systems architecture Flashcards
State what is in the CPU
Control Unit
ALU
Cache
Registers
What are the 4 registers?
Program Counter
MAR
MDR
Accumulator
What does the Control Unit do?
It is in control of the CPU
It decodes and executes intructions
What does the ALU do?
Does all calculations and logical operations
Why would cache be used?
It is faster than RAM
What data does the cache hold?
It stores frequently accessed data
What does the Program Counter do?
Holds the memory location of the next instruction
What does the MAR do?
Holds the location in memory of the instruction to be fetched
What does the MDR do?
Temporarily hold the instruction fetched from memory
What does the Accumulator do?
It stores the results of calculations carried out by the ALU
What happens at the Fetch stage of the cycle?
Instruction is fetched from memory
What happens at the Decode stage of the cycle?
The Control Unit decodes the instruction
What happens at the Executed stage of the cycle?
The instruction is executed
