Torubles with remote stub for m68k

Daniel Jacobowitz
Mon Jun 24 14:13:00 GMT 2002

On Mon, Jun 24, 2002 at 05:04:51PM -0400, Peter Barada wrote:
> I'm in the midst of bringing up a remote stub for coldfire using
> gdb-5.1.1, and I'm having troubles getting it to step.  My stub does
> not suppor the 'Z0' or 'e' packets so gdb has to fall back to the
> insertion of a 0x4e41 (trap #1) instruction into the stream as a breakpoint.
> when it hits the breakpoint, a 'si' command is expected to:
> 1) Restore the memory overwritten by the 0x4e41 (trap #1) instruction
> 2) Step the processor by setting the T bit in the SR register and
>    return from gdb
> 3) Reinsert the previously removed breakpoint.
> (and seen in version 4.16)
> When I execute that with gdb-5.1.1, it attempts to step the processor
> without removing the trap instruction so the target processor never
> steps past the trap instruction.
> Here's a cut back version of the remote protocol exchange(via set
> debug remote 1) to show what's happening:

You might want to try disabling binary download in your stub just to
make sure... normally, the client will remove breakpoints itself.  This
definitely still works in 5.2.

You also should try with 5.2 or CVS rather than 5.1.1, probably...

Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer

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