Cortex-M: Temptative fix for watchpoints so they work on ARMv8-M cores (eg Cortex-M33)

[mean00]

Detailed description

The DWT block is different on Arm V8m compared to older revisions. As a result the watchpoint(s) function are not working.
The patch adds a second path dealing with the ArmV8m .
Tested on cortex m33, check setup watch some_variable (such as xTickCount on freeRtos)

• without the patch, does not stop
• with the patch, does stop as expected

It was partially tested, i dont have other chip with that DWT block. Only test write watchpoints.
As far as i can tell, watchpoints are still working with older chips (cortex M4)

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (see Building the firmware)
• It builds as BMDA (see Building the BMDA)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

[dragonmux]

This is looking really good and complements our own work on ARMv8-M debug on the fix branch fix/adi-structural-cleanup. We'd love to get this merged for v2.0 so if you can take care of the small number of review notes (most are to do with nomenclature and we don't think will take that long to deal with as it's mostly just find-replace stuff), we'll get this merged ASAP.

[mean00]

Thank you for the comments, will update it as soon as i can

[mean00]

I think i took all the comments into account.
If it's ok i'll squash the commits
Thank you

[dragonmux]

Yeah, looks good to us. Please let us know once you've squashed the commits down (noting that there should not be a space between the suffix and its' :, so cortexm: not cortexm :) and we'll get this merged.

Thank you for the contribution! Nicely done.

[mean00]

Should be okay now
Thank you