Daniel, just in case you didn't see the email from the bug report, I ended up writing a LFSR implementation at the same time you did: http://bugs.libre-riscv.org/show_bug.cgi?id=71#c4 https://git.libre-riscv.org/?p=soc.git;a=blob;f=TLB/src/LFSR2.py;h=8cdb2cc560ca9a28e88d7e96e81213da2c44bf3d;hb=HEAD