Subject: Re: A Boot!
To: Ben Harris <bjh21@cam.ac.uk>
From: None <Chris.Smith@raytheon.co.uk>
List: port-arm26
Date: 05/02/2000 11:35:46
** > Does BBBB's page memory map output have a key?
**
** Erm, RTFS?  ALternatively, I suppose I could do so...

Could have done - unfortunately, I didn't have much time or a handy
Arc TRM etc...  My knowledge of the low level system is crappy without
the TRM.

** Each character in the map represents one page of (physical) RAM.  The
** ticks along the top are to stop you getting lost.  The characters in the
** map indicate what the memory's being used for (actually where it's
** logically mapped):
**
** 0 -> zero-page
** + -> BBBB workspace
** * -> Free space (BBBB wants to put the kernel here)
** d -> RAM disc
** s -> System sprite area
** m -> RMA
** h -> System heap/stack
** f -> Font cache
** S -> Screen memory
**
** [ This section is from memory ]
**
** On a machine with 32k pages (which is all NetBSD/arm26 supports), the
left
** half of the first line is potential screen memory, and hence not used by
** BBBB.  The next page is usually zero page under RISC OS, and is used for
** zero page under NetBSD.  The next is usually system heap under RISC OS,
** and is used for process 0's kernel stack under NetBSD.  The next is used
** for the message buffer under NetBSD.  Pages from there on are used to
load
** the kernel, and must be free if BBBB is to do so successfully.  Future
** bootloaders should load the kernel into whatever pages are free, then
kick
** out RISC OS and shuffle them into the right shape.  This is left as an
** exercise for the enthusiatic reader.

Brilliant - that answers all my Q's.  Note:  I am enthusiastic - but not
that much :)  BBBB works ok, so I think I'll live with the supervisor
restarts.

** > There is only one problem (mine), is that my monitor loses sync
** > after about 2 seconds of it booting (sync too low).  I have a
** > proper Acorn monitor AKF60 in the post so I'l have a proper boot
** > soon :)  I'll even see things past the copyright message before
** > it loses sync then :)
**
** What monitortype is the machine configured for?  VGA or SVGA (sorry,
can't
** remember the numbers) should drive most PC monitors happily.

I've tried configuring all monitor types - It's a new monitor (sony 19"
FD Trinitron thing).  It's hsync is a bit suspicious (low point is 31khz
rather than 30khz.  On the other hand, My Hansol and my CTX dont sync
either.  Any ideas?  I think the vidc on that Arc might be either buggy
or broken.  That's what happens when you grab old school fileservers...
We'll see how the AKF60 goes I think (scheduled arrival Thursday).
Depends if I can stop playing Zarch or not though :)

** > [for Ben >> Can we have a serial console for development? :) ]
**
** Well, I can probably do it for Archimedes-class machines (which use
** 6551s), but I haven't got an IOEB machine (which use 16450-clones), so
** testing it there is a little harder.

Okay - understood.  I had a feeling that the A5k was going to be a pig
on this.  They magically decided to drop the proprietry arc hardware in
favour of more PC-like stuff.  How hard do you think it'd be to import
a serial driver from somewhere else and attach it (the hard bit)?

Any views on cross-compiling yet?

Chris.