How long did it take you to do this? Did you have previous experience with all the various aspects (compiler, FPGA, instruction set etc) before or did you build it up as you went along?

I am an autodidact for all these things (FPGA, compiler). This is my first FPGA-Verilog project and my first compiler project. I have learned these things specifically for this project. It took me 2 years to complete this project, during evenigs and week-ends. I have not counted exactly, but probably between 200 and 400 hours of work.