Flute an Expert Floor Planner for Full-Custom VLSI Design

Flute is a heuristic floorplanner that operates as part of Cadre, a system of cooperating expert agents for converting a hierarchical structural description into full-custom VLSI layout. Flute is modeled on the human floorplanning process and uses a mixture of rule-based programming, state control, and algorithmic operators. Initially, a topological plan is generated by placing modules on a grid graph. From this plan, a constraint graph is prepared. This graph is solved to add geometric size and placement information to the floorplan. Though Flute handles a fairly small number of submodules at a time, it can construct a floorplan of complex VLSI layout using a hierarchical structure of ICs. Flute is implemented in Zeta-lisp on Symbolics Lisp machines.