ISA(X86 Arm or RISC-V) describes program's abilities of an abstract computer by defining state transition rules.
We use state machine model to help us better understand the complex computer system. It's effective.
The design of a CPU Chip can be accounted as a precess of unifying program, abstract computer and physics CPU's state machine behaviour.
| Program | Abstract Machine | CPU | |
|---|---|---|---|
| State | {<V, PC>} |
{<R, M>} |
{Timing Logic Circuit} |
| State Transition Rule | Semantics of C statements | Semantics of instructions | Microprogrammed logic circuit |
| FM | C Standard Manual | Instruction Manual | Architecture Design Document |