Port-vax archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: KA48 / KA660 cache differences



2015-08-24 9:16 GMT+02:00 Felix Deichmann <m4j0rd0m0%gmail.com@localhost>:
> As suggested by the docs, our code also clears the tags' VALID flags
> before enabling the cache, but I do not understand the corresponding
> line:
>
>     while(cnt--) { *p++ = 0x80000000L; p++; }
>
> Why is only every second tag written?

Answering my own question, above code is obviously correct:
"Writes to cache tag addresses write to the cache tag indexed by bits
<09:03> of the address."
In other words: Every second longword (address) maps to an actual cache tag.


Home | Main Index | Thread Index | Old Index