Attached at the bottom of this page is a summary of available open
source CPUs. For comparison, the NIOS commercial CPU is also included.
An even longer list obtained from
In my (Wesley's) opinion, there are really only four candidates:
The other options can quickly be eliminated based on one of:
For a ball-park comparison of their sizes with features toggled off (x
depends on the FPGA):
I would further eliminate the openrisc as it has comparable complexity
to the LEON3, but is less mature.
Both LEON3 and latticemico32 are heavily tested and deployed in
Summary of experience working with the "big three":
The LEON3 comes as part of a IP core library called grlib. grlib is
based around the AMBA bus and includes several useful peripherals that
can be attached:
The development environment is very easy to work with:
I have not yet moved beyond synthesizing it for complexity/speed