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RAM dump format for Swiss Micros DM41s?
06-18-2017, 08:44 PM
Post: #1
RAM dump format for Swiss Micros DM41s?
Hi! Long time user, intermittent collector, intermittent visitor to the forums over the years. Couldn't resist getting a Swiss Micros DM41L recently (very happy!). Thanks to all for participating in the other DM41 discussions; it both helped me confirm my decision to purchase and get the serial communications working quickly.

Was wondering if anyone knew a few things about the RAM dump format off of the serial port. It's obvious that the first block are the memory contents as registers, each separated by spaces --- but why start at location 0x8? And why are some, but not all, processor registers dumped? (I don't see D, E, and F, for example).

Just curious.
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06-21-2017, 11:34 AM (This post was last modified: 06-21-2017 12:37 PM by grsbanks.)
Post: #2
RE: RAM dump format for Swiss Micros DM41s?
Any group of 4x7 bytes that is all zeros is omitted from the dump, so if you don't see the lines 0x00 or 0x04 then there's nothing in there Smile

The other registers aren't dumped because they don't exist. They are part of the Saturn CPU register set, and the Saturn CPU is an evolution of the Nut processor in the '41.

BTW, I'm working at full speed on a tool to decode/encode raw files for the soon-to-come DM42 right now but a lot of this can also be used for the DM41 since the DM42/HP-42S uses an extended version of the DM41/HP-41C instruction set.
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06-22-2017, 04:05 AM
Post: #3
RE: RAM dump format for Swiss Micros DM41s?
*facepalm*. Of course about the other registers. Sorry --- I've been putting together a tech talk about the Saturn CPU for some folks at work, and I'm conflating architectures. Thanks!

Great idea skipping the null locations --- hadn't occurred to me. I'd sort of assumed that was the case for everything after the last non-zero word, but wasn't smart enough to think the same would occur for the words before. Smile

Cool beans about the decoder for the DM42! Let me know if you want a hand, either work or testing. I don't have a tremendous number of free cycles right now, but that'd be something I'd be happy to try to make time for.

Thanks!
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