Re: [avr-gcc-list] gcrt1.S and the __mcucr__

[Kang Tin LAI]

Hi,

Thank you very much. Surprise me that excellent information.

Beside of MCRCR and WDTCR, I don't find any code for zeroing the bss,
this is another causation makes my code die. Section bss is supposed to
be zeroed by compiler according to language standard.

Kang Tin LAI <address@hidden>

Joerg Wunsch wrote:
> 
>  Kang Tin LAI <address@hidden> wrote:
> 
> > I found that the weak __mcucr__ and its setup codes were removed from
> > gcrt1.S. I use defsym ld option to setup the MCUCR for external SRAM
> > access.
> 
> Please see the FAQ:
> 
> http://freesoftware.fsf.org/download/avr-libc/doc/avr-libc-user-manual/FAQ.html#faq_startup
> 
> --
> J"org Wunsch                                           Unix support engineer
> address@hidden        http://www.interface-systems.de/~j/


"Theodore A. Roth" wrote:
> 
> Read this and then init MCUCR in .init3:
> 
> http://freesoftware.fsf.org/download/avr-libc/doc/avr-libc-user-manual/mem_sections.html
> 
> Hope that helps.
> 
> Ted Roth
> 
> On Thu, 5 Sep 2002, Kang Tin LAI wrote:
> 
> :) Hi,
> :)
> :) My project which is OK with libc 20020203 and gcc 3.0.x, but failed with
> :) 20020630.
> :)
> :) I found that the weak __mcucr__ and its setup codes were removed from
> :) gcrt1.S. I use defsym ld option to setup the MCUCR for external SRAM
> :) access.
> :)
> :) In the gcrt1.S during startup, initialized data are copied to SRAM from
> :) flash and then the bss zeroing. If MCUCR is not setup for external SRAM
> :) access prior to data moving, and the length initialized data + bss
> :) exceeds internal SRAM, then it is a serious problem.
> :)
> :) Kang Tin LAI <address@hidden>
> :) avr-gcc-list at http://avr1.org
> :)
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