MemoryBank Class Reference

Memory storage/state for a single AddressSpace. More...

#include <memstate.hh>

Inheritance diagram for MemoryBank:

Public Member Functions
	MemoryBank (AddrSpace *spc, int4 ws, int4 ps)
	Generic constructor for a memory bank. More...
int4	getWordSize (void) const
	Get the number of bytes in a word for this memory bank. More...
int4	getPageSize (void) const
	Get the number of bytes in a page for this memory bank. More...
AddrSpace *	getSpace (void) const
	Get the address space associated with this memory bank. More...
void	setValue (uintb offset, int4 size, uintb val)
	Set the value of a (small) range of bytes. More...
uintb	getValue (uintb offset, int4 size) const
	Retrieve the value encoded in a (small) range of bytes. More...
void	setChunk (uintb offset, int4 size, const uint1 *val)
	Set values of an arbitrary sequence of bytes. More...
void	getChunk (uintb offset, int4 size, uint1 *res) const
	Retrieve an arbitrary sequence of bytes. More...

Static Public Member Functions
static uintb	constructValue (const uint1 *ptr, int4 size, bool bigendian)
	Decode bytes to value. More...
static void	deconstructValue (uint1 *ptr, uintb val, int4 size, bool bigendian)
	Encode value to bytes. More...

Protected Member Functions
virtual void	insert (uintb addr, uintb val)=0
	Insert a word in memory bank at an aligned location.
virtual uintb	find (uintb addr) const =0
	Retrieve a word from memory bank at an aligned location.
virtual void	getPage (uintb addr, uint1 *res, int4 skip, int4 size) const
	Retrieve data from a memory page. More...
virtual void	setPage (uintb addr, const uint1 *val, int4 skip, int4 size)
	Write data into a memory page. More...

Friends
class	MemoryPageOverlay
class	MemoryHashOverlay

Detailed Description

Memory storage/state for a single AddressSpace.

Class for setting and getting memory values within a space The basic API is to get/set arrays of byte values via offset within the space. Helper functions getValue and setValue easily retrieve/store integers of various sizes from memory, using the endianness encoding specified by the space. Accesses through the public interface, are automatically broken down into word accesses, through the private insert/find methods, and page accesses through getPage/setPage. So these are the virtual methods that need to be overridden in the derived classes.

Constructor & Destructor Documentation

MemoryBank()

MemoryBank::MemoryBank	(	AddrSpace *	spc,
		int4	ws,
		int4	ps
	)

Generic constructor for a memory bank.

A MemoryBank must be associated with a specific address space, have a preferred or natural wordsize and a natural pagesize. Both the wordsize and pagesize must be a power of 2.

Parameters

spc	is the associated address space
ws	is the number of bytes in the preferred wordsize
ps	is the number of bytes in a page

Member Function Documentation

constructValue()

uintb MemoryBank::constructValue ( const uint1 *  ptr, int4  size, bool  bigendian  )

static

Decode bytes to value.

This is a static convenience routine for decoding a value from a sequence of bytes depending on the desired endianness

Parameters

ptr	is the pointer to the bytes to decode
size	is the number of bytes
bigendian	is true if the bytes are encoded in big endian form

Returns

the decoded value

deconstructValue()

void MemoryBank::deconstructValue ( uint1 *  ptr, uintb  val, int4  size, bool  bigendian  )

static

Encode value to bytes.

This is a static convenience routine for encoding bytes from a given value, depending on the desired endianness

Parameters

ptr	is a pointer to the location to write the encoded bytes
val	is the value to be encoded
size	is the number of bytes to encode
bigendian	is true if a big endian encoding is desired

getChunk()

void MemoryBank::getChunk	(	uintb	offset,
		int4	size,
		uint1 *	res
	)		const

Retrieve an arbitrary sequence of bytes.

This is the most general method for reading a sequence of bytes from the memory bank. There is no restriction on the offset or the number of bytes to read, except that the range must be contained in the address space.

Parameters

offset	is the start of the byte range to read
size	is the number of bytes to read
res	is a pointer to where the retrieved bytes should be stored

getPage()

void MemoryBank::getPage ( uintb  addr, uint1 *  res, int4  skip, int4  size  ) const

protectedvirtual

Retrieve data from a memory page.

This routine only retrieves data from a single page in the memory bank. Bytes need not be retrieved from the exact start of a page, but all bytes must come from one page. A page is a fixed number of bytes, and the address of a page is always aligned based on that number of bytes. This routine may be overridden for a page based implementation of the MemoryBank. The default implementation retrieves the page as aligned words using the find method.

Parameters

addr	is the aligned offset of the desired page
res	is a pointer to where fetched data should be written
skip	is the offset into the page to get the bytes from
size	is the number of bytes to retrieve

Reimplemented in MemoryPageOverlay, and MemoryImage.

getPageSize()

int4 MemoryBank::getPageSize ( void  ) const

inline

Get the number of bytes in a page for this memory bank.

A MemoryBank is instantiated with a natural page size. Requests for large chunks of data may be broken down into units of this size.

Returns

the number of bytes in a page.

getSpace()

AddrSpace * MemoryBank::getSpace ( void  ) const

inline

Get the address space associated with this memory bank.

A MemoryBank is a contiguous sequence of bytes associated with a particular address space.

Returns

the AddressSpace associated with this bank.

getValue()

uintb MemoryBank::getValue	(	uintb	offset,
		int4	size
	)		const

Retrieve the value encoded in a (small) range of bytes.

This routine gets the value from a range of bytes at an arbitrary address. It takes into account the endianness of the underlying space when decoding the value. The value is constructed by making one or more aligned word queries, using the find method. The desired value may span multiple words and is reconstructed properly.

Parameters

offset	is the start of the byte range encoding the value
size	is the number of bytes in the range

Returns

the decoded value

getWordSize()

int4 MemoryBank::getWordSize ( void  ) const

inline

Get the number of bytes in a word for this memory bank.

A MemoryBank is instantiated with a natural word size. Requests for arbitrary byte ranges may be broken down into units of this size.

Returns

the number of bytes in a word.

setChunk()

void MemoryBank::setChunk	(	uintb	offset,
		int4	size,
		const uint1 *	val
	)

Set values of an arbitrary sequence of bytes.

This the most general method for writing a sequence of bytes into the memory bank. There is no restriction on the offset to write to or the number of bytes to be written, except that the range must be contained in the address space.

Parameters

offset	is the start of the byte range to be written
size	is the number of bytes to write
val	is a pointer to the sequence of bytes to be written into the bank

setPage()

void MemoryBank::setPage ( uintb  addr, const uint1 *  val, int4  skip, int4  size  )

protectedvirtual

Write data into a memory page.

This routine writes data only to a single page of the memory bank. Bytes need not be written to the exact start of the page, but all bytes must be written to only one page when using this routine. A page is a fixed number of bytes, and the address of a page is always aligned based on this size. This routine may be overridden for a page based implementation of the MemoryBank. The default implementation writes the page as a sequence of aligned words, using the insert method.

Parameters

addr	is the aligned offset of the desired page
val	is a pointer to the bytes to be written into the page
skip	is the offset into the page where bytes will be written
size	is the number of bytes to be written

Reimplemented in MemoryPageOverlay.

setValue()

void MemoryBank::setValue	(	uintb	offset,
		int4	size,
		uintb	val
	)

Set the value of a (small) range of bytes.

This routine is used to set a single value in the memory bank at an arbitrary address It takes into account the endianness of the associated address space when encoding the value as bytes in the bank. The value is broken up into aligned pieces of wordsize and the actual write is performed with the insert routine. If only parts of aligned words are written to, then the remaining parts are filled in with the original value, via the find routine.

Parameters

offset	is the start of the byte range to write
size	is the number of bytes in the range to write
val	is the value to be written

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The documentation for this class was generated from the following files:

• memstate.hh
• memstate.cc