ProtoCPU: Modelling an In-Order RISC-V Core in gem5

on YouTube ↗10m

" summary

ProtoCPU is a 5-stage in-order RISC-V CPU model implemented in C++ inside gem5 that targets cycle-accurate C-class processors and runs bare-metal full-system simulations. It includes a primitive UART, a Python-based ProtoViewer pipeline viewer that visualizes traces (example: cycles 232–234 show mixed compressed and uncompressed decode), and an operand-forward unit that resolves RAW hazards by stalling until writeback. Integration uses gem5’s base CPU class and exec context; limitation: gem5’s RISC-V ISA implementation lacks official guarantees.

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" chapters (11)

1. 0:00Introduction to ProtoCPU
2. 0:15Understanding Gem5
3. 1:04Developing the CPU Model
4. 2:05Simulation Workflow
5. 3:31Pipeline Implementation
6. 4:52UART and Pipeline Viewer
7. 5:24Handling Instructions
8. 6:46Hazard Management
9. 7:35Gem5 Integration
10. 8:43Merits and Limitations
11. 9:43Conclusion

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