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  • Interruption can be triggered by CPU. For example, a key is pressed on keyboard.
  • CPU and RAM do not need drivers.

Program Counter (PC)

Program counter (PC) is a componenet of CPU. It points to an address (in main memory) that contains the next instruction to be executed.

Register File

The register file is a set of registers (storage devices) of word length.

Arithmetic/Logic Unit (ALU)

Arithmetic/logic unit (ALU) is a componenet of CPU. The ALU do operations on the specified registers.

Bus Interface

Bus interface is a componenet of CPU. It accepts the information from the buses. For example, a key is pressed.

Examples of CPU instructions

  • Load: Copy from main memory to register.
  • Store: Copy from register to main memory.
  • Operate: Copy the content of 2 registers to ALU and performan an operation and write the result to one of the registers.
  • Jump: Extract a word from a instruction and put into PC.