DeluxePaint/DPaint original 1986 amiga source code; Includes manual book and reference card pdfs for DPaint 1
PRISM.C is where you can find main()
This source code has been released in 2015, and I've just made a complete package here on Github.
I'm not allowed to pre-compile the software for you, as I'm not licensed to distribute the Software. They never said anything about not distributing the source code however, not to mention that at the time of creating this repo the original website wasn't available, so I wanted to make sure the source was saved.
Also note that the LICENSE file doesn't contain a regular GPL or BSD license, but a custom one - you're not allowed to redistribute the compiled software.