Path-Based Scheduling for Synthesis

Abstract

In the context of synthesis, scheduling assigns operations to control steps. Operations are the atomic components used for describing behavior, for example, arithmetic and Boolean operations. They are ordered partially by data dependencies (data-flow graph) and by control constructs such as conditional branches and loops (control-flow graph). A control step usually corresponds to one state, one clock cycle, or one microprogram step. This paper presents a new, path-based scheduling algorithm. It yields solutions with the minimum number of control steps, taking into account arbitrary constraints that limit the amount of operations in each control step. The result is a finite state machine that implements the control. Although the complexity of the algorithm is proportional to the number of paths in the control-flow graph, it is shown to be practical for large examples with thousands of nodes. © 1991 IEEE