We added bitlash as Xilinx SDK many month ago, is also fully integrated now. There is some weird thing about the library add order to make the bsp to compile, but when done right all compile out of box.
YES! the simple RGB LED prepared for 31C3 was done with Arduino code, had to fix a problem on digitalWrite, then it worked. So far I only tested digitalWrite on MIO7, and MIO7 is enabled as output in bootrom, that masked the issue in the library (the code changed the pin to output, but did not enable it)
only an hour or two and the Arduino Firmata firmware did compile and work also, pretty cool, connecting reads made firmate client app, and it will control the Zynq MIO pins from the GUI. OK there are some more hours needed to get it fully working, but even the first test was useful for base level testing
Once upon a time I got a Virtex-7 based board from oven and had to test it. For some silly reason I did not wanted to make counter for LED toggle, so I wrote some code.. and then did take the Arduino "LED Blinky" code.
Compiled it, loaded the bit file into Virtex7, and yeah the LED did blink!
This was the first time I did Arduino Code on FPGA, and this first code was used to test the most expensive FPGA board I have designed.
The first version was targeting Microblaze MCS as I did think that Microblaze does cost money, but hey Microblaze FULL (not MCS) is free, and is free with free tools. Isnt that cool?
Of course the Cortex-A9 cores on ZYNQ can also be used using completely free tools.