Well,

The problem with gfa (and many languages) is that the instructions used (e.g. prcircle) when compiled are translated into assembly language tailor made for just one computer model. Diverge the hardware just a little and you're left with an incompatible binary.

Now, as you know, the jaguar has vastly different achitrecture than the ST. So much in fact that pretty much only the 68000 is common to the 2 machines. Memory mappings, O/S calls, etc etc are totally different.

So, unless you get someone to make the compiler to covert your source code to stuff that the jag will comprehend, you're b0rked.

Quick example to make my point: trap 14 function 2 gives you the physbase on st. What does it do on the jaguar? Are traps set up? Do they have the same parameter passing scheme as TOS?