Hardware implementation of loop trace and microprogram synthesis

The modification or tuning of the microcode in a computer that utilizes a writable control store is one method whereby a program's execution time can be improved. A method for automatically performing a microcode tuning or synthesis has been developed by Drs. Karlgaard and Abd-alla and is discussed in detail in [1]. Presented is an extension of this effort which allows microcode synthesis to be performed “on-the-fly”. This is accomplished by: (1) performing the required program trace with a hardware modification, (2) eliminating the statistics generation requirement, and (3) performing the synthesizing by using a microprogram rather than software. The implementation of this technique is described in this paper.