jsm explained to me that the F?CE and P?TLBE instructions should only be used "for flushing the entire data or combined cache". The operands of F?CE/P?TLBE are "an implementation-dependent function of the effective address", essentially an opaque data type that varies per processor. The operand of F?C/P?TLB is a virtual address, so is the right thing to use for flushing a range of addresses. -P