Re: Re: How to make crosstool support for VFP software fp format?

["YanXT Gpsign"<by_yanxt at gpsign dot com>]

----- Receiving the following content -----   
From:  Dimitry Andric   
Receiver:  by_yanxt   
Time: 2006-12-11, 18:19:04  
Subject: Re: How to make crosstool support for VFP software fp format?  
 
>YanXT Gpsign wrote: 
>>     Now I wonder if I can achieve it by compiling with a compatible-configured toolchain,  
>> at least vfp-softfp format-compatible toolchain...like crosstool-0.42 . Is this possible?  
> 
>It could be possible, but subtle differences between your toolchain and 
>MontaVista's might give other problems that are very hard to solve.  It 
>is simply much better to compile everything using the same toolchain. 
> 

    Yes, I could see that. So I tried to make the right toolchain for my target 
and send it to the 3rd party company to compile the lib  linked by my app.
the QUESTION now is to support the same VFP software fp format as the
one used by the 3rd party lib.

>That said, you need to make sure that your toolchain uses the same 
>floating point options as MontaVista's.  To see what MontaVista uses, 
>extract one of the .o files from libGPSEngine.a, e.g.: 
> 
>arm-9tdmi-linux-gnu-ar x libGPSEngine.a AGPS.o 
> 
>and then run objdump -p on it, to see what float options it uses: 
> 
>arm-9tdmi-linux-gnu-objdump -p AGPS.o 
> 
>You should get something like (but probably a little different): 
> 
>AGPS.o:     file format elf32-littlearm 
>private flags = 600: [APCS-32] [VFP float format] [software FP] 
> 

OK, I will test them ASAP. thanks for instructions.

>The "private flags" for *your* .o files should be exactly the same as 
>those from the MontaVista toolchain, then they can be linked together 
>without any problems. 

Does that good-to-go compilation  request my toolchain to support the same software fp format as
the format used by the  objects  in libGPSEngine?
so the final question (still hung before 3rd party company finishing the lib compilation) is gathered to be :
How can I make my crosstool support VFP float format as shown in private flags ?

thanks     

YanXT Gpsign, by_yanxt@gpsign.com   
2006-12-11