The F-D-E Cycle Flashcards
What does F-D-E stand for?
Fetch-Decode-Execute
How many stages does the FDE cycle have?
Seven
FDE Cycle - What is stage 1?
The memory address is stored in the PC and is copied into the MAR
What is stage 2 of the FDE cycle?
The address in the PC is incremented by one, The PC now holds the address of the next instruction to be fetched
FDE Cycle What is stage 3?
The processor sends a signal along the address bus, to the memory address held in the MAR
FDE Cycle - What is stage 4?
The instruction or data
held in that memory address is sent along the data bus to the memory data register (MDR)
FDE cycle - What is stage 5?
The instruction or data held in the MDR is copied into the current instruction register (CIR).
FDE Cycle - What is stage 6?
instruction or data is decoded
FDE Cycle - What is stage 7?
Return to stage 1
What does Fetch do?
Fetches the data needed
What does decode do
The calculations and decodes the information
What does execute do
Executes the output of the decode section
