I'm using "B_CALL _InsertMem" to give myself 12,000 of free ram starting at $9D95, but apparently I've got some bugs where I'm writing to address beyond that range. I know what the problem is, but I don't know where the problem is. (I'm using a routine to copy tiles from a master set to RAM, but it looks like I've got a few tile tables with invalid data in them, causing the tile copy routine to copy them past my allocated 12,000 data.) Is there a way to ask WabbitEmu to "break" upon a write to a RAM location within a range (from $C000-$E000 for example) rather than manually setting a watchpoint for every, single RAM address in that range?

The short answer is "yes." It has been a long time since I've used wabbitemu, but I think you need to set the breakpoint using the menu, and then you have the option of defining a memory range and whether you want to break on some combination of read/write/execute.

I don't think WabbitEmu can set a watchpoint for a memory range unfortunately, which would be a super useful feature.

Obligatory "not WabbitEmu", but even though ranges of memory watchpoints are not exposed in jsTIfied, I'm sure that we could figure out the relevant Javascript to run to create them.

In any case, I went to plan "B" and just added some debug-code into my program.