Re: PIC question

[Johnny Billquist <bqt%softjar.se@localhost>]

Martin Husemann wrote:
> I'm new to vax asm and have not been fully assimilated, it seems - I have
> some asm code that is not PIC and so when compiled into a .so dies due
> to .text relocs. (Linked static it all works)
>
> It does kindof Duff's device in asm - there is an unrolled loop starting
> at .Loop and a jump with offset into the loop is calculated in %r5, then the
> code does:
>
>         jmp     .Loop(%r5)
> .Loop:  ...
>
> This causes a 32bit relocation for the .Loop address inside the
> indirect jump with offset instructions.
>
> What is the pic way to do this? Some trick? There doesn't seem to be a br +
> register offset instruction.
>
> Or along the lines of:
>
>         addl2   %pc,%r5
>         add     .Loop - ., %r5
>         jmp     (%r5)
> .Loop:  ...
>
> (but the .Loop-. is not accepted by gas)
>
> ?

Maybe a stupid solution, and I'm sure there is a more kosher one, but...

        addl2   %r5,%pc

should do the trick. :-)

        Johnny

--
Johnny Billquist                  || "I'm on a bus
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