Assembler
(Built in 6309/GimmeCPU assembler)

The GPU Assembler  and  6309 Assembler enhancements must be loaded via update prompt into User EEPROM and requires 96K of the 128K available there otherwise only a very basic 6309 assembler built into the 256K system ROM will be available.

Testing 6x09 assembly language programs becomes much easier. The basic program starts from the X prompt and requires one full monitor, however the second monitor  may be split into multiple virtual screens and run anything else and any one of these may be used as a test window for the assembler by running AHOST.BIN from BASIC on the virtual CoCo that owns that  virtual screen.
This program has all the features of DISK EDTASM plus a better VI like editor and in addition to 6809 code can help you create programs in 6309 code and Gx32  (Gx32 is the language of the GIMMEx32 GPU) code.

The GPU will have up to 256 Instructions with 56 reserved for the Math Co-processor component.

That leaves 200 commands for other things such as:
As for the CPU part of the assembler that would fully support the 6309 and the Turb09.

The "Assembler enhancements" package includes a full screen editor that can work in 80/132 x 60 column mode and saves to :u0 no matter how you have u0: formatted.