Instruction Set Architecture (ISA) is defined by a deterministic mapping between hardware primitive operations and software-level computation primitives, where machine instructions serve as the exclusive interface for processor execution. The core theoretical mechanism involves encoding specific operations into fixed-width binary words utilizing distinct formats—R-type, I-type, J-type—to specify opcode identifiers, operand registers, immediate constants, or branch offsets within a limited register file architecture. This abstraction layer enables hardware designers to optimize performance and cost by defining strict bounds on data size (e.g., 32-bit), addressing modes, and instruction length, thereby establishing the formal contract upon which high-level languages are compiled via intermediate machine representations such as assembly language.
Instruction Set Architecture (ISA) is defined by a deterministic mapping between hardware primitive operations and software-level computation primitives, where machine instructions serve as the exclu…