Systems and methods for replacing data retrieved from memory
AssigneeSemiconductor Components Industries, LLC
InventorPeter Michael Hall
Life of this patent
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Abstract
An electronic system such as an imaging system may include processing circuitry and memory circuitry. Data replacement circuitry may be interposed between the processing circuitry and the memory circuitry. In some implementations, the memory circuitry may be a read-only memory, and data replacement circuitry may be used to selectively replace executable firmware instructions stored on the read-only memory. The selective replacement operations may be based on an address that processing circuitry provides to access the memory circuitry. The data replacement circuitry may be implemented separately from the processing circuitry and the memory circuitry and may include a comparator block, registers, and switching circuitry.
Claims20
An imaging system comprising:
- processing circuitry;
- memory circuitry operable to receive an address in the memory circuitry and output data stored at the address;
- and
- data replacement circuitry interposed between the processing circuitry and the memory circuitry, wherein the data replacement circuitry is operable to receive the output data and the address, wherein the data replacement circuitry comprises:
- a set of comparators, each operable to perform a corresponding comparison operation using the address,
- a replacement instruction storage circuit that stores a same hard-coded instruction for the set of comparators, wherein the data replacement circuitry is configured to output the same hard-coded instruction instead of the output data in response to a match resulting from any of the corresponding comparison operations at any comparator in the set of comparators, and
- a register configured to provide an identifier of a comparator, with which the match is associated, to the processing circuitry.
A method of patching data stored in memory circuitry, the method comprising:
- receiving an address at which corresponding data is stored in the memory circuitry and with which processing circuitry is configured to access the corresponding data;
- determining whether the address matches a set of reference addresses at which patching is required;
- in response to determining that the address matches any reference address in the set of reference addresses, sending a same instruction to the processing circuitry that causes the processing circuitry to enter an exception state;
- providing, to the processing circuitry, identifying information indicative of a given reference address that matched the address;
- and
- while the processing circuitry is in the exception state, identifying a case-specific replacement instruction specifically for patching the corresponding data at the address.
An electronic system comprising:
- processing circuitry;
- a read-only memory;
- and
- data replacement circuitry coupled between the processing circuitry and the read-only memory, the data replacement circuitry comprising:
- a comparator block that includes a plurality of comparators,
- a register coupled to the comparator block and configured to provide information identifying a given comparator in the plurality of comparators to the processing circuitry,
- switching circuitry having a control input coupled to the register and having a first data input coupled to the read-only memory and a second data input, and
- a replacement instruction storage circuit that is coupled to the second data input of the switching circuitry and that is configured to store a hard-coded instruction shared by the plurality of comparators, wherein the switching circuitry is configured to pass the hard-coded instruction to an output of the switching circuitry in response to a match at any enabled comparators in the comparator block.
Dependencies are inferred from the claim text.