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#685 Debugger: visualization problem (jmp)

fixed_in_v2.2
closed
nobody
Debugger (99)
5
2012-10-15
2003-09-12
Martin Candurra
No

0008:c0001987 (unk. ctxt): nop ; 90
<bochs:3> s
Next at t=42386115
0008:c0001988 (unk. ctxt): jmp c0001a87 ; ebfd
<bochs:4> s
Next at t=42386116
0008:c0001987 (unk. ctxt): nop ; 90

If you see the address where the "jmp" instruction "is
going to jump" you can see a interpretation problem of
the debugger. The op code is ebfd (what is a relative
jump). The "fd" is meaning a sort of complement and is
the same that "-2". My code is:

pepe: nop
jmp pepe

so, the jmp command jumps 2 bytes back into the code.
So the problem is the visualization. It must be 1987, but
the debugger shows 1a87 because he add to the actual
ip address the "fd", part of the relative jump.

I apologize for my poor english

Discussion

  • Logged In: YES
    user_id=487634

    This problem is already fixed.
    As I understood it is disassembler problem which didn't
    handle correctly signed immediate for jmp instructions, This
    is already fixed.
    Now we have different jump visualization problem reported in
    bug report #1170614 (relative jumps/calls wrong in debugger
    ) ;)

    Stanislav