I've been putting distance between myself and GCC for now. Mainly because I'm not sure how useful it would be at this point. Also because I want to make some solid progress to keep myself motivated. GCC will produce inefficient code to start with, and will require many optimization rounds. I need to become more familiar with TMS9900 assembly in order to do that optimization. I would also like to get a working foundation going sooner, even if its written in assembly.
I've been spending a lot of time at work lately spelunking through code, and I'm not too excited to do some more when I get home. Besides, there is a lot of stuff to get working that I can use the assembler for. Also I need to exercise GAS some to confirm that it works well enough to trust it fully. I think it should be fine, but you never know...
There is now a tool ELF2CART which will extract the .text section from a TI ELF file. This is handy for stripping the ELF headers and unneeded sections for use in a TI cart. Seems to work fine.
At this point, I need to get TI init code working, confirm that the jump instructions work, and get some basic output on the screen.