Categories of Modules

DM and M modules. DM stands for data operation combined with memory, and M stands for memory. The DM modules provide the register transfer gating paths and combinatorial switching circuits for performing simple arithmetic and logical functions on data. The expression "lefthand side <- righthand" side indicates that the integer or Boolean vector value of the righthand side is computed, or taken as a source, and placed in the register on the lefthand side.

The D (data operation) part of the DM module carries out evaluation of the righthand side of such an expression in which an integer or Boolean vector value is computed, e.g., <- A+B, <- A-B, or <- A+1. The M (memory) part of the DM module is just the registers (e.g., A, B) that hold data between statements. The operations on memory are usually just writing (M <-) and reading (<- M). The use of bussed data transfers makes it necessary to combine data operations (D) with