Hi, I'd like to have any opinion/thought about TBIS() operation.
TBIS() is to make sure to eliminate a TLB entry which has the target
vaddr.  This is the subject of ASID matching, and it effectively means
TBIS() can invalidate the entry belongs to "current" ASID given any
curcumstances of system state.  Now, should TBIS() op eliminate
every TLB entry refers one particular vaddr?  This might be overkill
degrading TLB performace, however, TBIS() op is likely, I guess,
in use to dissolve COW condition.   I learnt MPC860/850 TBIS()
like insn works in this way.  MIPS would require entire TLB
traversing and might be too costy to implement.  Thought?

Toru Nishimura