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

#include <memstate.hh>

Inheritance diagram for ghidra::MemoryHashOverlay:

Collaboration diagram for ghidra::MemoryHashOverlay:

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

Public Member Functions inherited from ghidra::MemoryBank
	MemoryBank (AddrSpace *spc, int4 ws, int4 ps)
	Generic constructor for a memory bank.

int4	getWordSize (void) const
	Get the number of bytes in a word for this memory bank.

int4	getPageSize (void) const
	Get the number of bytes in a page for this memory bank.

AddrSpace *	getSpace (void) const
	Get the address space associated with this memory bank.

void	setValue (uintb offset, int4 size, uintb val)
	Set the value of a (small) range of bytes.

uintb	getValue (uintb offset, int4 size) const
	Retrieve the value encoded in a (small) range of bytes.

void	setChunk (uintb offset, int4 size, const uint1 *val)
	Set values of an arbitrary sequence of bytes.

void	getChunk (uintb offset, int4 size, uint1 *res) const
	Retrieve an arbitrary sequence of bytes.

Protected Member Functions
virtual void	insert (uintb addr, uintb val)
	Overridden aligned word insert.

virtual uintb	find (uintb addr) const
	Overridden aligned word find.

Protected Member Functions inherited from ghidra::MemoryBank
virtual void	getPage (uintb addr, uint1 *res, int4 skip, int4 size) const
	Retrieve data from a memory page.

virtual void	setPage (uintb addr, const uint1 *val, int4 skip, int4 size)
	Write data into a memory page.

Private Attributes
MemoryBank *	underlie
	Underlying memory bank.

int4	alignshift
	How many LSBs are thrown away from address when doing hash table lookup.

uintb	collideskip
	How many slots to skip after a hashtable collision.

vector< uintb >	address
	The hashtable addresses.

vector< uintb >	value
	The hashtable values.

Additional Inherited Members
Static Public Member Functions inherited from ghidra::MemoryBank
static uintb	constructValue (const uint1 *ptr, int4 size, bool bigendian)
	Decode bytes to value.

static void	deconstructValue (uint1 *ptr, uintb val, int4 size, bool bigendian)
	Encode value to bytes.

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()

ghidra::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

References alignshift, collideskip, and underlie.

Member Function Documentation

◆ find()

uintb ghidra::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