some newbie questions

sebastian ssmoller sebastian.ssmoller at
Thu Feb 19 19:10:18 UTC 2004

finally i used the approach: incrementing a variable an see where it

> 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 :(



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