(SOLVED) 41CL - DOUBLE HEPAX ACCESS and MMU CONFIG

[rprosperi]

(08-23-2019 05:43 AM)Ángel Martin Wrote:  PS. you're not likely to be familiar with the HEPAX initialization during the CAL_ON event, but it's a piece of SW art. The HEPAX first gets plugged into the lower page of the port where it is physically plugged, and it immediately runs some initialization code. That code establishes the bus parameters, and uses that information to write a code stub in the HEPAX RAM page. That small routine is then executed (!), which thanks to the custom OpCode re-allocates the HEPAX ROM into the smallest page available - and provides XROM id#'s for all the HEPAX RAM pages as well.

Wow, really clever! More evidence of the genius of the HEPAX team, not that more is needed...

So, I have to ask: how can HEPAX create and use a custom OpCode, since the 41's CPU is fixed; i.e. how is the CPU's vocabulary extended?

Back to the READROM/WRTROM topic - why can't these commands be used to simply copy the block(s) that contains the HEPAX File System? It seems to be consistent with the descriptions in both the manual and your comments here, yet the manual suggests to not do so (though it does not say this will cause errors...). Perhaps the statement in the manual is merely pointing out that the file-level commands are available for more granular access than copying entire pages?