Technique for Invoking Special Microcode Hardware-Assisted Function As a Service Aid
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Special routines that occur during initialization or recovery sequences, such as those that validate storage keys, purge caches and invalidate the directory lookaside buffer (DLAT), can be used outside of their normal use. Any control or hardware-assisted function can be used in creating microcode diagnostic routines that stress the machine so long as their execution does not cause any integrity problem. This is done with the use of invalid op codes, by branching to the microcode routine for the special function whenever a specified invalid op code is decoded. This provides the ability to concentrate these special functions in one program or diagnostic routine. The saving is in the elimination of the time consumed by IPL or power-on resetting sequences that occur when these special functions are normally invoked.