Joel Brobecker wrote:
>> And I believe that consistent behavior / semantics should be:
>>
>>    If you tell me that you are stopped at instruction 1000,
>>    regardless of whether you were going forward or backward
>>    when you got there, then I will expect that if I tell you
>>    to execute forward, you will execute the instruction at
>>    1000.
> 
> This makes total sense to me. I think I would be very confused
> by the debugger if I started going back and forth with a debugger
> that didn't follow the semantics above.

Thanks.  By the way I've revised this patch slightly,
as shown below.  Use "== reverse" instead of "!= forward".

Makes it do the right thing in the "unknown" case.