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Move bitunion code into it's own file.

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--HG--
extra : convert_revision : 8d55ca9645ee4e357b7f4595435542eb72490331
This commit is contained in:
Gabe Black 2007-07-14 17:28:26 -07:00
parent 4f7809d5e6
commit 873b762d4b
4 changed files with 308 additions and 271 deletions
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2
src/arch/x86/intregs.hh
View file

@ -58,7 +58,7 @@
#ifndef __ARCH_X86_INTREGS_HH__
#define __ARCH_X86_INTREGS_HH__
#include "base/bitfield.hh"
#include "base/bitunion.hh"
namespace X86ISA
{

2
src/arch/x86/types.hh
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@ -61,7 +61,7 @@
#include <inttypes.h>
#include <iostream>
#include "base/bitfield.hh"
#include "base/bitunion.hh"
#include "base/cprintf.hh"
namespace X86ISA

269
src/base/bitfield.hh
View file

@ -161,273 +161,4 @@ findMsbSet(uint64_t val) {
return msb;
}
// The following implements the BitUnion system of defining bitfields
//on top of an underlying class. This is done through the pervasive use of
//both named and unnamed unions which all contain the same actual storage.
//Since they're unioned with each other, all of these storage locations
//overlap. This allows all of the bitfields to manipulate the same data
//without having to have access to each other. More details are provided with the
//individual components.
//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).
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
{
protected:
Data __data;
//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
{
return bits(__data, first, last);
}
//Similar to the above, but for settings bits with replaceBits.
inline void
setBits(int first, int last, uint64_t val)
{
replaceBits(__data, 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
{
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>
{
public:
operator uint64_t () const
{
return this->getBits(first, last);
}
uint64_t
operator=(const uint64_t _data)
{
this->setBits(first, last, _data);
return _data;
}
};
//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>
{
private:
uint64_t
operator=(const uint64_t _data);
};
//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=;
};
};
//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
{
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;
}
};
//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 SignedBitfieldRO : public SignedBitfield<first, last>
{
private:
int64_t
operator=(const int64_t _data);
};
//Similar to the above, but only allows writing.
template<int first, int last=first>
class SignedBitfieldWO : public SignedBitfield<first, last>
{
private:
operator int64_t () const;
public:
int64_t operator=(const int64_t _data)
{
*((SignedBitfield<first, last> *)this) = _data;
return _data;
}
};
};
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>
class BitUnionOperators : public Base
{
public:
operator Type () const
{
return Base::__data;
}
Type
operator=(const Type & _data)
{
Base::__data = _data;
return _data;
}
bool
operator<(const Base & base) const
{
return Base::__data < base.__data;
}
bool
operator==(const Base & base) const
{
return Base::__data == base.__data;
}
};
}
//This macro is a backend for other macros that specialize it slightly.
//First, it creates/extends a namespace "BitfieldUnderlyingClasses" and
//sticks the class which has the actual union in it, which
//BitfieldOperators above inherits from. Putting these classes in a special
//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
//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
//bitfields which are defined in the union, creating shared storage with no
//overhead.
#define __BitUnion(type, name) \
namespace BitfieldUnderlyingClasses \
{ \
class name; \
} \
class BitfieldUnderlyingClasses::name : \
public BitfieldBackend::BitfieldTypes<type> \
{ \
public: \
typedef type __DataType; \
union { \
type __data;\
//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
//class inheriting from the class and union just defined, which completes
//building up the type for the user.
#define EndBitUnion(name) \
}; \
}; \
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
//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> \
{ \
public: \
union { \
fieldType<first, last> __data;
//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.
//The operators are defined in the macro itself instead of a class for
//technical reasons. If someone determines a way to move them to one, please
//do so.
#define EndSubBitUnion(name) \
}; \
inline operator const __DataType () \
{ return __data; } \
\
inline const __DataType operator = (const __DataType & _data) \
{ __data = _data; } \
} name;
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SubBitUnion(name, first, last) \
__SubBitUnion(Bitfield, first, last, name)
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SignedSubBitUnion(name, first, last) \
__SubBitUnion(SignedBitfield, first, last, name)
//Use this to define an arbitrary type overlayed with bitfields.
#define BitUnion(type, name) __BitUnion(type, name)
//Use this to define conveniently sized values overlayed with bitfields.
#define BitUnion64(name) __BitUnion(uint64_t, name)
#define BitUnion32(name) __BitUnion(uint32_t, name)
#define BitUnion16(name) __BitUnion(uint16_t, name)
#define BitUnion8(name) __BitUnion(uint8_t, name)
#endif // __BASE_BITFIELD_HH__

306
src/base/bitunion.hh Normal file
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@ -0,0 +1,306 @@
/*
* Copyright (c) 2003-2005 The Regents of The University of Michigan
* 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: Gabe Black
*/
#ifndef __BASE_BITUNION_HH__
#define __BASE_BITUNION_HH__
#include <inttypes.h>
#include "base/bitfield.hh"
// The following implements the BitUnion system of defining bitfields
//on top of an underlying class. This is done through the pervasive use of
//both named and unnamed unions which all contain the same actual storage.
//Since they're unioned with each other, all of these storage locations
//overlap. This allows all of the bitfields to manipulate the same data
//without having to have access to each other. More details are provided with
//the individual components.
//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).
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
{
protected:
Data __data;
//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
{
return bits(__data, first, last);
}
//Similar to the above, but for settings bits with replaceBits.
inline void
setBits(int first, int last, uint64_t val)
{
replaceBits(__data, 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
{
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>
{
public:
operator uint64_t () const
{
return this->getBits(first, last);
}
uint64_t
operator=(const uint64_t _data)
{
this->setBits(first, last, _data);
return _data;
}
};
//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>
{
private:
uint64_t
operator=(const uint64_t _data);
};
//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=;
};
};
//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
{
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;
}
};
//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 SignedBitfieldRO : public SignedBitfield<first, last>
{
private:
int64_t
operator=(const int64_t _data);
};
//Similar to the above, but only allows writing.
template<int first, int last=first>
class SignedBitfieldWO : public SignedBitfield<first, last>
{
private:
operator int64_t () const;
public:
int64_t operator=(const int64_t _data)
{
*((SignedBitfield<first, last> *)this) = _data;
return _data;
}
};
};
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>
class BitUnionOperators : public Base
{
public:
operator Type () const
{
return Base::__data;
}
Type
operator=(const Type & _data)
{
Base::__data = _data;
return _data;
}
bool
operator<(const Base & base) const
{
return Base::__data < base.__data;
}
bool
operator==(const Base & base) const
{
return Base::__data == base.__data;
}
};
}
//This macro is a backend for other macros that specialize it slightly.
//First, it creates/extends a namespace "BitfieldUnderlyingClasses" and
//sticks the class which has the actual union in it, which
//BitfieldOperators above inherits from. Putting these classes in a special
//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
//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
//bitfields which are defined in the union, creating shared storage with no
//overhead.
#define __BitUnion(type, name) \
namespace BitfieldUnderlyingClasses \
{ \
class name; \
} \
class BitfieldUnderlyingClasses::name : \
public BitfieldBackend::BitfieldTypes<type> \
{ \
public: \
typedef type __DataType; \
union { \
type __data;\
//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
//class inheriting from the class and union just defined, which completes
//building up the type for the user.
#define EndBitUnion(name) \
}; \
}; \
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
//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> \
{ \
public: \
union { \
fieldType<first, last> __data;
//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.
//The operators are defined in the macro itself instead of a class for
//technical reasons. If someone determines a way to move them to one, please
//do so.
#define EndSubBitUnion(name) \
}; \
inline operator const __DataType () \
{ return __data; } \
\
inline const __DataType operator = (const __DataType & _data) \
{ __data = _data; } \
} name;
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SubBitUnion(name, first, last) \
__SubBitUnion(Bitfield, first, last, name)
//Regular bitfields
//These define macros for read/write regular bitfield based subbitfields.
#define SignedSubBitUnion(name, first, last) \
__SubBitUnion(SignedBitfield, first, last, name)
//Use this to define an arbitrary type overlayed with bitfields.
#define BitUnion(type, name) __BitUnion(type, name)
//Use this to define conveniently sized values overlayed with bitfields.
#define BitUnion64(name) __BitUnion(uint64_t, name)
#define BitUnion32(name) __BitUnion(uint32_t, name)
#define BitUnion16(name) __BitUnion(uint16_t, name)
#define BitUnion8(name) __BitUnion(uint8_t, name)
#endif // __BASE_BITUNION_HH__