Instruction cycle: refers to the ti

Instruction cycle: refers to the time from the fetching of the computer to the completion of the execution of the instruction. The process of the computer executing instructions can be divided into the following three steps: 1. Fetch (fetch instruction ), that is, find the corresponding instruction address from the PC register, and load the specific instruction from the memory into the instruction register according to the instruction address, Then increment the PC register to execute the next instruction in the future. 2. Decode (decoding), that is, according to the instructions in the instruction register, parse into what kind of operation to be performed, which kind of instruction is R, I, J, which register, data or memory address to be operated specifically. 3. Execute (execute instructions), that is, actually run the corresponding R, I, J specific instructions, perform arithmetic logic operations, data transmission or direct address jump. In the stage of fetching instructions, our instructions are placed in memory (that is, memory). In fact, the process of fetching instructions through the PC register and the instruction register is operated by the controller (Control Unit). The instruction decoding process is also performed by the controller. Once it reaches the stage of executing instructions, whether it is an R-type instruction for arithmetic operations and logical operations, or an I-type instruction for data transmission and conditional branching, it is operated by the arithmetic logic unit (ALU), that is, processed by the arithmetic unit . However, if it is a simple unconditional address jump, then we can do it directly in the controller without using the calculator instruction life cycle.