Reliable Error Indication Under Programmed Testing
Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13
Programmed processors have the capability of self-diagnosing or testing of one processor by another. During such programmed testing, however, the program can be branched to an unexpected or unknown location or become stuck in a loop, precluding an indication of where the error or malfunction occurred. For example, when one processor (PUT) is being tested by another processor (PPT), the PUT has control transferred to it by the PPT but may become enmeshed in a loop or some other malfunction which prevents the PUT from successfully completing a particular test and returning control to the PPT. Another example is a processor performing a self test in which an interrupt or branch-and-link instruction test is not successfully completed so that the program control is lost and no error indication can be made.