README.md

COL216-Assignment2

Files included in Submission:

1. requirements.hpp
2. pipeline.hpp
3. parser.hpp
4. simulator.hpp
5. configuration.hpp
6. branchpredictor.hpp
7. branchpredictertester.cpp
8. main.cpp
9. 5stage.cpp
10. 5stage_bypass.cpp
11. 79stage.cpp
12. 79stage_bypass.cpp
13. Makefile
14. README.md
15. report.pdf

Active instructions: add, and, or, sub, mul, slt, sll, srl, bne, beq, j, addi, lw, sw.

Instructions: write the MIPS assembly code in a file and save it as input.asm. Then use the following make commands to simulate a pipeline.

1. all - to update all dependencies
2. compile - to compile and generate the executable for all the 4 simulator parts
3. run_5stage - to run the simulator for the 5-stage pipeline
4. run_5stage_bypass - to run the simulator for the 5-stage pipeline with forwarding and bypassing
5. run_79stage - to run the simulator for the 7 and 9-stage stage pipeline
6. run_79stage_bypass - to run the simulator for the 7 and 9-stage stage pipeline with forwarding and bypassing

Note: The print_table() function of pipeline can be used to make the output more human readable.

Structures:

• configuration.hpp:
  1. Configuration=> Generates the configuration parameters for the simulator based on question number.
• requirements.hpp:
  1. Command=> Defines the structure of a command.
  2. QueueNode=> A node with three integer values.
  3. UpdateQueue=> A queue to keep track of update history in memory and register file.
  4. Registerfile=> Defines a register file and also takes over the functionality of latches.
  5. Runtimedata=> Stores the start and endtime of each stage of an instruction.
• parser.hpp:
  1. Parser=> Parses the input file and converts each instruction to an object of the Command struct according to configuration parameters.
• pipeline.hpp:
  1. Pipeline=> Defines the structure of a general pipeline. An object of it can be made by specifing the type of pipeline and can be used to run instructions.
• simulator.hpp:
  1. Simulator=> Simulates mips architectue pipeline according to the configurations.
• simulator.hpp:
  1. SaturatingBranchPredictor=> Makes predictions based on the history of that particular branch.
  2. BHRBranchPredictor=> Makes predictions based on the history of the entire file.
  3. SaturatingBHRBranchPredictor=> Predicts which of the above two strategies should be used for making predictions and then uses it for prediction.

Other files:

• main.cpp, 5stage.cpp, 5stage_bypass.cpp, 79stage.cpp, 79stage_bypass.cpp : Are copies of the same file. Create an instance of Simulator.
• Makefile: To define the make commands.
• Readme.md: The readme file for the code.

Design Decesions:

• For first in first out, the stalls are inserted only before WB stage.
• There can be two WB stages in the same cycle for a 7-9 pipeline if one of them is non operational.
• For 7-9 stage pipeline, the stages in which the stalls occur are sometimes interchanged for simplicity of the design. This does not affect the overall pipeline.
• In 7-9 stage pipeline without byassing, regsiters can only be read at RR stage.
• In 5 stage pipeline, the registers in Regsiter File can be read anywhere.
• There are no latches or cycles in the code and the stages are just represented as a block of delay and have no functionality of their own. The functionality of the code is executed separately from the pipeline.