Patent US 5,239,663

Apparatus is described for evaluating an expression comprised of a plurality of subexpressions, each including at least one argument of a corresponding input value. The evaluating apparatus comprises a plurality of resolution modules disposed in an ordered sequence. Each resolution module corresponds to one of the input values and is adapted to perform at least one given function on its input value. Each of a plurality of logical groups of the resolution modules includes at least one resolution module and is related to a corresponding one of the subexpressions. Each resolution module comprises a first input for receiving its input value, a first output, a second input adapted to be coupled to the first output of a previous resolution module in the ordered sequence, a third input for receiving a signal indicative of the position of the input value within its subexpression, and a second output for selectively providing a final value of the subexpression dependent upon the position information signal, the input value, and the first output of the previous resolution module. Each resolution module also includes a logic circuit for operating in accordance with its given function on its input value and the first output of a previous resolution module to provide at its first output a current subexpression value. The position signal determines which of the resolution modules within a logical group is its last resolution module. The last resolution module applies at its first output a nonsignificant signal with respect to the next resolution module of the adjacent logical group of resolution modules.