Research note: microcode bit optimization is NP-hard
ACM SIGMICRO Newsletter
An Approach to the Optimal Specification of Read-Only Memories in Microprogrammed Digital Computers
IEEE Transactions on Computers
An Approach to Organizing Microinstructions which Minimizes the Width of Control Store Words
IEEE Transactions on Computers
On the Minimization of Wordwidth in the Control Memory of a Microprogrammed Digital Computer
IEEE Transactions on Computers
Microprogram Optimization: A Survey
IEEE Transactions on Computers
Toward Optimization of Horizontal Microprograms
IEEE Transactions on Computers
On the Minimization of READ-ONLY Memories in Microprogrammed Digital Computers
IEEE Transactions on Computers
On the Minimization of the Control Store in Microprogrammed Computers
IEEE Transactions on Computers
Bit steering in the minimization of control memory in microprogrammed digital computers
IEEE Transactions on Computers
Control memory word width optimization using multiple-valued circuits
IEEE Transactions on Computers
Microcode Compression Using Structured-Constrained Clustering
International Journal of Parallel Programming
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This paper describes an algorithm for minimizing the storage required of a Read Only Memory that is going to be used as the control element for a digital machine. The technique is based upon the fact that not all sub-commands are required in all words so that bits of the memory may be time shared between subcommands. The algorithm provides a means for determining what sub-commands should share a common set of bits. The algorithm is essentially one of exhaustive evaluation but it is one that directs you toward the solution rather than one which randomly tries all possible solutions and chooses the best. In addition certain bounds on the "size" of the solution are derived and these in turn eliminate a large segment of the possible solution set from consideration. Finally, the algorithm is quite iterative and as such lends itself readily to implementation of a digital machine.