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GPL on the Geneve


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The GPL mode is a mode of the Gate Array on the Geneve Board which causes a rearrangement of the memory layout so that it becomes compatible to a 99/4A console. Apart from that, GPL is a loader for GK-saved cartridges and it contains the GROM contents of GROM 0-2.


GROMs are emulated inside the Gate Array with a selectable speed (to be precise, you can turn on additional wait states).

Edited by mizapf
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To add to the thread...


"GPL" usually consists of 5 files.


The first file, GPL, is an MDOS/Geneve OS program. It sets up the environment, performs the powerups, loads an initial cartridge (optional), and does some basic housekeeping. Of most importance is that it patches the TI ROM, most notably the keyboard and joystick routines. Otherwise, the ROM and GROMs are pretty much identical to those found in a console.


The other four files GPM,GPN,GPO, and GPP are the TI GROMs and ROM files. GPL keeps these "pristine" so that each time you reset the TI mode, you get a fresh copy. This is important because the Geneve places the ROM in a page of RAM, which means the ROM can be corrupted more easily by a crash, and no one likes a corrupt ROM. ;)


This set of program files should probably be called something other than "GPL" as it isn't an interpreter. It is a means to mimic the entire TI operating system, ROM and GROM, as closely to an original TI as possible.

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Did ever there exist any programs that ran from within the TI environment on the Geneve, that then manipulated the cartridge space, Grom or Rom? Since it is still RAM, it seems it should be possible.



It was/is usually easier to write native OS programs where you can request memory pages, use system XOPs (OS calls), and take full advantage of the simpler file IO than it is to try to manipulate TI programs as you describe. That said, the Geneve provides for 'supercart' like abilities, so not only can you load GROM carts, you can run programs that require 8K RAM in the cartridge space.


My S&T BBS software runs from GPL mode. However, the Geneve assembly support does some internal gymnastics which allow it to use the system calls as if it were a native OS program. Manipulating GROM and ROM space is part of the equation. Heatwave BBS is proof of its successful operation. ;)

Edited by InsaneMultitasker
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