RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction flag

[Paolo Bonzini]

> Another story, the sad story of the intel chip (I think it was
> the 80188) where Intel made use of Int 5, which was documented
> as reserved. Unfortunately, Microsoft/IBM had used this for
> print screen or some such. Intel was absolutely right that
> their documentation was clear and it was wrong to have used
> these interrupts .. but the result was a warehouse of unused
> chips.

Not really.  Just, no one used the BOUND instruction.  All computers 
running DOS (Intel, AMD, even the old NEC V20/V30 chips) still connect 
INT 5 to Print Screen.

Paolo