tcamp@ecsvax.UUCP (10/30/87)
A few weeks ago I posted a query on the net concerning (a) availa- bility of public-domain or shareware software to run under GEM on PC-compatibles, and (b) inexpensive sources for the GEM developers' kit. I received several responses, included some from folks at DRI, which indicated (a) there is no known p.d. or shareware for GEM on the PCs, and (b) that the only hope in a reduced-priced developers' kit is a special Amstrad version which does not include a license to distribute the GEMVDI. I was interested to read in Balma and Fittler, <Programmer's Guide to GEM> that if the GEM bindings are known, programs in many languages can access GEM functions. So I'm inclined to wonder if we can figure out enough about GEM to write some of our own bindings and write some programs using our own C compilers. In fact, Balma and Fittler (pp. 438-446) list the bindings for GEM under the PC, although no explanations are given. I would presume (a) that GEM utilizes one interrupt (is it 0x09f?) on the analogy of the operating system, and (b) the function codes listed on pp. 438-439 of Balma and Fittler are passed in one register for each call to the GEMVDI interrupt, with data structure pointers (offsets and segments) in other registers, appropriate to the particular function code. Can anyone add to this? Since Mark Williams and others have released GEM bindings for their compilers for the Atari ST, I'd presume that there would be no legal problems in our developing our own bindings to use for GEM programming, unless Mark Williams and others have had to pay DRI for the right to use their function names, etc. I'd be quite interested if folks on the net can supply further information. -- Ted A. Campbell | Duke Divinity School | Durham, NC 27706 | email: tcamp@ecsvax |