Re: Understanding relocation information

Kamil Konieczny <kaxosan@gmail.com>
Wed, 10 Mar 2010 03:44:25 -0800 (PST)

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Related articles
Understanding relocation information heyji2@gmail.com (AG) (2010-03-08)
Re: Understanding relocation information kaxosan@gmail.com (Kamil Konieczny) (2010-03-10)
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From: Kamil Konieczny <kaxosan@gmail.com>
Newsgroups: comp.compilers
Date: Wed, 10 Mar 2010 03:44:25 -0800 (PST)
Organization: Compilers Central
References: 10-03-016
Keywords: linker
Posted-Date: 10 Mar 2010 12:56:29 EST

On Mar 8, 11:28 am, AG <hey...@gmail.com> wrote:
> Hi,
>
> I am trying to understand how relocation information in PE/COFF files
> work, and I am half the way. For PE files, everything is in the .reloc
> section, and as far as I read the PE file specifications (provided by
> microsoft on their web site) I am fine. But for Object files, I don't
> really understand the specifications, and I would appreciate if
> someone could help me.
> [...]
> IMAGE_REL_I386_DIR32 0x0006 The target's 32-bit VA.
> IMAGE_REL_I386_DIR32NB 0x0007 The target's 32-bit RVA.
> [...]
> In these lines, I don't understand what the word "target" is referring
> to ? Neither do I understand the sentence themselves. For instance
> what should I do with "The target's 32-bit VA" ? How does it relates
> with my equation A = f(B) ?


for each relocation type, you can have different 'f' function
or you can have different target calc


spec should give details


> [The target is B, the address value that is supposed to be stored at
> A. Actually, it's more like A += f(B). -John]


there is Matt Pietrek old book with examples,


regards,
Kamil
[There is, of course, also my "Linkers and Loaders" which has a section on PE, but
perhaps not at the level of detail needed here. -John]


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