* Add positive range generator

* Allow the Counter module to be instantiated with a Scala range

* Use head/last to determine counter width

Co-authored-by: Jack Koenig <jack.koenig3@gmail.com>

* Let counter overflow naturally when appropriate

We only need to explicitly wrap counters that don't start at zero, or end on a power of two. Otherwise we just let the counter overflow naturally to avoid wasting an extra mux.

* Require counter range to be non-empty

Co-authored-by: Jack Koenig <jack.koenig3@gmail.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Added prefixing and a compiler plugin to improve naming. Only works for Scala 2.12 and above.

Co-authored-by: Jack Koenig <koenig@sifive.com>

The instructions for building Chisel locally didn't include anything about firrtl or treadle.

The steps are:

1. publishLocal current working copy of FIRRTL
2. publishLocal current working copy of Treadle
3. sbt test in chisel3

Treadle tester phase requires new to fix problems found
when running tests in parallel.

* Add `check(...)` affordance

* Add assert (renamed from check and fixed)

* Add verification statements

* Move formal to experimental.verification

* Make test use ChiselStage

`generateFirrtl` has been cut from Chisel

* Fix newly introduced style warnings

* Fix some old style warnings for good measure

* Revert "Fix some old style warnings for good measure"

This reverts commit 31d51726c2faa4c277230104bd469ff7ffefc890.

* Cut scalastyle comments

* Cut formal delimiter comments

Remove scalastyle configurations

* Drop plugin
* Drop scalastyle tests from make recipes
* Remove checkstyle from CI

Change CI to build Treadle master from source. This fixes a bug where
Treadle would be pulled from the latest snapshot (which would pull the
latest FIRRTL snapshot). For bleeding edge PRs that rely on new FIRRTL
features, using a FIRRTL snapshot may result in compilation failures.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

* fix treadle dependency for mill

* bug fix for test

This adds a mechanism for the unittests to be run with the TreadleBac…

This mechanism is not enabled and should not change the behavior of existing tests
A following PR will deliver a switch that will allow changing the backend.
The reasons for this PR
- Treadle tests run much faster, enabling quicker debugging and CI cycles
- This will help ensure fidelity of Treadle to the Verilator backend

A few tests are marked as verilator only due to black box limitations

Change treadle to a direct dependency

I tried to make it a test only dependency but the TesterDriver sits in src/main requiring that
regular compile have access to treadle

Oops, made treadle the default

A number of changes in response to @ducky64 review
- made backend check clearer and add error handling for multiple backends specified
- Fixed duplicate TargetDirAnnotation uses in Treadle backend
- Cleaned up BlackBox test formatting
- Undid unnecessary debugging changes from Counter
- Undid .gitignore change, that should be on another PR

A number of changes in response to @ducky64 review
- Undid debugging changes made to BitWiseOps

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Fix a bug in FlattenSpec where ChiselStage was running the FIRRTL
compiler in ChiselStage and then re-running the FIRRTL compiler. This
changes it to be like InlineSpec and to not run FIRRTL during
ChiselStage.

This was manually backported to 3.3.x.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Remove Deprecated Usages of chisel3.Driver, CircuitForm

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Co-authored-by: Chick Markley <chick@qrhino.com>
Co-authored-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>
Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

This migrates the tests to Chisel 3.4/FIRRTL 1.4. This primarily
involves removing usages of deprecated methods including:

- Remove usages of Driver
- Use ChiselStage methods instead of BackendCompilationUtilities
  methods
- Use Dependency API for custom transforms
- Use extractCause to unpack StackError

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Adds a new method, chiselTests.Util.containsCause, that will search
for a polymorphic exception anywhere in a stack trace. This is useful
if exceptions may move around (e.g., if they are suddenly wrapped in a
StageError).

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Co-authored-by: Albert Magyar <albert.magyar@gmail.com>

* Canonicalize construction of empty Decoupled

* Change signature after dev meeting discussion
* Make EmptyBundle private and final

* Add test case for Decoupled with no payload

* Apply suggestions from code review

Co-authored-by: Richard Lin <richard.lin@berkeley.edu>

Co-authored-by: Albert Magyar <albert.magyar@gmail.com>
Co-authored-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>
Co-authored-by: Adam Izraelevitz <azidar@gmail.com>
Co-authored-by: Richard Lin <richard.lin@berkeley.edu>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

* Closes #1385

Co-authored-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

Move LFSR16 to Compatibility Mode (Deprecated in 3.2)

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>