ChatCPU: An Agile CPU Design and Verification Platform with LLM

The increasing complexity of semiconductor designs necessitates agile hardware development methodologies to keep pace with rapid technological advancements. Following this trend, the Large Language Models (LLMs) emerge as a potential solution, providing new opportunities in hardware design automation. However, existing LLMs exhibit challenges in HDL design and verification, especially for complicated hardware systems. Addressing this need, we introduce ChatCPU, the first end-to-end agile hardware design and verification platform with LLM. ChatCPU streamlines the ASIC design and verification process, guiding it from initial specifications to the final RTL implementations with enhanced design agility. Incorporating the LLM fine-tuning and the processor description language design for CPU design automation, ChatCPU significantly enhances the hardware design capability using LLM. Utilizing ChatCPU, we developed a 6-stage in-order RISC-V CPU prototype, achieving successful tape-out using SkyWater 130nm MPW project with Efabless, which is currently the largest CPU design generated by LLM. Our results demonstrate a remarkable improvement in CPU design efficiency, accelerating the design iteration process by an average of 3.81X, and peaking at 12X and 9.33X in HDL implementations and verification stages, respectively. The ChatCPU also enhances the design capability of LLM by 2.63X as compared to base LLama2. These advancements in ChatCPU represent a significant milestone in LLM-driven ASIC design and optimization.