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Powerpc IRQ handling breaks strict EABI compliance
- Date: Thu, 13 Feb 2003 14:44:31 -0600
- From: joel.sherrill at OARcorp.com (Joel Sherrill)
- Subject: Powerpc IRQ handling breaks strict EABI compliance
Till Straumann wrote:
> Sergei Organov wrote:
> > Joel Sherrill <joel.sherrill at oarcorp.com> writes:
> > [...]
> >>I agree with your analysis. The r2/r13 init needs to happen much earlier
> >>than constructors can be executed.
> >>So the simplest solution (to me anyway) is:
> >> + bsp assembly startup initializes r2/r13 possibly using common code
> >> derived from __eabi without the call to _init.
> >> + call _init from _Threaad_Handler
> >>Longer term, we can switch the toolset from non-EABI to EABI if that is
> > I also think this is the simplest solution. The only question remained is if
> > the __eabi() is GPLed, and if so, if the "common code derived from __eabi"
> > could be put into RTEMS ;-)
> I don't like the idea of replicating (parts of) __eabi(). I'd rather
> use the original. Note that if we cant change the way it branches
> to __init, there's a simple fix to this:
> add ecrti_rtems/ecrtn_rtems startup files who are put after
> ecdri/ecdrtn. ecrti_rtems.S could simply do
> .section ".init","ax"
> .align 2
> lwz 0,20(1)
> mtlr 0
> addi 1,1,16
> stwu 1,-16(1)
> mflr 0
> stw 0,20(1)
> This snippet makes __init() a no-op and creates a new entry
> point _init for use by the ThreadHandler (remember, ThreadHandler
> calls _init anyways). Alternatively, a special symbol may be used.
> All the BSP has to do now is calling __eabi() at an early stage.
Very clever. :) I like this one. Give it a try.
> -- Till
Joel Sherrill, Ph.D. Director of Research & Development
joel at OARcorp.com On-Line Applications Research
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