Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

INSIDE THE COMPUTERInside CPUs(cont’)

‰ALU (arithmetic/logic unit)

¾Performs arithmetic functions such as add, subtract, multiply, and divide, and logic functions such as AND, OR, and NOT

‰Program counter

¾Points to the address of the next instruction to be executed

ƒAs each instruction is executed, the program counter is incremented to point to the address of the next instruction to be executed

‰Instruction decoder

¾Interprets the instruction fetched into the CPU

ƒA CPU capable of understanding more instructions requires more transistors to design