;
operator Type () const
{
return Base::getter(__storage);
}
Type
operator=(const Type val)
{
Base::setter(__storage, val);
return val;
}
Type
operator=(BitfieldTypeImpl<Base> const & other)
{
return *this = (Type)other;
}
};
//A wrapper for the above class which allows setting and getting.
template<class Base>
class BitfieldType : public BitfieldTypeImpl<Base>
{
protected:
using Impl = BitfieldTypeImpl<Base>;
using typename Impl::Type;
public:
operator Type () const { return Impl::operator Type(); }
Type operator=(const Type val) { return Impl::operator=(val); }
Type
operator=(BitfieldType<Base> const & other)
{
return Impl::operator=(other);
}
};
//A wrapper which only supports getting.
template<class Base>
class BitfieldROType : public BitfieldTypeImpl<Base>
{
public:
using Impl = BitfieldTypeImpl<Base>;
using typename Impl::Type;
Type operator=(BitfieldROType<Base> const &other) = delete;
operator Type () const { return Impl::operator Type(); }
};
//A wrapper which only supports setting.
template <class Base>
class BitfieldWOType : public BitfieldTypeImpl<Base>
{
protected:
using Impl = BitfieldTypeImpl<Base>;
using typename Impl::Type;
public:
Type operator=(const Type val) { return Impl::operator=(val); }
Type
operator=(BitfieldWOType<Base> const & other)
{
return Impl::operator=(other);
}
};
//This namespace is for classes which implement the backend of the BitUnion
//stuff. Don't use any of these directly, except for the Bitfield classes in
//the *BitfieldTypes class(es).
//stuff. Don't use any of these directly.
namespace BitfieldBackend
{
//A base class for all bitfields. It instantiates the actual storage,
//and provides getBits and setBits functions for manipulating it. The
//Data template parameter is type of the underlying storage.
template<class Data>
class BitfieldBase
template<class Storage, int first, int last>
class Unsigned
{
protected:
Data __data;
static_assert(first >= last,
"Bitfield ranges must be specified as <msb, lsb>");
//This function returns a range of bits from the underlying storage.
//It relies on the "bits" function above. It's the user's
//responsibility to make sure that there is a properly overloaded
//version of this function for whatever type they want to overlay.
inline uint64_t
getBits(int first, int last) const
protected:
uint64_t
getter(const Storage &storage) const
{
return bits(__data, first, last);
return bits(storage, first, last);
}
//Similar to the above, but for settings bits with replaceBits.
inline void
setBits(int first, int last, uint64_t val)
void
setter(Storage &storage, uint64_t val)
{
replaceBits(__data, first, last, val);
replaceBits(storage, first, last, val);
}
};
//This class contains all the "regular" bitfield classes. It is inherited
//by all BitUnions which give them access to those types.
template<class Type>
class RegularBitfieldTypes
template<class Storage, int first, int last>
class Signed
{
static_assert(first >= last,
"Bitfield ranges must be specified as <msb, lsb>");
protected:
//This class implements ordinary bitfields, that is a span of bits
//who's msb is "first", and who's lsb is "last".
template<int first, int last=first>
class Bitfield : public BitfieldBase<Type>
int64_t
getter(const Storage &storage) const
{
static_assert(first >= last,
"Bitfield ranges must be specified as <msb, lsb>");
return sext<first - last + 1>(bits(storage, first, last));
}
public:
operator uint64_t () const
{
return this->getBits(first, last);
}
uint64_t
operator=(const uint64_t _data)
{
this->setBits(first, last, _data);
return _data;
}
uint64_t
operator=(Bitfield<first, last> const & other)
{
return *this = (uint64_t)other;
}
};
//A class which specializes the above so that it can only be read
//from. This is accomplished explicitly making sure the assignment
//operator is blocked. The conversion operator is carried through
//inheritance. This will unfortunately need to be copied into each
//bitfield type due to limitations with how templates work
template<int first, int last=first>
class BitfieldRO : public Bitfield<first, last>
void
setter(Storage &storage, int64_t val)
{
private:
uint64_t
operator=(const uint64_t _data);
uint64_t
operator=(const Bitfield<first, last>& other);
};
//Similar to the above, but only allows writing.
template<int first, int last=first>
class BitfieldWO : public Bitfield<first, last>
{
private:
operator uint64_t () const;
public:
using Bitfield<first, last>::operator=;
};
replaceBits(storage, first, last, val);
}
};
//This class contains all the "regular" bitfield classes. It is inherited
//by all BitUnions which give them access to those types.
template<class Type>
class SignedBitfieldTypes
//This class contains the basic bitfield types which are automatically
//available within a BitUnion. They inherit their Storage type from the
//containing BitUnion.
template<class Storage>
class BitfieldTypes
{
protected:
//This class implements ordinary bitfields, that is a span of bits
//who's msb is "first", and who's lsb is "last".
template<int first, int last=first>
class SignedBitfield : public BitfieldBase<Type>
{
public:
operator int64_t () const
{
return sext<first - last + 1>(this->getBits(first, last));
}
int64_t
operator=(const int64_t _data)
{
this->setBits(first, last, _data);
return _data;
}
int64_t
operator=(SignedBitfield<first, last> const & other)
{
return *this = (int64_t)other;
}
};
//A class which specializes the above so that it can only be read
//from. This is accomplished explicitly making sure the assignment
//operator is blocked. The conversion operator is carried through
//inheritance. This will unfortunately need to be copied into each
//bitfield type due to limitations with how templates work
using Bitfield = BitfieldType<Unsigned<Storage, first, last> >;
template<int first, int last=first>
class SignedBitfieldRO : public SignedBitfield<first, last>
{
private:
int64_t
operator=(const int64_t _data);
int64_t
operator=(const SignedBitfield<first, last>& other);
};
//Similar to the above, but only allows writing.
using BitfieldRO =
BitfieldROType<Unsigned<Storage, first, last> >;
template<int first, int last=first>
class SignedBitfieldWO : public SignedBitfield<first, last>
{
private:
operator int64_t () const;
using BitfieldWO =
BitfieldWOType<Unsigned<Storage, first, last> >;
public:
using SignedBitfield<first, last>::operator=;
};
template<int first, int last=first>
using SignedBitfield =
BitfieldType<Signed<Storage, first, last> >;
template<int first, int last=first>
using SignedBitfieldRO =
BitfieldROType<Signed<Storage, first, last> >;
template<int first, int last=first>
using SignedBitfieldWO =
BitfieldWOType<Signed<Storage, first, last> >;
};
template<class Type>
class BitfieldTypes : public RegularBitfieldTypes<Type>,
public SignedBitfieldTypes<Type>
{};
//When a BitUnion is set up, an underlying class is created which holds
//the actual union. This class then inherits from it, and provids the
//implementations for various operators. Setting things up this way
//prevents having to redefine these functions in every different BitUnion
//type. More operators could be implemented in the future, as the need
//arises.
template <class Type, class Base>
template <class Base>
class BitUnionOperators : public Base
{
static_assert(sizeof(Base) == sizeof(typename Base::__StorageType),
"BitUnion larger than its storage type.");
public:
BitUnionOperators(Type const & _data)
BitUnionOperators(typename Base::__StorageType const &val)
{
Base::__data = _data;
Base::__storage = val;
}
BitUnionOperators() {}
operator const Type () const
operator const typename Base::__StorageType () const
{
return Base::__data;
return Base::__storage;
}
Type
operator=(Type const & _data)
typename Base::__StorageType
operator=(typename Base::__StorageType const &val)
{
Base::__data = _data;
return _data;
Base::__storage = val;
return val;
}
Type
operator=(BitUnionOperators const & other)
typename Base::__StorageType
operator=(BitUnionOperators const &other)
{
Base::__data = other;
return Base::__data;
Base::__storage = other;
return Base::__storage;
}
bool
operator<(Base const & base) const
operator<(Base const &base) const
{
return Base::__data < base.__data;
return Base::__storage < base.__storage;
}
bool
operator==(Base const & base) const
operator==(Base const &base) const
{
return Base::__data == base.__data;
return Base::__storage == base.__storage;
}
};
}
@@ -256,12 +279,12 @@ namespace BitfieldBackend
//namespace ensures that there will be no collisions with other names as long
//as the BitUnion names themselves are all distinct and nothing else uses
//the BitfieldUnderlyingClasses namespace, which is unlikely. The class itself
//creates a typedef of the "type" parameter called __DataType. This allows
//creates a typedef of the "type" parameter called __StorageType. This allows
//the type to propagate outside of the macro itself in a controlled way.
//Finally, the base storage is defined which BitfieldOperators will refer to
//in the operators it defines. This macro is intended to be followed by
//bitfield definitions which will end up inside it's union. As explained
//above, these is overlayed the __data member in its entirety by each of the
//above, these is overlayed the __storage member in its entirety by each of the
//bitfields which are defined in the union, creating shared storage with no
//overhead.
#define __BitUnion(type, name) \
@@ -269,9 +292,9 @@ namespace BitfieldBackend
public BitfieldBackend::BitfieldTypes<type> \
{ \
public: \
typedef type __DataType; \
typedef type __StorageType; \
union { \
type __data;\
type __storage;
//This closes off the class and union started by the above macro. It is
//followed by a typedef which makes "name" refer to a BitfieldOperator
@@ -281,20 +304,19 @@ namespace BitfieldBackend
}; \
}; \
typedef BitfieldBackend::BitUnionOperators< \
BitfieldUnderlyingClasses##name::__DataType, \
BitfieldUnderlyingClasses##name> name;
//This sets up a bitfield which has other bitfields nested inside of it. The
//__data member functions like the "underlying storage" of the top level
//__storage member functions like the "underlying storage" of the top level
//BitUnion. Like everything else, it overlays with the top level storage, so
//making it a regular bitfield type makes the entire thing function as a
//regular bitfield when referred to by itself.
#define __SubBitUnion(fieldType, first, last, name) \
class : public BitfieldBackend::BitfieldTypes<__DataType> \
#define __SubBitUnion(name, fieldType, ...) \
class \
{ \
public: \
union { \
fieldType<first, last> __data;
fieldType<__VA_ARGS__> __storage;
//This closes off the union created above and gives it a name. Unlike the top
//level BitUnion, we're interested in creating an object instead of a type.
@@ -303,22 +325,22 @@ namespace BitfieldBackend
//do so.
#define EndSubBitUnion(name) \
}; \
inline operator __DataType () const \
{ return __data; } \
inline operator __StorageType () const \
{ return __storage; } \
\
inline __DataType operator = (const __DataType & _data) \
{ return __data = _data;} \
inline __StorageType operator = (const __StorageType & _storage) \
{ return __storage = _storage;} \
} name;
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SubBitUnion(name, first, last) \
__SubBitUnion(Bitfield, first, last, name)
__SubBitUnion(name, Bitfield, first, last)
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SignedSubBitUnion(name, first, last) \
__SubBitUnion(SignedBitfield, first, last, name)
__SubBitUnion(name, SignedBitfield, first, last)
//Use this to define an arbitrary type overlayed with bitfields.
#define BitUnion(type, name) __BitUnion(type, name)

49
src/base/bituniontest.cc
View File

@@ -66,6 +66,44 @@ EndBitUnion(EmptySixteen)
BitUnion8(EmptyEight)
EndBitUnion(EmptyEight)
class SplitField
{
protected:
BitUnion64(In)
Bitfield<15, 12> high;
Bitfield<7, 4> low;
EndBitUnion(In)
BitUnion64(Out)
Bitfield<7, 4> high;
Bitfield<3, 0> low;
EndBitUnion(Out)
public:
uint64_t
getter(const uint64_t &storage) const
{
Out out = 0;
In in = storage;
out.high = in.high;
out.low = in.low;
return out;
}
void
setter(uint64_t &storage, uint64_t val)
{
Out out = val;
In in = 0;
in.high = out.high;
in.low = out.low;
storage = in;
}
};
BitUnion64(Split)
BitfieldType<SplitField> split;
EndBitUnion(Split)
struct ContainingStruct
{
BitUnion64(Contained)
@@ -99,8 +137,9 @@ EmptyEight emptyEight(0);
class BitUnionData : public testing::Test {
protected:
SixtyFour sixtyFour;
Split split;
void SetUp() override { sixtyFour = 0; }
void SetUp() override { sixtyFour = 0; split = 0; }
};
TEST_F(BitUnionData, NormalBitfield)
@@ -192,3 +231,11 @@ TEST_F(BitUnionData, Operators)
sixtyFour = otherSixtyFour;
EXPECT_TRUE(sixtyFour == otherSixtyFour);
}
TEST_F(BitUnionData, Custom)
{
EXPECT_EQ(split, 0);
split.split = 0xfff;
EXPECT_EQ(split, 0xf0f0);
EXPECT_EQ((uint64_t)split.split, 0xff);
}

17
src/dev/x86/i8042.cc
View File

@@ -491,13 +491,10 @@ X86ISA::I8042::write(PacketPtr pkt)
void
X86ISA::I8042::serialize(CheckpointOut &cp) const
{
uint8_t statusRegData = statusReg.__data;
uint8_t commandByteData = commandByte.__data;
SERIALIZE_SCALAR(dataPort);
SERIALIZE_SCALAR(commandPort);
SERIALIZE_SCALAR(statusRegData);
SERIALIZE_SCALAR(commandByteData);
SERIALIZE_SCALAR(statusReg);
SERIALIZE_SCALAR(commandByte);
SERIALIZE_SCALAR(dataReg);
SERIALIZE_SCALAR(lastCommand);
mouse.serialize("mouse", cp);
@@ -507,20 +504,14 @@ X86ISA::I8042::serialize(CheckpointOut &cp) const
void
X86ISA::I8042::unserialize(CheckpointIn &cp)
{
uint8_t statusRegData;
uint8_t commandByteData;
UNSERIALIZE_SCALAR(dataPort);
UNSERIALIZE_SCALAR(commandPort);
UNSERIALIZE_SCALAR(statusRegData);
UNSERIALIZE_SCALAR(commandByteData);
UNSERIALIZE_SCALAR(statusReg);
UNSERIALIZE_SCALAR(commandByte);
UNSERIALIZE_SCALAR(dataReg);
UNSERIALIZE_SCALAR(lastCommand);
mouse.unserialize("mouse", cp);
keyboard.unserialize("keyboard", cp);
statusReg.__data = statusRegData;
commandByte.__data = commandByteData;
}
void

7
src/dev/x86/speaker.cc
View File

@@ -77,16 +77,13 @@ X86ISA::Speaker::write(PacketPtr pkt)
void
X86ISA::Speaker::serialize(CheckpointOut &cp) const
{
uint8_t controlValData = controlVal.__data;
SERIALIZE_SCALAR(controlValData);
SERIALIZE_SCALAR(controlVal);
}
void
X86ISA::Speaker::unserialize(CheckpointIn &cp)
{
uint8_t controlValData;
UNSERIALIZE_SCALAR(controlValData);
controlVal.__data = controlValData;
UNSERIALIZE_SCALAR(controlVal);
}
X86ISA::Speaker *

18
src/sim/serialize.hh
View File

@@ -72,33 +72,33 @@ typedef std::ostream CheckpointOut;
template <class T>
void paramOut(CheckpointOut &cp, const std::string &name, const T &param);
template <typename DataType, typename BitUnion>
template <typename BitUnion>
void paramOut(CheckpointOut &cp, const std::string &name,
const BitfieldBackend::BitUnionOperators<DataType, BitUnion> &p)
const BitfieldBackend::BitUnionOperators<BitUnion> &p)
{
paramOut(cp, name, p.__data);
paramOut(cp, name, p.__storage);
}
template <class T>
void paramIn(CheckpointIn &cp, const std::string &name, T &param);
template <typename DataType, typename BitUnion>
template <typename BitUnion>
void paramIn(CheckpointIn &cp, const std::string &name,
BitfieldBackend::BitUnionOperators<DataType, BitUnion> &p)
BitfieldBackend::BitUnionOperators<BitUnion> &p)
{
paramIn(cp, name, p.__data);
paramIn(cp, name, p.__storage);
}
template <class T>
bool optParamIn(CheckpointIn &cp, const std::string &name, T &param,
bool warn = true);
template <typename DataType, typename BitUnion>
template <typename BitUnion>
bool optParamIn(CheckpointIn &cp, const std::string &name,
BitfieldBackend::BitUnionOperators<DataType, BitUnion> &p,
BitfieldBackend::BitUnionOperators<BitUnion> &p,
bool warn = true)
{
return optParamIn(cp, name, p.__data, warn);
return optParamIn(cp, name, p.__storage, warn);
}
template <class T>