Feature request: fill memory range with address data

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While troubleshooting memory issues, having address data written into each memory location can be very helpful (which I believe DiagROM at startup for memory it will use). However, sometimes the memory to be investigated contains other data (such as, I think, when running DiagROM in Fast RAM but wishing to test Chip RAM, or after an interrupted memory test). Could DiagROM have a separate function for filling a specified memory range with address data? I guess the range would need to be longword-aligned.