68000 and TCP memory usage

[Chris Johns]

Antti P Miettinen wrote:
> 
> 2. How to correctly handle having vectors in read-only memory? I
>    managed to get the hello world running by making the real vectors
>    point to jump instructions jumping through a fake vector table and
>    by making _VBR point to this fake table but the ticker test crashed
>    somewhere with this setup. When I made the real vectors R/W, ticker
>    test started working.
> 

For a 68302 I switch the RAM and ROM so I have RAM at 0 giving you a RAM
vector table. The 68302 does not have a VBR and so the vector table is
set to reside at 0. I make a ROM vector table which I copy to RAM just
before doing the switch. The ods68302 BSP has code to do the switch.

Once in RAM, the standard RTEMS score code should work.

-- 
 Chris Johns, mailto:cjohns at cybertec.com.au mailto:ccj at acm.org