John, i have no clue about the hardware-
one thing: the XC can only be used to clear it- the MVHI could be used to create any memory-configuration possible into the half-word- so... The stmt ".... product's documentation said it was supported on a z9" is correct if it continues with ... "---when compiled with the right archlvl" just saying Martin Trübner; everything around "PoOps of z/arch"
