A buffer underflow that overwrote a pointer that overwrote 1 byte of code in the multiplication library (no hardware multiplication or memory protection, by the

A buffer underflow that overwrote a pointer that overwrote 1 byte of code in the multiplication library (no hardware multiplication or memory protection, by the way) that caused unsigned multiplication to be handled as signed multiplication (or perhaps vice versa). This didn't manifest until much later, of course.