`range check failed` because type `Natural` is used for address values

[luzidchris]

Some of the SVD files in CMSIS_SVD lead to CONSTRAINT_ERROR exceptions because type Natural is too small to store address values.
This can be reproduced for example with M1AGL.svd.

The following error is raised by svd2ada:

raised CONSTRAINT_ERROR : base_types.adb:218 range check failed

In my system (linux 64-bit), type Natural has a max value of 2147483647, i.e. 0x7FFFFFFF. As a result of this, svd2ada fails to process address or size values which are greater than this upper limit.

[Fabien-Chouteau]

Thanks @luzidchris, do you know if SVD defines limits for the types of those values?

[luzidchris]

Hi,

I've unfortunately not found any constraints. I assume this is not defined by SVD format because memory mapping is pretty target-specific.

In my case, the Constraint_Error was raised while calculating an absolute address and therefore my initial idea was to align data types to Unsigned (defined by Base_Types if I remember correctly). The type is already used for some of the address-related calculations, it's in svd2ada. And it should ensure that calculations work for all (or at least 99,9999 %) of the existing target architectures (incl. 64-bit).

[Fabien-Chouteau]

Maybe we should switch to the Ada2022 Big_Numbers for those values.