Hi, I discovered a few mistakes in my opcode list and have made an update. Main difference is how the unconditional jump instruction is used. Thanks! Michael

Microprocessor Engineering (MPE) provides a modern Forth for the RTX2000 CPU's. They graciously provide a link to a legacy cross compiler, officially "MPE Forth Cross Compiler v5.1 for RTX2000/1/10". Here is a link to the zip file:

https://vfxforth.com/downloads/VfxCommunity/xrtx.zip

The documentation of the cross compiler is excellent, see the PDF in the Manual directory. Included in the manual is a convenient list of opcodes. I have taken a few screenshots of the opcode information, and share it here.

The legacy cross compiler has some challenges regards implementation. An installation key for the software is required, which was graciously provided by MPE upon request. The software has a windows installer, but the software itself runs in a DOS enviroment. I installed the software on a Windows 95 machine, and drop down to DOS in a window to run.

The software has an integrated development environment of sorts, based upon a DOS shell called Xs3. The shell is invoked from different directories, with each directory containing a separate configuration file for the current shell, depending upon the intended activity. The software can cross compile to create either a Tether Forth, ROM forth or RAM forth. The manual is excellent. I'm experimenting with the cross compiler presently.

Here are a few miscellaneous points...

Attached is a screenshot of the MPE Forth Cross Compiler in action on a Windows 95 computer. The software seems OK with simply operating inside a MS-DOS window prompt. Notice the extensive menu.

The memory for the RTX is paged. Each page is 64 KB (32K Words). Special opcode invocations are required to work across page boundaries. I decided to avoid that issue by changing the memory layout on my development board. The board was rewired to provide a contiguous 16K of ROM words, and 16K of RAM words. My board is starting to get pretty messy, and I need to do another spin. See photo.

Finally, something simple. For months I was trying to use the large RTX Programmers Manual in PDF format. I finally had the PDF printed and bound. What a difference in convenience!