CPU register

The register is CPU Component part , Registers can be used for temporary storage Instructions 、 Data and address （ These are the keys to program execution ）.

stay CPU At least there must be 6 A register

• Instruction register （IR）
• Program counter （PC）
• Address register （AR）
• Data register （AC）
• Accumulation register （AC）
• Program status word register （PSW）

Instructions ： opcode + Address code

Data register

Data Register, Mainly used by main memory （ Memory ） An instruction or a data word read .（ One word =16bit）

Address register

Address Register, To preserve CPU The address of the main memory unit currently accessed .

Because in main memory and CPU There is a difference in operating speed between , Therefore, the address register must be used to temporarily save the address information of main memory , Until the access operation of main memory is completed .

Program counter

Program Counter, Used to indicate the address of the next instruction in main memory , Before the program is executed , First, the first address of the program must be , That is, the main memory unit where the first instruction of the program is sent into PC, therefore PC The content of is the address of the first instruction extracted from main memory

Accumulation register

Accumulator,⼀ A pass ⽤ register . When the arithmetic logic unit of the arithmetic unit ALU Of board ⾏ Arithmetic or logical operation , by ALU Provide ⼀ individual ⼯ Working area , It can be for ALU For the time being ⼀ Operands or operation results
Instruction register
Instruction Register,⽤ To save the current execution ⾏ Of ⼀ Orders , Hold fast to ⾏⼀ Instruction time ,⾸ First read the instruction from main memory into the data register , And then transmit ⾄ Instruction register
Program status word register
Program Status Word, To represent the current operation state and program ⼯ do ⽅ type , The program status word register is ⼀ A register that stores various status condition flags