"Hamish Guthrie \(Mail Lists\)" <[EMAIL PROTECTED]> writes:
> I did a lot of experimentation with DoC Millennium because we have a tricky
> (large) SDRAM sizing algorithm which does not entirely fit into the 512
> bytes available. I was also in contact with the guys at M-Systems and the
> bottom line is that it is not possible to page the DoC. It is not possible
> to page data into the SDRAM on the Millennium. Our thoughts were to have a
> uniform exit/entry from to contiguous pages of the device and to do some
> form of paging, but it is just not possible.
On a few processors you can play games with executing code out of the
icache from a region that isn't backed by memory. I have only been
able to get this to work with a P6 however :( And since you are
running an older processor it probably isn't even possible to
write-back cache everything.
> The only option with larger code is to use the Millenium+ or the new
> DOC2000, but of course these devices are only available in a 48-pin TSOP-I
> package so it is a problem using them as an aftermarket device, unless of
> course someone made an adapter to fit the new devices onto a 32-pin DIP
> socket.
>
> Just for your info, the 2 new devices are:
>
> MD2811-D32-V3 - 32MByte Doc Millennium Plus with 1k SDRAM (8 or 16-bit data
> bus)
>
> MD2211-D16-V3 - 16MByte DoC2000 with 1k SDRAM (8 bit data bus)
>
> In our environment though, we generally have an embedded system with the
> SDRAM soldered directly on the board so we *SHOULD* know what we are dealing
> with! At this point in time we are just hard coding the SDRAM type into the
> LinuxBIOS.
Interesting. For the SiS735 it looks like we need to write so it uses
a normal ROM chip then. With etherboot and a few other pieces as an
option this is much less of a problem then it once was.
Eric
