CLogic, CO120.3 C Project Extension

This is as part of Imperial College London’s CO120.3C Programming (C) Extension course, a project extension collaboratively implemented by Chloe Lau, Karan Obhrai, Leo Unoki and Oliver Federico, for Group 13, Academic Year 2019/20, First Year Computing.

Introduction

As part of our CO112 Introduction to Computer Systems course, we have built strong logic and circuit knowledge with a variety of software. In order to enhance the learning experience , we have decided to build an extension to our C Project by building a logic gate/combinatorial circuit design emulator, CLogic, with easy instructions for students to use within , and beyond the course.

The CLogic program would take in instructions to build a logic gate circuit through a parser , then the function would find the value of each output by a recursive trees approach. The program would allow easier control of multiple (n >= 2) inputs being processed to one operation, with an efficient handling method and possibly faster for theoretical circuits designs.

CLogic Input Rules

Each line of text can take two forms (–> excluded):

• <NAME> INPUT

• <NAME> OUTPUT? <FUNCTION> <INPUTS...>

? wildcard indicates optional.

Gates Rules:

• OR (Minimum 2 inputs)

• AND (Minimum 2 inputs)

• NOT (1 Input)

• XOR (Minimum 2 inputs)

• XAND (Minimum 2 inputs)

• NOR (Minimum 2 inputs)

• NAND (Minimum 2 inputs)

Approach

We have taken a trie approach instead of a graph approach

• Loops will throw an error! Something cannot directly or indirectly take it’s own output as it’s own input.
• This will be done because a gate can only take inputs previously referenced in the code (including it’s unable to take itself).

CLogic Input Rules

To run the test suite, run the ‘./extension_tests/testsuite_runner.sh’ shell script from a UNIX based OS machine. The last line will say “All tests passed” if the test suite passed all tests.

Example

Input

A INPUT
B INPUT
C OUTPUT OR A B

Output

<-START->
Input Gate: A Value: 0
Input Gate: B Value: 0
Output Gate: C Value: 0
<- END ->

<-START->
Input Gate: A Value: 1
Input Gate: B Value: 0
Output Gate: C Value: 1
<- END ->

<-START->
Input Gate: A Value: 0
Input Gate: B Value: 1
Output Gate: C Value: 1
<- END ->

<-START->
Input Gate: A Value: 1
Input Gate: B Value: 1
Output Gate: C Value: 1
<- END ->

Testing

Testing would run two tests from the subdirectory extension_tests, just run the file testsuite_runner.sh and it will run all the tests on terminal with the shell command, first to run the execute tests, then the comparison of a recursive usage with a manually coded expected output.