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J-F Garnier · (This post was last modified: 03-09-2017 08:07 AM by J-F Garnier.)

(03-08-2017 11:12 PM)rprosperi Wrote: Quite a non-intuitive rom-mapping scheme. Seems like there are 4 sets of 4 rom banks, though they appear to be loaded/assigned in some unexpected order. I will check further with a real 75C. Why does EMU75 allocate ROMs in different order than a real 75, does'n that mean you had to re-write a lot of code to do the ROM mgmt?

The ROM-enable slot numbers vs the physical ports is a bit strange (non-consecutive slots), the PODPMS1C LEX translates the roma-romp identifiers to the slots.
In my emu75 test version, I used a simpler slot scheme, it doesn't hurt anything, but makes the PODPMS1C translation ineffective. This may change in final emu75 version.

Quote:Also, it appears that the PMSCMDS and PODPMS1C LEX files cannot be resident at the same time in EMU75. I installed the latter (with the former already loaded), and upon restart of EMU75, I get an "ERROR" display and the LCD display output is disabled. It took a few moments to realize the LEX files conflict, but upon PURGEing PMSCMDS, EMU75 normal behavior was restored. Is this an EMU75 issue or does the conflict also exist in real h/w (I don't have a PMS yet)? I'd guess that when Bob Bradley (or whoever) hacked the original LEX, perhaps he didn't change the LEX ID.

Having 2 LEXs with same LEX numbers will for sure confuse the HP75 OS. Don't do that!

Quote:So, on a real 75, it appears the ROM banks are be allocated like this:

PMS:
4 x 8KB RAM/ROMs, :roma, - :romd

Port1:
4 x 8KB ROMs, :rome - :romh

Port2:
4 x 8KB ROMs, :romi - :roml

Port3L
4 x 8KB ROMs, :romm - :romp

Will update this after checking out a 75 in a POD (which plugs-in to Port3).

Anyone - Please correct the above if you know more/better

On the real HP75, the roma-romd identifiers of PODPMS1C select the internal ROM slots (altrom, melrom)
This is only true for PODPMS1C, this is the one big part of the patch. In the regular PMSCMDS LEX, the roma-roml select the PMS RAM banks only (so only roma-romb for one real PMS in any port).

For more details, you can refer on the HP75 group to the documents:
- Faline source code: source code of the PMSCMDS LEX,
- ROM_mapping_search Documents the ROM slot addresses, and the search orders for the system (to be read at least 3 times to fully understand it :-),
- and of course the PMS manual.

J-F