Re: [avr-gcc-list] FPLIB BUG: MEGA128

[Peter Jansen]

Peter,

> Sorry, I was out of action for a few days.
> I got the linking bit right by swapping:
> 
>     *(.text.*)  and    *(.text)
> 
> libc now sits pretty high up.
> Thanks for that one.
> 
> I tried your suggestion of changing mLPMRdZpp but that ran into the
> problem that ELPM is not defined for the device types under AVR5 (I
> assume your version will work, remember I'm working under windows which
> is pretty behind on patches).
> 
> Regardless of that little problem: I can think of 3 solutions to this
> fplib dilemma:
> 
> 1. Reserve an extra register for use inside mLPMRdZpp which then loads
> rampz. This would mean quite a bit of code changes in all the routines
> which use this macro. (ouch)

I don't think you need a register in the LPM macro, where this macro is
used and the Z register is loaded, put 
#if FLASHEND > 0xffff   ; or use BIG_CODE (defined in macros.inc)
        LPM_R0_ZPLUS_INIT (table_atan2)
#endif

Then you would have to do something when the table crosses the boundary
and Z is set to Z + Rad(lcount)
        
You could fix up the stuff in the fplib so that it uses the macros in
macros.h instead of defining its own.
 
> 2. Make the fplib tables relocatable so that they always load into the
> lower section of memory (much like the progchar strings in 'c') (how
> does one do that in assembler ?)

Where is this done?

> 3. Tell people to change the linker script so that fplib always links
> first (ish)

a bit ugly because someone will break it one day.

you could put them in there own section but thats also ugly.

Regards,

-- 
Peter Jansen
KlaxonIQA (formally Smart Container)
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AUSTRALIA
Ph 02 9209 4017
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