Missing documentation for NOOP_HOME environment variable

[zlh20040308]

When following the README to build NutShell and generate Verilog
(using make), the build fails with:

java.util.NoSuchElementException: NOOP_HOME

unless the environment variable NOOP_HOME is defined.

However, I couldn’t find any mention of NOOP_HOME in the README or
the build documentation. This makes the initial setup a bit confusing
for new users, since the failure happens during elaboration without
prior notice.

[fly-1011]

There is an env.sh file in the NutShell directory; using source env.sh should resolve this issue.

[zlh20040308]

Thanks for the clarification.

I see that env.sh sets NOOP_HOME, but I couldn't find any mention of
sourcing this script in the README or build instructions. Since the
build fails without it, it might be helpful to document this step
explicitly for new users.

Just wanted to point this out from a documentation perspective.