NP

Undocumented in source but is binding to C++. You might be able to learn more by searching the web for its name.

Values

Value	Meaning
NP`0`	not pairable
PU`1`	pairable in U only, never executed in V
PV`2`	pairable in V only
UV`(PU \| PV)`	pairable in both U and V
PE`4`	register contention exception
PF`8`	flags contention exception
FX`0x10`	pairable with FXCH instruction