Implementation of 16-Bit Hack CPU on FPGA

The design and implementation of a 16-Bit hack CPU, a modular processor, is presented in this paper. The paper is intended to showcase the process involved in building a complex circuit capable of performing real-world computations, from the most basic component used for digital data representation that is the CMOS. The design methodology used is a bottom-up approach, this starts with the construction of basic gates and moving up to major components like the program counter, ALU, etc. and ends with the complete construction of the CPU using the previously built components in a modular manner. This paper aims to give the reader a complete understanding of the functioning of a simple computer in a digital electronics abstract. This paper will also give an idea about the data flow in a CPU triggered by a CPU. An idea regarding the way a low-level programming language controls this data flow can also be understood. This CPU design is easily implementable on an FPGA and is hence a great tool to teach students about the basics of Computer Architecture and Digital System Design. The CPU reads instructions from the ROM and performs operations using the A register, D register, or the RAM units based on the instruction type. There are mainly two types of instructions, instructions and C instructions. The A instructions have the sole purpose of storing values into the A register while the C instruction can perform multiple operations.