[OpenBIOS] [PATCH] Use exception vectors from ROM instead of copying them to page zero

[Mark Cave-Ayland]

On 26/05/14 17:48, Segher Boessenkool wrote:

>>> Instead of copying the exception vectors from ROM to page zero use the
>>> Interrupt Prefix bit of the CPU to use the vectors at the ROM address.
>>> This simplifies the startup routine a little bit and avoids using
>>> addresses that can be overwritten by clients. In particular MorphOS
>>> writes to address 0x80 during boot which corrupted the exception
>>> return code causing a crash.
>
> Many OSes use 0000..00ff for their own purposes.  OpenBIOS should
> not use that area for anything, for its own good.

Really? That's really useful to know - is this documented anywhere so we 
can find more information about it? While the patch works, like Alex I'm 
slightly nervous as to why it was written this way in the first place. 
Are there any other assumptions that we're not aware of?


ATB,

Mark.