Bitwise implementation mechanism for a circuit design synthesis procedure

Abstract

In a procedure for synthesizing circuit designs, a SYNTHESIZE command in a consequence portion of a rule can be used to control the creation of bit-level instances from a description of a more abstract instance whose interface consists of multi-bit signals. The `synthesize` command has a form that identifies multibit signal/part objects in the data base relative to the current multi-bit instance, which are then synthesized over the range of most-significant to least significant bit. A collection of rules, called macrorules are enclosed within a `synthesize` command. An iteration controlled by 'current bit', ranging from least significant to most significant bit, ensues. At each step of the iteration, all macrorules are tested and applied if they are `true`. The macrorules can query whether the current bit is a function of the least or most significant bits. The macrorules can also establish connectivity to any signal bit relative to the current, the least significant or the most significant bit. Signals which represent numeric constants, are converted to the correct binary value for each bit of the bitwise synthesis. During this process, new signal names with bit subscripts are generated, if needed, and connections are made so that the resulting data base represents an electrically connected circuit.