Question

1. What is RTL? Provide a basic example of an operation in the notation and explain it and What cycle is repeatedly executed by the CPU? Give the name and provide an explanation

Answer 1

RTL is a simple, human-oriented language that specifies the operation, registration, and communication of steps to take place within the CPU to carry out higher-level instructions. It is a type of intermediate representation (IR) that is very close to the assembly language, such as used in a compiler.

RTL Operations:

Operation Category	Syntactic Notation
Transfer of data between registers multiple target registers are loaded in parallel	RegA RegB [,RegC]... Reg field RegB [,RegC]...
Load a register with certain, common constants (e.g., 0, 1, 2, 4). Only certain registers may have this operation. Typically X and Y. All registers may have a 0Rn operation, however.	4 X
Memory operations. Implicitly use MAR and MDR	Read Write Wait
ALU operations. These operations only apply to X and Y registers and place the result in Z	Add Sub etc.

The main job of the CPU is to execute programs using fetal-decode-execute cycles. It is also known as the instruction cycle.

1. The processor checks the program counter to see which instruction is next.
2. The program counter gives an address value in the memory of where the next instruction is.
3. The processor fetches the instruction value from this memory location.
4. Once the instruction is fetched, it must be decoded and executed. For example, this could involve taking one value, putting it into the ALU, then taking a different value from a register and adding the two together.
5. Once this is completed, the processor goes back to the program counter to find the next instruction.
6. This cycle is repeated until the program ends.