checked exclhi rings:
{ a, b, c }
checked excllo rings:
	0	a : 1
	0	b : 0
	0	c : 0
warning... 
ERROR: exclhi violation detected!
ring-state:
	a : 1
	b : 0
	c : 0
but node `b' tried to become 1.
The simulator's excl-check-lock state is no longer coherent; do not bother trying to continue the simulation, but you may further inspect the state.
You probably want to disable excl-checking with `nocheckexcl' if you wish to continue the simulation.
WARNING: detected exclusion violation, but because the simulation is
continuing (current policy), further exclusion checking is automatically
disabled because the checking structures would be incoherent otherwise.
	0	b : 1
	0	b : 0
