Yeah I looked at it, my firmware mostly just aims at bringing up enough stuff to be able to boot ARM, which is essentially just:
- Setting up exception vectors and enabling exceptions
- Reclocking VPU from PLLC
- UART initialization
- SDRAM initialization
- Copying an ARM blinker stub to 0x0
- ARM power domain initialization
- PLLB initialization
- Enabling passthrough mapping for ARM
- ARM AXI interface initilaization
I'm still trying to figure out what I'm missing in order to get it to work but I suspect it's related to not properly setting up the ARM PLL. I was going to port the RPi clock management driver from Linux but I don't have the time at the moment.
As far as the compiler goes, I think it works reasonably well, though I only tested it by compiling my own code with it, there may be things that cause it to error out (anything that involves the frame pointer like VLAs/some C++ features). Also code quality is not ideal since it still doesn't make use of conditional instructions (aside from conditional branches) and doesn't implement AnalyzeBranch to eliminate redundant branches.
I started cleaning up TableGen to turn multi-instruction asm prints into glue DAG in SelDAGtoDAG but I still have to do it for like 4 instructions, which is pretty much a requirement to have MC code emission.