Re: Porting to NuBus PowerMacs

[Tom Vier <nester@erols.com>]

On Tue, 12 Jan 1999, David A. Gatwood wrote:

> It's a lot harder than this, unfortunately.  The NuBus machines' memory
> isn't contiguous.  Thus, code would have to be written and/or obtained to

doh!

> find out what memory is available in the machine and where that memory is
> located in RAM.  That's going to be a nasty problem unless some code is
> pulled from the MkLinux booter.  I'd expect that to also require a
> substantial number of changes to the way memory is handled in linux, but I
> could be wrong.

hhmmm. don't some other arch's have non contiguous memory?

> Beyond that, it will also require changes to irq.c to handle the interrupt
> controller and a lot of code for DMA, if that's desired (I don't think
> it's even remotely similar, AFAICT).  Of course, that stuff can be
> obtained from Mach, but it'll be a lot of work.  Oh, and the i/o base
> address is different, which may or may not be a problem, and supporting
> certain pieces of hardware (which will remain nameless) will also require
> speed penalties (this is the other reason MkLinux is slower than
> LinuxPPC...).

what pieces of hardware? important ones?

--
Tom Vier - 0x82B007A8
thomassr@erols.com       | goto the Zero Page at:
Tortured Souls Software  | http://www.erols.com/thomassr/zero/


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