Microprocessor Simulation

A microprocessor performs different operations on its inputs, based on a signal that tells it which operation to perform.

In this exercise, you'll write code to simulate what a processor does.

A program, from the view of a microprocessor, is a set of operations and values. The processor will perform each operation on the values, one by one. For our simplified example, it might look like:

add 8 16
mul 10 3
or 1 0
nand 1 1

At each step, our model of a processor outputs a value. For this pretend program, the output at each step would be:

24
30
1
0

Processor Operations

Below are the processor operations that you should support, and what they should do.

Operation	Description	Sample	Output
noop	Do nothing, print empty line	noop
add	Add arguments	add 3 140	143
mul	Multiply arguments	mul 10 21	210
gt	Check if first is greater than second	gt 3 10	0
or	Logical or	or 6 0	1
nand	Logical nand ("not and")	nand 1 1	0
min	Find the minimum value of arguments	min 14 8 103	8
shift	Shift left by a number of bits	shift 8 2	32
invalid	Any non-valid operations	not an op	invalid operation not an op

Notes:

• All of the operations are defined for integer arguments. Floats or other arguments are invalid.
• Most operations take exactly two arguments.
• noop takes no arguments (it should be invalid if there are any arguments). min should work with 2 or more arguments.
• The logical or and nand operations always print out a 0 or 1, no matter their inputs. 0 is treated as false, any other number is treated as true.
• shift takes the bit representation of its argument, and moves the bits left, with the number of places to shift given by the second argument. So, 8 (00001000) gets shifted left by 2 to become 32 (00100000).
• shift is only defined for positive arguments. It is invalid for negative numbers or zero.
• For our processor, numbers have arbitrarily many bits. Don't worry about overflow or truncation for add, mul, or shift.
• If the processor encounters an invalid operation, it should print an error message and stop.

Starter Code

main.py has the function run already written for you. It reads a file containing a program and calls the process function on each line.

There is also a __name__ == "__main__" module guard, to call the run function if the file is executed on the command line.

Your task is to implement the process function (right now it just prints each line) and any helper functions you need.

Testing

As you develop your program, try running your helper functions with sample inputs, to check that they are returning the results you expect. To run the first whole sample program, enter python main.py sample1.txt in the terminal. You can use the same pattern for the other samples, or write your own sample.

The automated tests will call the process or run function with some sample operations or programs, and check that the functions print the correct result. How you organize your code is up to you -- your helper functions are not tested directly in the automated tests.

Hints

First, you'll need to turn the line of input into an operation and its arguments. All of the values in the programs will be ints, so you should convert the values from strings.

In order to write this program effectively, you should split the problem into lots of small functions, and then use a single function to decides which other function to call.

Note: Python has built-in functions called or and min, so you can't use those as names of functions in your code. Rename the functions to something else.