US 2004/0205318 A1 · Remapping of data access requests

Abstract

A method and data processing apparatus for remapping selected data access requests issued by a processor for accessing data items stored on a ROM. The method comprises the following steps: storing at least one replacement data item corresponding to at least one data item and different to said at least one data item in a portion of a RAM memory block, said RAM memory block being accessible by said processor, and said portion having been defined for storage of said at least one replacement data item; intercepting a data access request from said processor to said ROM; comparing at least a portion of an address of said intercepted data access request with a stored at least one identifier, said stored at least one identifier identifying an address of at least one data item stored on said ROM, and depending on said comparison either: remapping said data access request to said RAM memory block, such that a replacement data item stored on said memory block is accessed if said comparison indicates said at least a portion of an address to correspond to an address identified by said at least one identifier; or if said comparison indicates said at least a portion of an address not to be an address identified by said at least one stored identifier accessing a data item located at a position corresponding to said address on said ROM.

Claims31

Dependent claims

A method for remapping selected data access requests issued by a processor for accessing data items stored on a ROM, said method comprising the following steps:

(ii) storing at least one replacement data item corresponding to at least one data item and different to said at least one data item in a portion of a RAM memory block, said RAM memory block being accessible by said processor, and said portion having been defined for storage of said at least one replacement data item;
(iii) intercepting a data access request from said processor to said ROM;
(iv) comparing at least a portion of an address of said intercepted data access request with a stored at least one identifier, said stored at least one identifier identifying an address of at least one data item stored on said ROM, and depending on said comparison either:
(va) remapping said data access request to said RAM memory block, such that a replacement data item stored on said memory block is accessed if said comparison indicates said at least a portion of an address to correspond to an address identified by said at least one identifier;
or
(vb) if said comparison indicates said at least a portion of an address not to be an address identified by said at least one stored identifier accessing a data item located at a position corresponding to said address on said ROM.

3 more elements

A data processing apparatus comprising:

a processor;
a read only memory for storing data items, said read only memory being accessible by said processor;
a memory block of RAM accessible by said processor and operable to store at least one replacement data item corresponding to at least one data item stored in said ROM and different to said at least one data item in a portion of a RAM memory block, said portion having been defined for storage of said at least one replacement data item;
a data request interceptor comprising a data store and a comparator;
wherein
said data store is operable to store at least one identifier, said at least one identifier identifying an address of said at least one data item stored on said ROM;
and
said data request interceptor is operable to intercept data access requests issued by said processor to said ROM and using said comparator to compare at least a portion of an address of said intercepted data access request with said stored at least one identifier and depending on said comparison said data request interceptor is operable to either:
access data located at a position corresponding to said intercepted data access request address on said ROM if said comparison indicates said at least a portion of an address not to be an address identified by said at least one stored identifier;
or to remap said data access request to access said at least one replacement data item if said comparison indicates said at least a portion of an address to be an address identified by said at least one stored identifier.

7 more elements

Dependencies are inferred from the claim text.

Remapping of data access requests

Life of this patent

Remapping of data access requests

Life of this patent

Abstract

Claims31