How does the CPU know how to find the program to service the mouse?

The CPU finds the program to service the mouse through an interrupt-driven mechanism. When the mouse is used, it generates an interrupt signal that is sent to the CPU. The CPU then references an interrupt vector table, which contains addresses of the corresponding interrupt service routines (ISRs) for various devices, including the mouse. Once identified, the CPU executes the appropriate ISR to handle the mouse input.