CIR
OUTPUT
Instruction
ACCumulator(ACC)
this register is used when carrying out ALU calculations;it stores data temporarily during the calculations
ACC
CU
Process
Decode
Address
Memory Address Register（MAR）
this register stores the address of the memory location currently being read from or written to
Data Bus
Fetch
Current Instruction Register(CIR)
this decoded register stores the current instruction going to be decoded and executed
Fetch–Decode–Execute Cycle
Control Bus
MAR ← [PC] PC ← [PC] + 1 MDR ← [[MAR]] CIR ← [MDR]
Memory (RAM)
MAR
Address Bus
Address(WB)
Memory Data/Buffer Register (MDR / MBR)
this register stores data which has just been read from memory or data which is about to be written to memory
CPU
Data/Instruction
ALU
Data(WB)
PC
MDR
Program Counter(PC)
this register stores the address where the next instruction to be read can be found
