Issue warning messages for missing parameterized modules and attempts to set initial values.
Replace simple "if (cell-type)" with "else if" chain.
Fix FIRRTL shift handling.
Add support for parameterized modules, $shift, $shiftx.
Handle default output file.
Deal with no top module.
Automatically run pmuxtree pass.
Allow EXTRA_FLAGS and SEED parameters to be set in the environment for tests/tools/autotest.mk.
Support FIRRTL regression testing in tests/tools/autotest.sh
Add xfirrtl files to test directories to exclude files from FIRRTL regression tests that are known to fail.
Don't pad logical operands to one bit.
Use operand width and signedness in $reduce_bool.
Shift amounts are unsigned and shouldn't be padded.
Group "is invalid" with the wire declaration, not its use (otherwise it is incorrectly wired to 0).
o Not all derived methods were marked 'override', but it is a great
feature of C++11 that we should make use of.
o While at it: touched header files got a -*- c++ -*- for emacs to
provide support for that language.
o use YS_OVERRIDE for all override keywords (though we should probably
use the plain keyword going forward now that C++11 is established)