MemoryHashOverlay Class Reference

A memory bank that implements reads and writes using a hash table. More...

#include <memstate.hh>

Inheritance diagram for MemoryHashOverlay:

Collaboration diagram for MemoryHashOverlay:

Public Member Functions
	MemoryHashOverlay (AddrSpace *spc, int4 ws, int4 ps, int4 hashsize, MemoryBank *ul)
	Constructor for hash overlay. More...
Public Member Functions inherited from MemoryBank
	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...

Protected Member Functions
virtual void	insert (uintb addr, uintb val)
	Overridden aligned word insert. More...
virtual uintb	find (uintb addr) const
	Overridden aligned word find. More...
Protected Member Functions inherited from MemoryBank
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...

Additional Inherited Members
Static Public Member Functions inherited from MemoryBank
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...

Detailed Description

A memory bank that implements reads and writes using a hash table.

The initial state of the bank is taken from an underlying memory bank or is all zero, if this bank is initialized with a null pointer. This implementation will not be very efficient for accessing entire pages.

Constructor & Destructor Documentation

MemoryHashOverlay()

MemoryHashOverlay::MemoryHashOverlay	(	AddrSpace *	spc,
		int4	ws,
		int4	ps,
		int4	hashsize,
		MemoryBank *	ul
	)

Constructor for hash overlay.

A MemoryBank implemented as a hash table needs everything associated with a generic memory bank, but the constructor also needs to know the size of the hashtable and the underlying memorybank to forward reads and writes to.

Parameters

spc	is the address space associated with the memory bank
ws	is the number of bytes in the preferred wordsize (must be power of 2)
ps	is the number of bytes in a page (must be a power of 2)
hashsize	is the maximum number of entries in the hashtable
ul	is the underlying memory bank being overlayed

Member Function Documentation

find()

uintb MemoryHashOverlay::find ( uintb  addr ) const

protectedvirtual

Overridden aligned word find.

First search for an entry in the hashtable using addr as a key. If there is no entry, forward the query to the underlying memory bank, or return 0 if there is no underlying bank

Parameters

addr	is the aligned address of the word to retrieve

Returns

the retrieved value

Implements MemoryBank.

insert()

void MemoryHashOverlay::insert ( uintb  addr, uintb  val  )

protectedvirtual

Overridden aligned word insert.

Write the value into the hashtable, using addr as a key.

Parameters

addr	is the aligned address of the word being written
val	is the value of the word to write

Implements MemoryBank.

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

• memstate.hh
• memstate.cc