Hi Bohdan.

Would you be able to join next week Tech forum?

We can discuss the re-building of RTX binaries, flags, etc to make it compatible with everyone. Also, we may want to explore options and interest for other RTOSes.

Hope that helps
Thanks
Nick

From: Bohdan.Hunko--- via TF-M <tf-m@lists.trustedfirmware.org>
Sent: 04 March 2026 10:58
To: tf-m@lists.trustedfirmware.org <tf-m@lists.trustedfirmware.org>
Cc: nd <nd@arm.com>
Subject: [TF-M] Re: Short enums and short wchar
 

Hi all,

 

Any updates on this topic?

 

Best regards,

Bohdan Hunko

 

Cypress Semiconductor Ukraine LLC

Senior Engineer

CSS ICW SW INT BFS SFW

Mobile: +380995019714
Bohdan.Hunko@infineon.com

 

 

From: Bohdan.Hunko--- via TF-M <tf-m@lists.trustedfirmware.org>
Sent: Friday, 27 February 2026 14:23
To: Antonio.DeAngelis@arm.com; Anton.Komlev@arm.com; Nicola.Mazzucato@arm.com; tf-m@lists.trustedfirmware.org; David.Hazi@arm.com
Cc: nd@arm.com
Subject: [TF-M] Re: Short enums and short wchar

 

Caution: This e-mail originated outside Infineon Technologies. Please be cautious when sharing information or opening attachments especially from unknown senders. Refer to our intranet guide to help you identify Phishing email.

 

Hi all,

 

Thank you for the replies and suggestions.

 

I investigated the short enum and short wchar settings, and here is what I found.

 

At the moment, enum and wchar width settings are inconsistent across compilers:

 

 

 

Compiler

short enum

short wchar

ARM

YES

YES

GCC

YES

NO

IAR

NO

NO

CLANG

YES

YES

 

 

 

 

This inconsistency means that we cant choose uniformed flags for our crypto library.

 

I checked proposed solutions and I can agree that limited bandwith is also huge limitation for our team, thus we also will not be able to implement solutions like moving to freertos or building CMSIS rtos from sources during TFM build are.

 

As stated by Nicola:
> I rebuilt RTX not long ago and was not very difficult.

 

I believe this is the best solution here – just rebuild RTOS (with versions that are currently used (v5.5.0 for ARMCLANG and GCC compilers and v5.7.0 for IAR compiler)) with -fno-short-wchar and -fno-short-enums. And then remove short enum/wchar from compiler options in respective toolchain.cmake files in TFM.

 

If this change is acceptable I would gladly make changes in TFM cmake files and maybe @Nicola Mazzucato would be generous to provide rebuilt for the libraries?

 

 

Best regards,

Bohdan Hunko

 

Cypress Semiconductor Ukraine LLC

Senior Engineer

CSS ICW SW INT BFS SFW

Mobile: +380995019714
Bohdan.Hunko@infineon.com

 

 

From: Antonio De Angelis <Antonio.DeAngelis@arm.com>
Sent: Friday, 27 February 2026 11:08
To: Anton Komlev <Anton.Komlev@arm.com>; Nicola Mazzucato <Nicola.Mazzucato@arm.com>; Hunko Bohdan (CSS ICW SWE INT BFS SFW) <Bohdan.Hunko@infineon.com>; tf-m@lists.trustedfirmware.org; David Hazi <David.Hazi@arm.com>
Cc: nd <nd@arm.com>
Subject: Re: Short enums and short wchar

 

Caution: This e-mail originated outside Infineon Technologies. Please be cautious when sharing information or opening attachments especially from unknown senders. Refer to our intranet guide to help you identify Phishing email.

 

There were mentions of using FreeRTOS, I believe it’s a good option as well, being it a widely adopted solution in the ecosystem. But we can discuss further in a tech forum.

 

Thanks,

Antonio

 

Sent from Outlook for Mac

From: Anton Komlev <Anton.Komlev@arm.com>
Date: Thursday, 26 February 2026 at 20:37
To: Nicola Mazzucato <Nicola.Mazzucato@arm.com>, Antonio De Angelis <Antonio.DeAngelis@arm.com>, Bohdan.Hunko@infineon.com <Bohdan.Hunko@infineon.com>, tf-m@lists.trustedfirmware.org <tf-m@lists.trustedfirmware.org>, David Hazi <David.Hazi@arm.com>
Cc: nd <nd@arm.com>
Subject: RE: Short enums and short wchar

Let’s take this topic to the Tech Forum.

Personally, I’d prefer using prebuilt binaries in tf-m-tests and avoiding fetching the CMSIS repo if possible since it’s quite heavy.

As I recall several RTX binary configurations are needed to cover different compiler options.

 

Thanks,

Anton

 

From: Nicola Mazzucato via TF-M <tf-m@lists.trustedfirmware.org>
Sent: Thursday, February 26, 2026 5:08 PM
To: Antonio De Angelis <Antonio.DeAngelis@arm.com>; Bohdan.Hunko@infineon.com; tf-m@lists.trustedfirmware.org; David Hazi <David.Hazi@arm.com>
Cc: nd <nd@arm.com>
Subject: [TF-M] Re: Short enums and short wchar

 

I rebuilt RTX not long ago and was not very difficult.

Though I did not change the flags, we my need to look into that.

 

It's also possible that TF-M could benefit from a more up-to-date version of RTX.

 

Not sure what others think.

Maybe a discussion topic for the next Tech Forum?

 

Thanks

Nick

 

From: David Hazi via TF-M <tf-m@lists.trustedfirmware.org>
Sent: 26 February 2026 16:24
To: Antonio De Angelis <Antonio.DeAngelis@arm.com>; Bohdan.Hunko@infineon.com <Bohdan.Hunko@infineon.com>; tf-m@lists.trustedfirmware.org <tf-m@lists.trustedfirmware.org>
Cc: nd <nd@arm.com>
Subject: [TF-M] Re: Short enums and short wchar

 

Hi all,

 

https://github.com/ARM-software/CMSIS-RTX/releases/tag/v5.9.1

Prebuilt images are in the RTX_Lib.tar.bz2 file.

 

There were discussions about switching to FreeRTOS, is this still an option?

 

Dávid

 

 

From: Antonio De Angelis via TF-M <tf-m@lists.trustedfirmware.org>
Date: Thursday, 2026. February 26. at 17:22
To: Bohdan.Hunko@infineon.com <Bohdan.Hunko@infineon.com>, tf-m@lists.trustedfirmware.org <tf-m@lists.trustedfirmware.org>
Cc: nd <nd@arm.com>
Subject: [TF-M] Re: Short enums and short wchar

Hi Bohdan,

 

Prebuilt RTX libraries were provided by the CMSIS project but I believe that now they have stopped distributing them. Using the prebuilt libraries at the beginning of TF-M was just a practical choice, I’d very much welcome a contribution to build RTX from source as part of the NS code. Do you think you can work towards that? Currently our bandwidth is limited to spend some engineering time on that but would very much appreciate any contributions.

 

Thanks,

Antonio

 

Sent from Outlook for Mac

From: Bohdan.Hunko--- via TF-M <tf-m@lists.trustedfirmware.org>
Date: Thursday, 26 February 2026 at 15:58
To: tf-m@lists.trustedfirmware.org <tf-m@lists.trustedfirmware.org>
Subject: [TF-M] Short enums and short wchar

Hi all,

 

Currently TFM specifies -fshort-wchar and -fshort-enums

 

There previously was a discussion about this in https://lists.trustedfirmware.org/archives/list/tf-m@lists.trustedfirmware.org/thread/HCUXA72SZHSCXIEJSMH4RACJLMOXAQC6/

 

The decision was to remove these flags – which was done in https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/6186

But then fix was reverted in https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/6349 because:

               Removing the -fshort-wchar flag will cause link error with

                    RTX library while using armclang and debug mode.

 

Now we faced same issue when linking some of our prebuilt crypto libraries.

Since RTX libraries ware prebuilt by TFM maintainers (prebuilt RTX libs are not part of CMSIS RTX) – I believe it is better to rebuild them without -fshort-wchar and -fshort-enums and remove these flags in TFM.

Does TFM team still have a possibility to rebuild these RTX libs? Does this change make sense to TFM community?

 

           

 

Best regards,

Bohdan Hunko

 

Cypress Semiconductor Ukraine LLC

Senior Engineer

CSS ICW SW INT BFS SFW

Mobile: +380995019714
Bohdan.Hunko@infineon.com