Correct, divide by zero is one of the original five defined IEEE754-1985 exception. But the default behavior then and now is to produce that defined result ment

Correct, divide by zero is one of the original five defined IEEE754-1985 exception. But the default behavior then and now is to produce that defined result mentioned and continue execution with a flag set ("default non-stop"). Further conforming implementations also allow "raiseNoFlag". It's well-defined is all that really matters AFAIC.