Describe simulation of BP and BTB pipelines

[pavelkryukov]

We have a detailed description of BPU model, but it does not cover interaction with pipeline and process of flush.

New manual should answer these questions:

1. What are the 3 branch types?
2. What prediction should be made for the each of branch type?
3. What are the stages where prediction may be verified?
4. What is performed on branch misprediction?
5. What signals are distributed between stages to maintain the behavior?

[pavelkryukov]

@beanefit Disclaimer: you have 10 points already in this term. Any additional work will not affect your your course result (however, in the contribution score table all the points will be mentioned) .

[beanefit]

@beanefit Disclaimer: you have 10 points already in this term. Any additional work will not affect your your course result (however, in the contribution score table all the points will be mentioned) .

Thank you for the disclaimer. I just want to try myself in explaining some things to others, that's why I've assigned this issue.

[beanefit]

I've attempted to explain some basics of this simulation. Here it is.

[pavelkryukov]

Your manual requires a lot of pictures,

[pavelkryukov]

https://github.com/MIPT-ILab/mipt-mips/wiki/github-markdown-bkms#how-to-upload-a-picture

[pavelkryukov]

1. Have you read this: https://github.com/MIPT-ILab/mipt-mips/wiki/How-to-write-Wiki-manuals ?
2. It's very hard to read about all 3 types of branchex mixed. Can we process type by type?
   • Each section for each branch should start with the topology — 5 stages and wires used.
   • Then you put examples for each case: correct prediction, incorrect prediction etc.
3. What do these pentagons mean?
4. What should I understand from that picture? https://github.com/MIPT-ILab/mipt-mips/wiki/Interaction-between-BPU-and-pipeline-pictures/pic_1.png
5. You should not copy-paste C++ code — if we wanted to read C++ code, we would go to the repository. You should explain what it does and, more imporantly, why it does it.
6. Introduction section does not introduce to anywhere — it just says that BPU is a BPU. There is no logical connection to the next paragraph!
7. https://github.com/MIPT-ILab/mipt-mips/wiki/Interaction-between-BPU-and-pipeline#fetch-stage — why should I know all that information? Shall it be actual if we add one more source of target?

[beanefit]

I've begun refactoring. Will finish this evening. Could you please have a quick look at it just to notice some general mistakes?

[pavelkryukov]

I've begun refactoring. Will finish this evening.

Please do not rush — write permission won't disappear after the deadline.

[beanefit]

I've begun refactoring. Will finish this evening.

Please do not rush — write permission won't disappear after the deadline.

No, I mean I'll continue working on it this evening.