CPU

• 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.