csim is a simple digital circuit simulator I'm working on for a course project. It is written in pure Scala with no dependencies.

• Simulation of digital circuits consisting of basic gates (AND, OR, NAND, NOR, INV, BUF, XOR)
• Working deductive fault simulator that supports all of the gates above
• Fully operational PODEM implementation (with XOR/XNOR support!)

1. Scala 2.11.x
   • Scala 2.12.x is supported, but JS target will not compile (yet!)
2. sbt 0.13.x

To build csim, first navigate to the root of the project directory i.e. where build.sbt is located.

You have two options for building csim:

• To build a JAR for Scala, run sbt csimJVM/package.
• To build a "fat" JAR for Java (includes Scala stdlib), run sbt csimJVM/assembly.
• To build an optimized version targeting JavaScript, run sbt csimJS/fullOptJS.

Look under the directory [jvm|js]/target/scala-2.11 for the output JAR or JS file.

csim has a growing test suite written using ScalaTest. To run the tests, simply type sbt csimJVM/test. All tests should pass (green).

Note: only the JVM target has a test suite, but since the bulk of the logic is shared between the JVM and JS targets, this is not a huge issue.

Quick example of a simple simulation. Input vector file is s27.in, circuit description file is s27.ckt (both found in jvm/src/test/resources).

import me.assil.csim
import csim.circuit.Bit
import csim.CircuitHelper
import csim.CircuitSimulator

import java.io.File

object Main extends App {
  // Read input file for circuit s27
  val inputs: Vector[Vector[Bit]] = CircuitHelper.parseInputFile(new File("s27.in"))
  
  // Read in circuit file
  val simFile: List[List[String]] = CircuitHelper.readSimFile(new File("s27.ckt"))

  // Create a CircuitSimulator object
  val sim = new CircuitSimulator(simFile)

  // Run the simulator for each input vector
  val outputs: Vector[Vector[Bit]] = inputs.map(sim.run)
}

Example of using PODEM to generate a test vector for the fault 13 s-a-1 for circuit s27.

import me.assil.csim
import csim.circuit.Bit
import csim.fault.Fault
import csim.podem.PODEM

import java.io.File

object Main extends App {
  // Read the circuit input file
  val simFile: List[List[String]] = CircuitHelper.readSimFile(new File("s27.ckt"))

  // Create a PODEM object 
  val podem = new PODEM(lines)
  
  // Create a Fault object
  val fault = Fault(13, Bit.High)

  // Run PODEM and store test vector
  val v: Vector[Bit] = podem.run(fault)
}

To use Csim.js from JavaScript, use the examples below to get an idea of the API.

Example of running a simulation given a circuit and an array of input vectors:

// Sample circuit input file, split into lines
const circuit = ["AND 1 2 3", "INPUT 1 2", "OUTPUT 3"];

// Two input vectors
const inputs = [[1,0], [0,1]];

// Init the simulator, and run it
const c = new Csim(circuit);
const outputs = c.run(inputs);

// Log the result - Array[Array[Int]]
console.log(outputs); // => [[0], [0]]

You can also run the PODEM algorithm in JS:

// Sample circuit input file, split into lines
const circuit = ["AND 1 2 3", "INPUT 1 2", "OUTPUT 3"];

// Fault is net 2 s-a-1
const fault = [2, 1];

// Run PODEM
const c = new Csim(circuit);
const vector = c.podem(fault);

console.log(vector);

For more examples, refer to the tests located in jvm/src/test/scala. The tests only cover the JVM target, but they should be sufficient to understand how to use (and extend) the JS API.