A methodology for correct-by-construction latency insensitive design

In deep sub-micron (DSM) designs, performance will depend critically on the latency of long wires. We propose a new synthesis methodology for synchronous systems that makes the design functionally insensitive to the latency of long wires. Given a synchronous specification of a design, we generate a functionally equivalent synchronous implementation that can tolerate arbitrary communication latency between latches. By using latches we can break a long wire in short segments which can be traversed while meeting a single clock cycle constraint. The overall goal is to obtain a design that is robust with respect to delays of long wires, in a shorter time by reducing the multiple iterations between logical and physical design, and with performance that is optimized with respect to the speed of the single components of the design. We describe the details of the proposed methodology as well as report on the latency insensitive design of PDLX, an out-of-order microprocessor with speculative-execution.