r3000 cache flush q

[David Holland <dholland-mips%netbsd.org@localhost>]

r3k_pdcache_do_inv in cache_r3k_subr.S contains the following per
cache line:

        sb      zero, 0(a0)
        sb      zero, 4(a0)
        sb      zero, 8(a0)
        sb      zero, 12(a0)
        sb      zero, 16(a0)
        sb      zero, 20(a0)
        sb      zero, 24(a0)
        addu    a0, 32

that is, it touches each word except the last one.

Can anyone explain this? One would think it would either need exactly
one word in the cache line to be patted, or all of them, but not all
but one. (The doc I have suggests that only one is necssary.)

It's been this way ~forever so maybe nobody knows, but I thought I'd
ask...

-- 
David A. Holland
dholland%netbsd.org@localhost