A memory bank that implements reads and writes using a hash table. More...
#include <memstate.hh>
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... | |
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 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
References alignshift, collideskip, and underlie.
Member Function Documentation
◆ find()
|
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.
References address, alignshift, collideskip, MemoryBank::find(), underlie, and value.
◆ insert()
|
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.
References address, alignshift, collideskip, and value.
The documentation for this class was generated from the following files:
- memstate.hh
- memstate.cc
