The circuits used in the CPU during the cycle are:
-
Program counter (PC) - an incrementing counter that keeps track of the memory address of the instruction that is to be executed next.
-
Memory address register (MAR) - holds the address of a memory block to be read from or written to.
-
Memory data register (MDR) - a two-way register that holds data fetched from memory (and ready for the CPU to process) or data waiting to be stored in memory
-
Instruction register (IR) - a temporary holding ground for the instruction that has just been fetched from memory
-
Control unit (CU) - decodes the program instruction in the IR, selecting machine resources such as a data source register and a particular arithmetic operation, and coordinates activation of those resources
-
Arithmetic logic unit (ALU) - performs mathematical and logical operations
阅读(803) | 评论(0) | 转发(0) |
