Anyone using an IBM RISCWatch ICE?

[Wright, David]

Hi,

I've been attempting to use an IBM RISCWatch ICE on a Walnut system
and I'm having problems.  (Spare me any lectures about how I should
be using a BDI.  I'm just trying to find out how usable the IBM is,
since it's already here.)

The specific problem I'm trying to solve is this:  how do I set a
breakpoint early in kernel startup, say at start_kernel (just as
the MMU is enabled)?  I've tried booting the Walnut so that it
comes up into its ROM monitor, then stopping it with the ICE, and
setting a hardware breakpoint at the start_kernel virtual address.
Problem is, when I start the CPU running again, the Walnut is no
longer responding to the keyboard (serial line).  Can't do anything
except reset it at that point.  Using the ICE reveals that the CPU
is still running, but I have no real idea what it's doing.  It sure
isn't responding to the serial port.

As an alternative, I tried setting a hardware breakpoint at the
physical address of "start_here".  That doesn't hang, but the
breakpoint is never hit, either.

Any ideas gratefully accepted.  I've tried this kind of thing with
a BDI and had no problems.

  -- David Wright, InfiniSwitch Corp.


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