Linker script

[Daniel Lidsten]

> > 
> > I have a special problem that has to do with the linker 
> script. In my 
> > application i want to add a CRC value to the binary image so that i 
> > can check the code segment for errors during runtime. I 
> cannot put the 
> > CRC over the entire image since some segment are changing during 
> > execution so instead i want to calculate it based on the 
> text segment 
> > only. However, the segment is of different size each time i 
> link which 
> > means that i have to communicate the size to the CRC calcualtion 
> > routine. I think that it should be done in the linker script by 
> > something like
> > this:
> > 
> >     .text   0x5000  :      { _stext = .; *(.text*) *(.gnu.warning)
> > *(.gnu.linkonce*) *(.init) } >  ram  _etext = .;  PROVIDE
> > 
> > The text segment specifies where the end is in the variable _etext.
> > 
> > I need the above value to be place on a fixed location by something 
> > like
> > this:
> > 
> > .TextEnd   0x004DFFFC :      { etext }
> > 
> > The above dones work but can any see a way for this to work?
> 
> The address of _etext should be a global symbol that you can 
> access directly in your 'C' program. You need to add a definition like
> 
> extern char _etext
> 
> And then you can take the address of it
> 
> I.e.
> 
> ptEndOfText = &e_test;
> 

I think you misunderstod my problem here. It is not a c program that
shall access this variable, i want the value of etext to be place on a
fixed adress of the binary image. This is because a let another program
interpret the binary image and calcualte a checksum on it i.e i need to
know the value of etext data without running the program.

Regards, Daniel Lidsten

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