From: usotsuki@buric.co   
      
   On Tue, 23 Jan 2024, I am Rob wrote:   
      
   >> Several years ago I was dinking with a Laser 128, and later with the   
   >> SimSystem IIe emulator which had a similar - it seems, string-hacked -   
   >> firmware. I got to thinking about the occasional programs I'd try with   
   >> the 128 or SimSystem IIe that would blow up.   
   >   
   > I think you meant "tinkering", "dinking" is such a harsh word.  :)   
      
   I tend to be very dysphemistic when I talk about myself.   
      
   >> Sometimes, these were old file-cracked single-load games, which I was able   
   >> to get to work by using the old System Master to load an Apple ][ ROM, and   
   >> then run them. That didn't always work.   
   >   
   > I don't think it is the ROM that is at fault.  More likely the use of   
   > illegal opcodes which the IIe tries to execute.   
      
   If it worked on a 65SC02-based //e, then it most likely wasn't an ILLOP   
   problem.   
      
   An example of a game that works on the Laser 128 if run from 50-sector   
   INTBASIC is Cu-bit.   
      
   > Maybe I can save you some trouble.  The biggest reason it cannot work   
   > (Laser ROM in a IIe/IIc) is the firmware calls.  The Laser has a third   
   > layer of firmware.  From what I can tell, it engages a softswitch that   
   > switches in a 2nd layer of firmware under the $C100.C7FF range apart   
   > from the regular firmware.  This won't work on a IIe/IIc.   
      
   The //c does the same thing in a different way for the same reason (32K   
   firmware in 16K of space).   
      
   > For the most part, the IIe/IIc ROM's should work in a Laser 128.   
   >   
   >> That said - it's a matter of implementation, of course: it would need to   
   >> be tweaked to get around those hardware (ROM-banking) differences. And   
   >> I'm not really sure what-all those differences actually are.   
   >   
   > It has been awhile so I am trying to remember off the top of my head.   
   > But what the Laser does is to one of the listings, either monitor   
   > listing or applesoft listing, was to look up the keywords from the $C300   
   > or $C800 firmware.  This won't work on a IIe/IIc.   
      
   Prolly the monitor, though iirc pieces of BASIC are located in the Cx   
   space too.   
      
   > But  I don't see why a IIe ROM won't work in a Laser 128.   
      
   The "ROM 255" //c may have a better chance of working since it doesn't   
   need to bank; there's just 16K ROM, full stop, rather than the 32K of   
   other models.   
      
   I know the //e has the diagnostic code at C600.   
      
   > > I'd try to do even more if I were sure it wouldn't break other stuff (such   
   >> as the ProDOS-8 clone check)...   
   >   
   > I believe there is a program on the Franklin boot disk that shows how to   
   > defeat the Prodos clone check.   
      
   Workarounds are known.   
      
      
      
   > Disassembling the Laser ROM did give me some insight to as why they were   
   > not subject to Apple's lawsuits, though.  I recommend disassembling it   
   > for the curiousity, if not anything else.   
      
   It's definitely different code.   
      
   -uso.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)