Re: pmap without RAM in the first 256MB segment

[Matt Thomas <matt%3am-software.com@localhost>]

On Mar 16, 2010, at 7:16 AM, Frank Wille wrote:

> Hi,
> 
> a few days ago Jukka Andberg made the first successful tests for port
> amigappc on an A1200 with a BlizzardPPC board. He noticed a problem
> which is hard for me to fix:
> 
> The pmap_bootstrap() can only work when it finds RAM between 0x00000000
> and 0x10000000 (is this correct?). For the CyberstormPPC I was lucky that
> the RAM base address of 0x08000000 is in this area. But what can we do for 
> computers without (useful) RAM in the first segment (probably only Amigas
> are affected)?
> 
> Is it easy to fix/enhance pmap, or should I regard that a show-stopper?

Since exceptions are delivered to address 0x0000-0x2fff, I not sure how it can 
even work unless they use the boot vectors at 0xfff00000 (MSR[IP] = 1).  If 
that's true, then it's going to require significant work to get OEA working.