some newbie questions

Ed Sutter els at
Thu Feb 19 19:35:53 UTC 2004

I just scanned futher through the manual and it appears that the first
instance of the MBAR address has a typo.  All other references in the
manual use 0x3ff04, not 0x33ff04.
Sorry about that!

sebastian ssmoller wrote:
> hi,
> finally i used the approach: incrementing a variable an see where it
> stops.
> > Seb,
> > Just reset the board (don't powercycle).  In most cases this doesn't
> > corrupt memory.  Usually, assuming you have a reset or NMI type
> > of button, you can get yourself back to the monitor, then in RAM
> > space you essentially have the equivalent of a core dump.
> i did so and it worked perfectly well.
> i started debugging at c/src/lib/libbsp/m68k/gen68360/start/start.S
> where the start symbol which i call is defined. i found out that the
> board hangs immediately at step 4 where mbar is set.
>   /*
>    * Step 4: Write the MBAR
>    */
>     movec   dfc,d1          | Save destination register
>     moveq   #7,d0           | CPU-space funcction code
>     movec   d0,dfc          | Set destination function code register
>     movel   #m360+0x101,d0  | MBAR value (mask CPU space accesses)
> /* with the execution of the next line the board will hang */
>     movesl  d0,0x3FF04     | Set MBAR
>     movec   d1,dfc          | Restore destination register
> the original addr of the MBAR was 0x3ff00 as described in the 68360
> manual (which failed). i read again the doc of my board and it says that
> MBAR is at 0x3ff04. so i changed the value but nothing happens - the
> board still hangs :(
> thx
> regards,
> seb
> (...)--
> Microsoft: Where do you want to go today?
> Linux: Where do you want to go tomorrow?
> FreeBSD: Are you guys coming or what?
> OpenBSD: Hey guys you left some holes out there!

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