Mail Archives: djgpp-workers/1999/05/25/05:26:11
On Tue, 25 May 1999, Eli Zaretskii wrote:
>
> On Mon, 24 May 1999 pavenis AT lanet DOT lv wrote:
>
> > It appears that I was wrong. The problem is with hardware assisted
> > breakpoints (hbreak).
>
> I didn't try hbreak yet. I will see whether I can reproduce this
> problem tonight.
????
I was not able to get this problems otherwise. Only with hardware
breakpoints (hbreak). Normal breakpoints (break, tbreak) works Ok for me.
I didn't change anything in CVS version of DJGPP (except buggy .txh file
which doesn't matter)
>
> > First expression is that translation from interrupt to exception
> > (src/libc/go32/exceptn.S) fails for SIGTRAP when running under
> > debugger.
>
> The only change in exceptn.S was that, if it finds SS to be the DS
> alias selector, it puts the normal DS into the stack frame popped on
> return from exception, in effect forcing the stack to use the normal
> DS/SS selector once C code is running again.
I don't think this change is significant. I thought about another problem:
there is 2 places where exception can be tranlated to signal
(debuger and debugee) and when we are allowing to hook exceptions
this is a real problem. We have at least partially solved it,
but as it appears now - not fully yet.
> I don't know whether this can affect the debug support, but it should
> be easy to take this change out, rebuild GDB and see if the problem
> goes away. I can send you the diffs (which you will need to apply
> with "patch --reverse"), if you want.
>
> > I tested earlier binaries I had:
> > 5th Jaunary binary of gdb-4.17 (at that time there were rather
> > active work with dbgcom.c by Pierre and me). That binary
> > seems to get hardware breakpoint as required.
>
> Did that 4.17 binary use the current libc.a? If not, perhaps you
> could rebuild that 4.17 binary with the current libraries and see if
> the problem is in GDB changes or in DJGPP changes.
>
It used 2.02 and I only replaced needed modules (such as dbgcom.c).
Perhaps I should run gdb under debugger to see what is different when
we are getting ordinary breakpoint (which works for me) and hardware one
(which doesn't work as expected)
Andris
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