What software, driver, firmware, and OS?

I just want to develop to test a functional IC. I don't need any "drivers" or anything more than simple assembler/machine instructions implemented on the microarchitecture to test electrical circuitry and pathways, buses, units, the stack, registers, etc.

I am not going to develop an "OS" for this, although it would be ideal. And assuming a memory map, I would expect direct memory access to be intercepted by devices within the same board(i.e., no "device driver" is really needed for such a trivial test, and are more accustomed to user-level environments, application software, and/or a kernel).

And yes, it is just to know how, as it's vital to programming, and will assure more accuracy and completeness in all related studies of computers.

We can easily implement a pong game using a simple 8-bit micrprocessor, some video mapped memory and a simple card, display device and simple video output connective interface, and some main memory. Maybe I went a bit too far thinking of a PCI IC video device. I'd rather just implement an 8-bit micrprocessor with dedicated on-die components, 16-bit address bus, 8 registers, a stack concept, simple microarchitecture, etc. Then I could develop a PCB for it, add main memory, and see what happens there. If only there were access to the right quality spinach for less money I'd be closer to my goals and desires.

PS: CPUs usually come with microcode specifications, and ROM. That would be insane to get done by one person with almost no money virtually or income, connections or tools, but worth it just to say I did it.

Thanks for the link, Jabber!