riscv-xbitmanip

This is a discussion group for the Xbitmanip extension for RISC-V. The goal is to create a draft for a bitmanipulation ISA extension, and implement this draft in multiple cores and add compiler support, and then donate this draft to the RISC-V Foundation as a starting point for a new task group for a standard bit manipulation extension. The draft we are working on is based on the work of the original bit manipulation task group that was dissolved in November 2017. Feel free to join the discussion.