Question

I m pretty sure this is possible but I m not sure how to go about it. I m very new to building with GCC in general and I have never used FreeRTOS, but I d like to try getting the OS up and running on a TI ARM Cortex MCU but with a slight twist: I d like to get it up and running with Pascal. I m curious:

Is this even possible to get work? If not, the next issues are kind of moot points.
From my Delphi days, I vaguely recall the ability to access functions in C libraries. I m wondering if I would have access to the C routines in FreeRTOS.
If I use the GCC version (preferable) would I be able to debug using OpenOCD on the target? I m not quite sure how debug symbols work and if it s more or less language agnostic (hopefully, in this case).
As kind of a bonus question a bit outside the scope of the original query, can I simulate FreeRTOS on an x86 processor (e.g. my development PC) for easier debugging during development? (With a Pascal program, of course..)

I haven t found any documentation on achieving this, so hopefully someone here can shed some light! Any resources would be most helpful. Like I said, I m very new to this kind of development. I m also open to suggestions if you think there is a better alternative.

FYI, my preferred host configuration would be something similar to:

Linux (Ubuntu/Debian)
Eclipse IDE for development, unit testing, and hopefully simulation / debugging
OpenOCD for target debugging
GNU Pascal + FreeRTOS on target

Answer 1

FreeRTOS is C source code, so like you say you would have to have some mechanism for linking C with your Pascal programs. Also, FreeRTOS relies on certain registers to be used for things like passing a parameter into a task (as a hypothetical example, the task might always expect the parameter to be in register R0) so you would have to ensure the ABI for the C compiler and the Pascal compiler was the same - or have your task entry in C then have it call a Pascal function (very nasty). Then there is the issue of interrupts, calling inline macros, etc. I would say this would be extremely difficult to achieve.

Answer 2

Both GNU Pascal and Free Pascal support linking to C (gcc) and ARM, as well as calling pascal code from C etc. Writing a header and declaring the prototypes with cdecl is all there is to it.

Macros are a bit bigger problem. Usually I just rewrite them to inline functions (what they should have been anyway). Except for the macro/header issue, the problems are more compiler specific functionality (which you also would have a problem with when porting from one C compiler to the next)

If you prefer TP/Delphi dialect, Free Pascal is the better choice.

I run my old Delphi code fine on my sheevaplug.

Answer 3

There is already an example for FreeRTOS/GCC/OpenOCD on a TI Cortex-M3 (was Luminary Micro Cortex-M3). Be aware though that this is a really old example and both the Eclipse and OpenOCD versions used are out of date.

Although there is an Eclipse project provided, the project is configured as a standard make (as opposed to a managed make) project, so there is a standard makefile that can be just as easily executed from the command line as from within Eclipse.

http://www.freertos.org/portLM3Sxxxx_Eclipse.html

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