My machine has no ISA support and the IO is handled by south-bridge which operates at PCI bus speed.SparrowOS wrote:Your time-out delay is hoeky, but works for reasons you probably don't understand. IN/OUT instructions move at ISA bus speed which is roughly 1uS.
Furthermore, newer CPU like Sandy Bridge has the south-bridge directly connected to the CPU with quickpath, and I suppose it run at even faster speed.
Anyway, IN/OUT instruction has no defined speed for modern machine, there are hundred of things can affect the timing.
Stop telling the un-true.