I fiexed my earlier problem....thought it was identical code, but turns out it wasn't, a literal number was being used twice....only had to comment out the program about 90% to find that!
Anyhow, Once using read-only uav's instead of the constant buffer, I fully expected things to work...well, they dont. I'm pulling from a network data stream, and byte reversing for an LSB system like Caymans, only when I enabled my debug output on Tahiti, I'm seeing all my stuff reversed again...at first I thought I was just dyslexic, (I mean, I know ASM dst,src stuff exacerbates my dyslexic tendencies...) so I pulled up as bytes the ram I'm passing up, and the debug readback of the data, and sure enough, its reversed. 0x00000001 became 0x01000000.
In fact, upon further checking, it seems all my bfi masks are reversed, and just about all positions are reversed...Looks to me like is MSB, but I did want to check and confirm just to make sure I'm not more dyslexic than I thought, and/or not as crazy as I thought!