Hey guys,
Figured some folks might find this helpful. SnickerOS is a baremetal OS I'm building from the ground-up as a learning project.
Among other things, it has my debugging toolchain and some simple baremetal code working without stdlib builtins. If anyone wants to use it as a springboard for their own baremetal projects or w/e, be my guest. That's why I'm posting it.
Link is: https://github.com/hedgeberg/SnickerOS
Again, functionality is limited but it is a working build environment with very minimal xilinx code; the only xilinx code I've relied on to date is the ps7_init code which trains the RAM delays, since those are so complex. Other than that, this has been implemented by hand. I hope someone finds it useful!
--hedge