Yay! for mvme5500

[Peter Dufault]

I did "hello world", finally, on the MVME5500 on 4.7

A few "heads up", though.  Take these with a grain of salt since I'm 
just starting out, but I think they're real problems.

1. The linkcmds in the BSP in 4.7 (and supplied for 4.6) don't seem to 
correspond to the linkcmds used to build the "mvme5500-cexp.bin" that 
came with the MVME5500 patches for 4.6.  That binary obviously starts 
at 4000000, but the linkcmds put the start at 4000100.  Maybe the folks 
at Brookhaven only use incremental linking using cexp as a boot loader 
and haven't noticed?  Don't get me started on "incremental linking 
considered dangerous", you should see some of the vxWorks startup 
scripts I've seen.

2. bspstart.c is calling "initialize_exceptions()" before setting up 
Cpu_table.  For me (and I hope this is how it should be) this results 
in a call to mpc6xx/exceptions/raw_exception.c, and that checks 
Cpu_table.exceptions_in_RAM as a boolean to decide what to do.  Since I 
kept carefully zeroing out memory for repeatability before starting 
things up, that was testing false, and nothing was working. When I saw 
what was going on I initialized Cpu_table.exceptions_in_RAM to 1 before 
calling initialize_exceptions(), and then things started working. (I 
assume that test is done before BSS is defined to be cleared out).

A quick check of other powerpc bspstart.c's shows that they also call 
initialize_exceptions before setting up Cpu_table, they should maybe be 
checked for similar problems.

3. I get all my "Hello World" output, but the Motorola "MOTBoot" 
dramatically complains when it finishes up.  I assume this is just my 
getting started.

Peter

Peter Dufault
HD Associates, Inc.