how to access memory

This is a discussion on how to access memory within the Tech Board forums, part of the Community Boards category; Hello, I'm trying to write a simple program to access a specific memory location (0x7FFF00000000). There is a device mapped ...

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    how to access memory

    Hello,

    I'm trying to write a simple program to access a specific memory location (0x7FFF00000000). There is a device mapped at that location. Of course, the OS gives seg fault and doesn't let me access the location. Is there a way to work around this problem? Thanks a lot!

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    ATH0 quzah's Avatar
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    Which OS? Most of them don't like you poking around where you shouldn't be.


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    solaris 10

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    ATH0 quzah's Avatar
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    clicky click Have fun.

    Quzah.
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    and the hat of wrongness Salem's Avatar
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    > There is a device mapped at that location.
    Then use the device driver to do the work for you.

    There's no way a protected OS like Solaris is going to let a mere user mode program anywhere near the hardware.

    > Is there a way to work around this problem?
    Yes, use the appropriate device driver.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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    But there is a problem with the device driver. I don't know how to tell the driver that the device is actually mapped at a memory location. How do I do that? Any hints? Thanks a lot.

  7. #7
    ATH0 quzah's Avatar
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    Oh, I don't know. You could perhaps read the link I pointed you at entitled "device driver tutorial", or maybe the one titled "Writing Device Drivers".


    Quzah.
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  8. #8
    and the hat of wrongness Salem's Avatar
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    > But there is a problem with the device driver.
    Tell the author.

    > I don't know how to tell the driver that the device is actually mapped at a memory location.
    Read the manual for the driver perhaps?

    At a rough guess, you (with your system admin hat on) update some OS startup script.

    At the point the driver is started, you provide some additional configuration parameter which is the location to look at.

    Moved to tech, as this seems more about Solaris admin rather than C programming.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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