This is more of a computer engineering question. But can someone help me figure out how to design an 8 bit ISA for a calculator. Thanks in advance

objective: The objective of this laboratory is to design an 8-bit calculator ISA, implement a simulator, and test your ISA and simulator. Equipment and software: The lab will use the C programming language. All lab computers are installed with C compiler. You can also use other programming languages for implementing the simulator. Specification of the calculator: The calculator ISA must support the following operations. You may encode other functions in the ISA as you wish. Address four 8-bit registers. All registers should have value "0" before their first write. oad a 4-bit immediate number into a register. The immediate number should be sign- extended. Add subtract between two registers and store the result in a third register. Display a register's content to console Compare two registers. If they are not equal, execute the next instruction. If equal, the instruction should support the choice of skipping either the next 1 or the next 2 instructions