You could, for example, insist that stack pointer changes occur with interrupts disabled. The problem is the 8086 has a nonmaskable interrupt that uses the stack, and software can’t stop it.

You’d think that the 8086 microprocessor, a 40-year-old chip with a mere 29,000 transistors on board that kicked off the 16-bit PC revolution, would have no more tales left to tell. But as [Ken ...