Instructionset
An instruction set, more formally known as an instruction set architecture (ISA), is the formal collection of instructions that a processor can execute, together with the data types, registers, addressing modes, and encoding schemes used to implement those instructions. The ISA defines the software-visible interface to the processor, including how instructions are fetched, decoded, and executed, as well as the semantics and potential side effects of each instruction. It also encompasses privileged instructions used by an operating system and the rules for interacting with memory, I/O, and other system resources.
An instruction typically consists of an opcode that specifies the operation and a set of operands that
ISAs are often categorized by design philosophy, such as CISC (complex instruction set computing) and RISC (reduced