[ECOS] Newbie: looking for minimal systems (HAL only) examples

Bart Veer bartv@ecoscentric.com
Thu Apr 29 15:33:00 GMT 2004

>>>>> "Daniel" == Daniel Lohmann <daniel.lohmann@informatik.uni-erlangen.de> writes:

    Daniel> I have just started experimenting with ECOS, so my
    Daniel> questions might be somewhat simple:

    Daniel> How to create an application, that uses a minimal ECOS
    Daniel> system?

    Daniel> I started with the configuration tool and created a
    Daniel> configuration of a minimal i386-elf project that contains
    Daniel> just the HAL and some surrounding support functionality.
    Daniel> However, how do I link this to some application code?

Just link your application in the same way as with any other eCos
configuration, as per the User's Guide. You don't need to do anything
special for a minimal eCos configuration.

    Daniel> Which is the start address or symbol of the new system?

At the end of system initialization the HAL will call cyg_start(),
with interrupts still disabled. You can provide this cyg_start()
function, and probably should do so when using the minimal template.
Typically that is what the various eCos tests do, so you can look at
those. If the application does not provide cyg_start() then there is a
default implementation in the infra package, but that is intended
primarily for more complicated scenarios where you need main() running
in its own thread.

    Daniel> And how do I create a boot floppy disk image?

I assume this is for a PC target. Take a look at
hal/i386/pc/current/cdl/hal_i386_pc.cdl for the custom build step
which generates a RedBoot boot floppy image. Alternatively do a
RedBoot build and look at the last few commands executed.


Bart Veer                       eCos Configuration Architect
http://www.ecoscentric.com/     The eCos and RedBoot experts

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