fetch-execute cycle

1 definition found

fetch-execute cycle - Free On-line Dictionary of Computing (26 May 2007) :

  fetch-execute cycle
  
     <architecture, processor> The sequence of actions that a
     central processing unit performs to execute each machine code
      instruction in a program.
  
     At the beginning of each cycle the CPU presents the value of
     the program counter on the address bus.  The CPU then
     fetches the instruction from main memory (possibly via a
     cache and/or a pipeline) via the data bus into the
     instruction register.
  
     From the instruction register, the data forming the
     instruction is decoded and passed to the control unit which
     sends a sequence of control signals to the relevant function units
      of the CPU to perform the actions required by the
     instruction such as reading values from registers, passing
     them to the ALU to add them together and writing the result
     back to a register.
  
     The program counter is then incremented to address the next
     instruction and the cycle is repeated.
  
     The fetch-execute cycle was first proposed by John von Neumann
     .
  
     (1998-06-25)