HP-41 instruction print bug found

[hth]

(11-05-2019 03:36 PM)mfleming Wrote:  

(11-05-2019 01:56 AM)hth Wrote:  That is a good idea in theory, but I do not think it will work. The problem I think is that the disable switch actually relocates the printer ROM from page 6 to page 4. Since there are page 4 modules, it will probably create page 4 conflicts.

Tested, and works. The Mass Storage ROM shows up in 7, LIB#4 remains in 4, and the ROM plugged into page 6 (HEPAX) shows up in a CAT 1G and works fine. You'll have to test relocating a modified copy of the printer rom in RAM to page 6

Interesting. Did you test by executing any code in LIB4 that access the LCD? In that case it should go out and re-run the instruction on the bus.

If that works, then it may be possible to replace both the HP-IL ROMs in place, but just running alternative modules on top of it? It may be that having YFNZ in page 7 causes problems with a printer in page 6 is that the printer makes call into page 7 assuming the IL ROM page is there.