Abstract: A method for performing electrical acceptance tests on a sub-system including a test substrate, a microprocessor and one or more associated computer components, such as SRAM, DRAM and ROM. A pin grid array, ball grid array, line grid array or equivalent test connector system is provided that allows direct addressing of selected circuits of the microprocessor and of each associated component. The microprocessor plus substrate are first tested together. If this test is successful, the associated components are then added, preferably one at a time, and the new sub-system is tested. If a particular sub-system fails a test, the cause(s) of failure can be isolated and removed, where possible, and the modified sub-system can be retested.

Abstract: A cache memory controller and an associated method for fetching data are utilized to reduce the idle time of a central processing unit (CPU) of a computer system. Control circuitry and a plurality of cache fill status registers are provided to a cache controller to enable a data word to be fetched and returned to the CPU while a cache memory fill initiated due to a prior cache miss is still in progress. The data word is returned if the data word is stored in a main memory location which corresponds to a memory block offset of a main memory block frame currently being mapped into the cache memory. The data word is retrieved and returned to the CPU simultaneous with its writing into the cache memory, if the data word has not been written into the cache memory; otherwise, the data word is retrieved and returned to the CPU at the next dead cycle. As a result, CPU idle time due to cache read misses is reduced.