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I need a disassembler for AMD 188

Discussion in 'Embedded' started by Coder, May 20, 2006.

  1. Coder

    Coder Guest

    Hi,
    I need a disassembler for a Amd-188 microcontroller.

    Please send me some links for a good one.

    Thanks.

    S.L.
     
    Coder, May 20, 2006
    #1
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  2. Coder

    larwe Guest

    Ada Pro.
     
    larwe, May 21, 2006
    #2
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  3. Coder

    larwe Guest

    (whoops) _Ida_ Pro.
     
    larwe, May 21, 2006
    #3
  4. Is that an 80188? Then anything that claims to be 8086 compatible
    will work.
     
    Roberto Waltman, May 21, 2006
    #4
  5. Coder

    larwe Guest

    Yes. Ida Pro is very nice, though. Saves considerable time in
    reverse-engineering (vs. say DEBUG.COM :)
     
    larwe, May 21, 2006
    #5
  6. Coder

    Coder Guest

    I have IDA pro but when I try to decompile IDA ask for the Starting
    point,
    I don´t know exactly the starting point and when I specify the
    starting the result code do not has sense, that say that I have
    specified a wrong Address.

    How Can I know where the program start?
    AM188 is a microcontroller from AMD.

    Thanks.
    S.L
     
    Coder, May 27, 2006
    #6
  7. Coder

    John B Guest

    Coder scrobe on the papyrus:
    Read the data sheet and find out about the reset address, then you will
    know where to start from.
     
    John B, May 28, 2006
    #7
  8. Coder

    Tauno Voipio Guest


    The 80186 family processors start at 16 bytes below the
    top of address range, here: 0xffff:0. Try 16 bytes below
    the top of your PROM.
     
    Tauno Voipio, May 28, 2006
    #8
  9. Coder

    Coder Guest

    The system uses a EPROM 27C4001 4096kB.
    So I will 4096kb - 16b = 4095984b
    This is the address of starting .
    And How can I find the Check Sum procedure.

    Thanks.
     
    Coder, May 28, 2006
    #9
  10. Coder

    Gob Stopper Guest

    OK...

    - You started asking for a disassembler. You got connected up with one.
    It was unclear whether you were aware that the AMD and Intel
    architecture are the same.

    - Then you asked where the program starts. This tells me that you are
    not especially familiar with the architecture at all.

    - Then you asked where the checksum procedure is. It's not necessary
    that a checksum procedure exists. If it does, it could be anywhere in
    the address space of the processor. You're not going to find it without
    a lot of work.

    There are many people in this newsgroup who make a living doing exactly
    the kind of work that you appear to be trying to avoid.

    I think you have two paths:

    1) Get some books on the Intel 8086 architecture and read them, cover to
    cover. Start at 0xFFFF:0 and look at what's there. It's probably a jump
    to somewhere else. Look there and follow the code.

    2) Pay someone to reverse-engineer whatever your target is, in which
    case, they'll start at 0xFFFF:0, etc.

    GS
     
    Gob Stopper, May 29, 2006
    #10
  11. Coder

    Coos Haak Guest

    Op 28 May 2006 13:40:16 -0700 schreef Coder:
    First, learn that 1 kb is not 1000, it equals 1024.
    So 4096 Kb - 16 = 4194288
    But doing it hexadecimal is way simpler:
    4096 Kb = 0x400000, minus 16 is 0x3FFFFF0

    But I think Tauno has it right, the reset address still is FFFF:0000
    because the 188 is a 16 bit processor with 20 bit address. At least it
    starts running like one, the Pentia still do this. Later on the latter
    switches to protected, 32 bit mode. I think the 188 won't.
     
    Coos Haak, May 29, 2006
    #11
  12. Coder

    Coder Guest

    I need a sugestion of How can I find the part of code I looking for.

    I´m using IDA but I dont know if the code is correct. I have specified
    to IDA where start each procedure.

    I think that if I specify the starting point it woul be enough.

    The end of the binary file has:
    0007FFF0h 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0007FFF0h EA 00 00 F0 FF 00 00 00 00 00 00 00 00 00 00 00

    but this address is with 00 and the next line has code:
    0000FFF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    00010000 C8 06 00 00 1E B8 3C 48 8E D8 C6 46 FF 00 C7 46,

    I think that the program begin here but I need to press ¨C¨ for each
    procedure.
     
    Coder, Jun 5, 2006
    #12
  13. Coder

    Coos Haak Guest

    Op 5 Jun 2006 15:07:47 -0700 schreef Coder:
    This is a far jump to address FFF0:0000
    This is address: 0000:FFF0 so not the same as above.
    This can not be the beginning of a program, it starts with an ENTER
    instruction. It's the beginning of a procedure/subroutine.
    I don't know IDA and I have no idea what the C-key does.
    I can't help you here. Read the documentation that without a doubt comes
    with IDA ...
     
    Coos Haak, Jun 6, 2006
    #13
  14. Coder

    Coder Guest

    Can you suggest me a decompiler for 80188.
     
    Coder, Jun 7, 2006
    #14
  15. Coder

    Coos Haak Guest

    Op 7 Jun 2006 14:43:53 -0700 schreef Coder:
    Since the early days of MS-DOS up to Windows XP, DEBUG is included.
    SYMDEB would do, or Turbo Debugger (Borland)
    There must exist much newer debuggers, I don't know ;-)
     
    Coos Haak, Jun 8, 2006
    #15
  16. ??? - Do not expect to get very different answers from what you got
    when you asked the same question two weeks ago. (OK, almost the same
    question. I will ignore the issue of how a 'decompiler' is different
    from a 'dissasembler')
    From the lowly debug.com that came with older versions of MS-DOS, to
    Ida-Pro, that you claim you have. You must learn to use it, and you
    must know the architecture and instruction set of the '188 to make
    sense of any dissasembler output. Nobody can do this for you.
     
    Roberto Waltman, Jun 8, 2006
    #16
  17. Coder

    Tauno Voipio Guest


    There's no such thing - there is plenty of the information
    of the original source code lost when it has been translated
    (compiled, assembled and linked). There's no way to re-generate
    that information reliably fromthe binaries.

    You can help the tedium a little by using a good dis-assembler
    in an intelligent way. But expect the de-compilation to be
    a task resembling solving a giant Sunday paper crossword puzzle.

    (been there - done that)
     
    Tauno Voipio, Jun 8, 2006
    #17
  18. Coder

    Coder Guest

    This program is for Arcade machine, so I didn´t think it could be
    disassembled with
    debug.com .

    The system uses a EPROM 27C4001 4096kB
    the max address is 0007FFF0h
    in this line > 0007FFF0h EA 00 00 F0 FF 00 00 00 00 00 00 00 00 00 00
    00

    This is a far jump to address FFF0:0000 so this address is not the
    memory space.
    What is going on here?

    Thanks.
     
    Coder, Jun 8, 2006
    #18
  19. Coder

    Gob Stopper Guest

    I'll tell you what, before you ask any more questions, answer this question:

    FFF0:0000 is a 32 bit address, the 80188 has a 20 bit address bus. How
    does the 32 bit logical address get converted to a 20 bit physical address?

    If you get the correct answer, we'll know that you've spent at least a
    little time understanding the processor. If you get the wrong answer,
    we'll know that you're probably a fool and needs to do his own homework.

    GS
     
    Gob Stopper, Jun 8, 2006
    #19
  20. Coder

    Jim Stewart Guest

    He still needs to do his homework, but his address may
    still be valid in a 20-bit address space. It's common
    to represent x86 addresss as segment:eek:ffset which, in
    this case would be an absolute address of 0xFFF00.
     
    Jim Stewart, Jun 9, 2006
    #20
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