question about rtems compiler
chrisj at rtems.org
Thu May 10 07:25:14 UTC 2012
On 9/05/12 10:10 PM, Luca Cinquepalmi wrote:
> I have no error... I'd just like to know the difference bewtween a
> simple C source code (with main function)
> and rtems structured one... thanks.
Traditionally most embedded systems did not support 'main', RTEMS
included. The boot monitor passes control to the BSP entry point and
this initialises various resources then starts RTEMS running. The C API
provides support for initialisation tasks that can be started. This
approach makes 'main' difficult.
These days RTEMS does provide support for 'main' if the BSP supports it.
There is code in the BSP shared area that provides a default 'Init'
symbol as weak. This ties in with confdefs.h support and the runtime
configuration of RTEMS which assumes the entry point is a single
initialisation task called 'Init'. If the weak Init support is built by
your BSP you can just provide 'main' and it will be called.
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