Quality of designs from an automatic logic generator (ALERT)

• Authors: Theodore D. Friedman;Sih-Chin Yang
• Venue: DAC '70 Proceedings of the 7th Design Automation Workshop
• Year: 1970

Automation of the design of computer logic has evoked wide-spread interest and activity. Nevertheless, detailed comparisons of automatically generated logic and manually prepared logic have not been made available. The ALERT program is a logic generator which accepts as input a summary description of a new computer in a high-level language, and from this it compiles logic designs to carry out the functions specified. This paper examines the quality of logic generated by the ALERT system. The specifications of several computers have been processed through the ALERT system. This report discusses the most comprehensive design processed, the central processor of the IBM 1800 computer. The 1800 had been designed by conventional manual techniques prior to this study, and its logic schematics were, therefore, available for comparison with the logic generated by ALERT. It was found that the automatically produced circuitry required 160% more components than used in the corresponding parts of the actual computer. Reasons for this discrepancy are considered, and methods are described which are expected to reduce the discrepancy between automatically generated designs and manual designs. The study indicates that automatic generation of computer logic and circuitry from high-level system descriptions offers a practical and viable alternative to traditional methods of logic design. Within the limits of the study, the automatically prepared design was found to be correct, functional, and manufacturable.