John, That would be ideal, but beyond my capabilities at the moment. Swapping in and out of the optRom is still a mystery to me. I don't have the book you are referring too but I have looked through the code that was created by you and Steve after working on it. At this point I'm just trying to return back to BASIC after populating the ALT LCD with the code.
Kurt On Tue, Sep 10, 2019, at 10:18 AM, John R. Hogerhuis wrote: > Why not just put all the LINE code into your optrom and run it from there? > You can do a far call to the opt ROM. Maybe that's what you're doing. Just > don't see why altlcd is in involved. > > The procedure for a far call and return is a trick but it is covered in > Secrets of the ROM book by Mo Budlong. You don't have that? I can write a > wiki page based on it. > > Presumably you should be able to sneak the far call and return into your > basic program as a special string or as a hidden high numbered line. > > -- John. > > > On Tue, Sep 10, 2019, 6:37 AM Kurt McCullum <ku...@fastmail.com> wrote: >> __ >> I've got a question for those who have dabbled with OptROM code. >> >> Question: What is the proper way to exit out of the OptROM and back to BASIC. >> >> Reason: The NEC 8201a doesn't have the LINE function build into the system >> ROM. There is a RAM version of the utility. I managed to relocate the code >> so that it runs in the ALT LCD section of memory. But to prevent having to >> load the LINE code from a TPDD device, I put code into some of the empty >> space I have in the SARDOS ROM to load that code. I call it similar to how >> the cold start recovery routine of TS-DOS is called. I poke a value and then >> check for it when EXEC 62394 is called. That works, and I am able to load >> the code into ALT LCD, but I can't seem to get out of the OptROM cleanly. If >> I try RET then it ends up in an infinite loop. If I do a RST 1, similar to >> how the TS-DOS recovery code does, it loads properly but kicks an SN error >> in BASIC. >> >> Hope somebody can shed some light on this because I've got about 11k of >> space in the SARDOS ROM that I would like to put some of the NEC utilities >> in. >> >> Kurt
