Mid-90s, a very large cell phone company at the time, working on a car phone (the head units had their own microcontrollers).... Discovered that the interrupt s

Mid-90s, a very large cell phone company at the time, working on a car phone (the head units had their own microcontrollers).... Discovered that the interrupt service routine was calling the reset vector instead of returning from the keypad interrupt. The original author apparently didn't understand how it was supposed to work, and a simple RTS would eventually overflow the stack....so on every keypad interrupt the whole code flow started over from reset. Worked surprisingly well.