User:Don Hooper/sandbox

VAX 9000 LOGIC SYNTHESIS

SID

SID (System for Integral Design) was a rule-based system used for the generation of the VAX 9000 logic design. SID was developed using the programming language LISP. Using SID, the VAX 9000 design was first entered with a choice of high-level behavioral computer languages or CAD drawings, using operators such as "add" or "multiply." The designer could then specify constraint parameters including cycle time and area for top-level blocks of logic, such as ALU. Being an AI expert system, SID rules were written by expert logic designers, and as such the rules mimicked the decisions of a computer hardware engineer. At the boolean logic level SID used a combination of timing/area optimization rules, truth table rules and DeMorgan's Theorems rules for conversions. The SID software program would pass the design through rule group levels descending in greater detail, finally ending with the wiring connection of the logic gates. It would continue to iterate the design using the constraining parameters, until no more rules fired. in addition, SID performed cycle time verification and logic accuracy verification. The lowest level rule-base improved VAX 9000 performance (cycle time) by 10%. The resulting output was ready for chip placement on the circuit board. The SID software architecture is described in .