FREESS: A Web-Based Educational Simulator for a RISC-V-Inspired Superscalar Processor with Tomasulo-Style Dynamic Scheduling
This simulator provides an educational tool for students learning advanced computer architecture, specifically instruction-level parallelism and superscalar processor design.
This paper presents FREESS, an open-source web-based simulator for a RISC-V-inspired superscalar processor with Tomasulo-style dynamic scheduling. It provides a cycle-by-cycle view of instruction-level parallelism, allowing users to observe hardware state evolution and compare different superscalar organizations by adjusting runtime parameters.
FREESS (Free Educational Superscalar Simulator) is an open-source teaching environment for instruction-level parallelism in a RISC-V-inspired superscalar processor. It provides a compact, cycle-by-cycle view of register renaming, issue, execution, write-back, commit, and memory ordering in a Tomasulo-style machine. The simulator exposes the register map, free pool, instruction window, reorder buffer, and load/store queues in one textual representation, so the evolution of the hardware state can be followed on screen and reproduced on paper. Runtime parameters such as issue width, queue sizes, and functional-unit latencies can be changed easily, enabling direct comparison among alternative superscalar organizations. The tool has supported Advanced Computer Architecture teaching for about fifteen years and is publicly available on GitHub.