Dual Data Checking With Masked Data Fetch and Modify Device
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
The ability to check data in a masked data fetch and modifying device is provided when the modifying data type is different from that of the fetched data. In a masked data fetch and modifying device, loading of fetch data is inhibited by a mask bit where modify data is placed. The mask bit is also used to identify the type of data. In the figure, when a masked data fetch with a modifying device is used in a computer system, the data contained in the register under consideration may contain modifying data, fetched data, or both data types. The modifying data may originate from an internal path in the CPU and will usually contain parity. The fetch data may originate from an external memory device and will usually contain a corresponding error correction code (ECC) bit.