[ECOS] CDL parent target+options?

Liviu Ionescu ilg@livius.net
Thu Apr 20 06:03:00 GMT 2000

> I belieave eCos was designed so the ROM and RAM apps could be
> different. Maybe it could be possible for targets that don't use this
> feature to build both ROM and RAM versions, but not for those that
> differ?

obviously we should not loose existing functionality, but we should make
things flexible enough to easily accommodate both type of
targets/development behaviours.

> The exactly the same objects files is the key issue. The target im
> using only recently used exactly the same object files. Before the
> objects were different. A ROM app would initialise the SDRAM
> controller where as a RAM app would not. You have to be careful when
> initialising the SDRAM controller since it can corrupt the contents of
> the RAM.

right, but the secret of my statement was "if carefully written" (... the
ROM configuration can be executed from RAM without source changes).

on most platforms the ROM entry point is hardcoded via a vector or some
fixed address structure, while RAM images can start from any address
(assuming the elf loader is functioning properly).

if so, you can easily have two different entry points, skipping useless (or
even harmful) init code when running from ram.

I'll try to solve this simultaneous RAM+ROM generation first by some more
elaborate cdl/make configurations, without having to change ecosconfig, and
let you know the results.



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