An instruction set and programming examples are described for
a Distributed Logic Memory computer organization. The computer is
designed to take advantage of the economies of very large-scale circuit
integration. In addition, the computer can grow in an orderly
way. As it grows there is increased parallelism possible so that the
amount of spare real time in a control application is not greatly reduced.
Finally, such an organization should permit stored program
control in relatively small applications where up to now control by a
conventionally organized computer has been prohibitively expensive.
The computer consists of a linear array of identical, small, sequential
machines, or cells. The structure is similar to that of the
Distributed Logic Memory originally proposed by C. Y. Lee. It was
demonstrated by J. N. Sturman that the addition of sequential logic to
each cell permits the memory to become a self-contained computing
system.
It is the purpose of this thesis to produce an application-oriented
process control computer design based on the concepts of Lee and
Sturman. It was found necessary to increase the length of the memory
word in each cell. The ability to store instructions and data in cells
is retained. Increasing the memory word length of each cell permits
an expanded instruction repertoire. The low-ordered three bits of
every memory word are arranged to identify a cell as one of eight
possible types. A program instruction includes modifier bits which
specify the types of cells on which the instruction is to operate. This
facility enhances the efficiency of programs.
The logic design of the cell is complete enough to permit estimating
gate count per cell. An analysis of the sensitivity of gate
count to changes in the instruction set is included. A program simulation
of the Distributed Logic Memory computer assisted in its development
and later permitted verification of programs written for the
computer. The existence of a compiler permitted such programs to
be written in a convenient, symbolic form.
A data multiplexer is developed as a practical application for
the Distributed Logic Memory computer structure. The necessary
data multiplexer program, which consists of about 100 instructions,
is shown
