Re: 0xdff058
"Is it sad that I remembered my favourite hardware register, 0xdff058, almost quarter of a century later without having to google?"
Don't worry about it - I can still remember some 6809 op-codes even though it had thousands of them.
( I too remember my A1000 with affection even though compiling Lattice C was a disk swapping operation until I got a hard drive)