NP-41 Emulator (may be)

[Chris Chung]

(01-26-2016 12:04 AM)rprosperi Wrote:  Yes, the 41C family had 4 physical Ports, each of which could address 2 x 4K "Pages", and said Pages could also be banked up to 4 layers deep. Note that 41C ROM code consists of 10-bit "words" (I may not have the exact terminology correct). Port-1 addressed Pages 8/9, Port-2 - A/B, Port-3 - C/D, and Port-4 - E/F. As you guessed, the Functions in these ROMs were added into the CAT-2 listing.

There are,also some special cases, where devices inserted into physical ports were mapped to different memory Pages, e.g. the Printer was mapped to Page-6, HP-IL Mass Storage to Page-7, and others.

I will email you a copy of Paul Kaarup's Superb "HP-41 Programmers Handbook". It contains a huge amount of useful information all in one place, and may provide insights and reference material as you explore this.

I can also email you a sample ROM image (e.g. for the MATH ROM) if that's what you mean.

Yes, I would like to play w/ a basic / typical ROM.

There are about 20K free flash memory on the "Slim" unit that I can play w/. Will map it w/ the MATH ROM you mentioned and give it a go. If the ROM code are the same byte code as in the 41C system ROM, then I am familiar w/ them and be able to trace the ROM execution to gain more understanding.

I was not sure before and thought that the ROM contains user domain key codes. I understand the 10 bit instruction codes but am lost on the user entered program codes. Hopefully after reading the Programmers Handbook I can gain the needed knowledge. For my current register memory "save" and "load", I just dump and load the memory image after entering the user programs by hand w/o understanding the instructions / data.