Arithmetic and Logic Unit (ALU)

And now for something different. We have used an ALU in all the simulators. Here, you will learn about the ALU in greater detail and about its testing.

The following Python code demonstrates the implementation of an 8-bit, 16-function ALU. We have added several contemporary operations that some computers provide, such as modulus, minimum, and maximum. The alu function is called with the op, a, b, cIn, and display parameters. The op parameter is in the range 0 to 15 and defines the function. The a and b parameters are two 8-bit integers in the range 0 to 255, cin is a carry in, and display is a flag. When display is 0, no data is printed. When display is 1, the inputs and results are printed by the function. This feature is for debugging.

This code demonstrates the use of Python’s if...elif construct to decode the arithmetic operation. We have also included a dictionary structure that enables us to print out the operation code by name. In...