exception_set_exclusive_handler & ISRs

[nstansbury]

I have an initial Platform.IO library of a multi-core "micro-kernel" for the Pico - Postman::Pico Task Manager based on the official SDK (v1.4) that I am trying to port over to work with the arduino-pico core, but I'm not able to set the Systick and SVC ISRs via exception_set_exclusive_handler(SYSTICK_EXCEPTION, ..) and exception_set_exclusive_handler(SVCALL_EXCEPTION, ..) as they have both already been installed.

Reading some other threads: ThreadX Porting they seems to suggest this maybe something to do with how the Pico SDK is included in arduino-pico and __isFreeRTOS.

Could I get some pointers on what might be happening, as I'd just assumed I'd have full access to H/W via the SDK but this appears not to be the case.

[earlephilhower]

The SYSTICK is used to handle cycle counting in the plain core. FreeRTOS will use it for its task swapping. You could hack and remove cycle count support in non-freertos mode, I suppose. See cores/rp2040/RP2040Support.h