The Lizard Core is a synthesizable RISC-V RV64IM out-of-order processor, designed in PyMTL. It is Cornell’s first full-featured RISC-V RV64IM processor, and the most sophisticated processor ever designed in PyMTL. It was designed from scratch to be modular, capable, and performant. In order to make the design modular, we pioneered two novel techniques. The first is method-based RTL design. This technique breaks the design into well-defined modules with precise interfaces, and creates a notion of methods in hardware which have clean and easy to follow handshaking semantics. The second is the use of managers which handle the interactions between units in the pipeline. While building this processor, the engineering team also developed novel methods for testing RTL designs by leveraging method-based interfaces to automatically wrap RTL modules to Python objects.

 

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The Lizard Core is a modular, synthesizable, out-of-order, RISC-V RV64IM core written in PyMTL. It can meet timing at 350 MHz in a 45 nm standard cell-based design flow.

 

You can download the Lizard core here