This is my code and design documents for the SNU Computer Organization (Spring, 2019) course project. This repository only contains the code I wrote myself, thus excluding the TestBench or Memory module. I am opening this repository publicly so as to provide a reference inplementation for various types of CPUs. Please refer to the LICENSE if you want to utilize code from this repository.

Generally, features of the CPU stack up as its index increases. For example, 06. Tournament Prediction CPU also has data-forwarding, which was first introduced in 04. Data Forwarding CPU. Each CPU implementation folder contains verilog code and its design document. The design document (design.pdf) contains descriptions, logics, and performance analyses of the CPU.

• 01. Single-cycle CPU: A single cycle CPU that has an IPC of 1.
• 02. Multi-cycle CPU: A multi cycle CPU that has an IPC of 1.
• 03. Pipelined CPU: A 5-stage pipelined CPU. Everything after this has this as its base architecture.
• 04. Data Forwarding CPU: Data forwarding from the ALU result port to previous pipeline stages.
• 05. 2-Sat Branch Prediction CPU: Branch prediction with a BTB with 2-bit saturation counter. Previous CPUs always predicted not-taken.
• 06. Tournament Prediction CPU: The DEC Alpha 21264 tournament branch predictor is implemented (without the line-and-way predictor).
• 07. 2-cycle Memory CPU: A slightly more realistic CPU that communicates with a slow memory. The variable LATENCY (default 2) can be modified to change the latency of the memory.
• 08. Harvard Arch Cached CPU: An instruction cache and a data cache is implemented. The instruction cache prefetches instructions from the next block to further reduce fetch latency.
• 09. Simple DMA CPU: A simple DMA module and an its required interrupt mechanism is implemented.
• 10. Cycle-stealing DMA CPU: DMA operations are interleaved with instructions that access the data cache to minimize pipeline stall.