Been a while, thought I should just give a heads up. I have the emulator and LLVM assembler working now with nearly all the instructions, including branch and memory access. The debugger now supports stepping and breakpoints for supervisor-level code (think kernel/firmware)...need to add support now for user-level code (applications), then I can hook up the rendering and keyboard interrupts again (broken since the change from my hacky assembler days to LLVM)
I have also been making progress with the FPGA. I worked over the weekend to get a simple Mode0 HDMI output working. I can now at least fill the screen with the letter 'A'! I know, sounds like not much, but for me it's a milestone. I now need to get the Block RAM VRAM working, issues with clock timing I need to work out...then I can output text on the HDMI screen attached to the FPGA. Next step will be to start coding the ALU for the CPU.