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Re: m68k reloc types
Roman Zippel <firstname.lastname@example.org> writes:
> On Mon, 16 Aug 2004, Andreas Schwab wrote:
>> Roman Zippel <email@example.com> writes:
>> > One issue that really confused me at first is that some m68k pic reloc
>> > types do something completely different than their i386 counterparts.
>> The m68k has different capabilites than the i386.
> The capabilities are actually quite similiar, i386 has no direct pc
> relative addressing mode, but the trick used has the same effect from the
> linker pointer of view. What different kind of capabilities do you have in
That the m68k can address directly relative to the pc obviates the need
for the klugey way the GOT register is set up on i386.
> That R_68K_GOT32O is the same as R_386_GOT32 is not a little confusing?
> What should we call R_386_GOTOFF if we wanted to implement it for the m68k
There is no corresponding relocation defined for m68k, because it is not
>> > AFAICS it should be possible to fix this, existing binaries may not break
>> > of course, but I think it should be possible to just rename this
>> > within binutils.
>> Why do you need to rename them? The names are defined by the ELF specs.
> Which I don't have access to. A quote of relevant parts would be helpful
The m68k processor supplement is only available on paper, and out of print
now. I have no information on any online reference, but I have a paper
copy of it.
> (especially the difference between R_68K_GOT32 and R_68K_GOT32O).
The first is a pc-relative offset to the GOT, the latter is the offset
from the start of the GOT.
> Could you please explain the rationale behind the _GLOBAL_OFFSET_TABLE_
> checks in elf32-m68k.c? Unfortunately the cvs history doesn't go that far.
This is a special symbol that always points to the start of the GOT.
Andreas Schwab, SuSE Labs, firstname.lastname@example.org
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."