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Conditional watchpoints

Question asked by SCOTT MILLER on Aug 8, 2018
Latest reply on Aug 12, 2018 by Erich Styger

I'm looking for some information on how watchpoint conditions are supposed to work in MCUX - there's very little at all on watchpoints in the documentation, and nothing about conditions.  At McuOnEclipse, Erich has an article discussing them a little, but there's no information on how they work.


What I'm hoping to accomplish is to find out when a particular pointer is getting set to NULL.  I can catch writes to it easily enough, but most of the writes are going to be normal and I might have to wait through hours of normal operation to catch the problem.  If I add a condition px == 0, the system runs extremely slowly and gdb crashes when I try to pause it.  I've tried both an LPC-Link2 and a Cyclone ACP.


What I assume  is happening is that the debugger is having to stop and check the memory contents constantly.  The watchpoint itself has to be implemented by a hardware comparator and the manual says as much, but does the hardware support value comparisons or just address matches?  Is there a way I can get this thing to run at a reasonable speed while still checking for nulls?