[En-Nut-Discussion] RFQ: Changes to Nut/OS to support AT90CAN128

[Henrik Maier]

Harald Kipp wrote:
> Henrik,
> 
> IMHO, it's a good idea to create new functions named NutStack*().

I put them into CVS yesterday and they will be used if the macro 
NUTMEM_STACKHEAP is defined. Corresponding entries have been added to 
the configuration scripts.

> Why not use NutStack*() for all targets? In the future we
> may be able to optionally configure a separate memory area
> for the stack. Even some ATmega128 based systems may benefit
> from using fast internal RAM.

At this stage the NutStack*() calls are only used if NUTMEM_STACKHEAP is 
defined to keep context switching as fast as possible for architectures 
which don't need a special stack area.

>> * How to incorporate the linker flag -Wl,-Tdata=0x801100 into 
>> nutconf's build model. All apps compiled for the AT90CAN128 require 
>> relocation of .data/.bss into the external RAM.
> 
> b) or implement a new Makefile macro for additional
> linker options. In this case, nutsetup and the Lua scripts
> have to be modified.

I amended the app/Makedefs.avr-gcc file for the AVR architecture to 
relocate the data segment if DATA_SEG is set. Corresponding entries have 
been added to the configuration scripts. Not a perfect solution but at 
least a starting point.

Henrik