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contributing: clarify some things

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Emil J. Tywoniak 2025-12-05 12:16:14 +01:00
parent 518610bbc4
commit 16a420afee
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docs/source/yosys_internals/extending_yosys/contributing.rst
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@ -184,10 +184,14 @@ that's not written to be read, just written to run. We improve this bit
by bit when opportunities arise, but it is what it is. by bit when opportunities arise, but it is what it is.
New additions are expected to be a lot cleaner. New additions are expected to be a lot cleaner.
Your change should contain exactly what it needs. This means: The purpose and behavior of the code changed should be described clearly.
Your change should contain exactly what it needs to match that description.
This means:
* nothing more than that - no dead code etc * nothing more than that - no dead code, no undocumented features
* nothing missing * nothing missing - if something is partially built, that's fine,
but you have to make that clear. For example, some passes
only support some types of cells
Here are some software engineering approaches that help: Here are some software engineering approaches that help:
@ -251,7 +255,8 @@ It's often best to use equivalence checking with ``equiv_opt -assert``
or similar to prove that the changes done to the design by a modified pass or similar to prove that the changes done to the design by a modified pass
preserve equivalence. But some code isn't meant to preserve equivalence. preserve equivalence. But some code isn't meant to preserve equivalence.
Sometimes proving equivalence takes an impractically long time for larger Sometimes proving equivalence takes an impractically long time for larger
inputs. inputs. Also beware, the ``equiv_`` passes are a bit quirky and might even
have incorrect results in unusual situations.
.. Changes to core parts of Yosys or passes that are included in synthesis flows .. Changes to core parts of Yosys or passes that are included in synthesis flows
.. can change runtime and memory usage - for the better or for worse. This strongly .. can change runtime and memory usage - for the better or for worse. This strongly
@ -270,7 +275,8 @@ for implicit type casts, always use ``GetSize(foobar)`` instead of
``foobar.size()``. (``GetSize()`` is defined in :file:`kernel/yosys.h`) ``foobar.size()``. (``GetSize()`` is defined in :file:`kernel/yosys.h`)
For auto formatting code, a :file:`.clang-format` file is present top-level. For auto formatting code, a :file:`.clang-format` file is present top-level.
Yosys code is using tabs for indentation. A continuation of a statement Yosys code is using tabs for indentation. A tab is 8 characters wide,
but prefer not relying on it. A continuation of a statement
in the following line is indented by two additional tabs. Lines are in the following line is indented by two additional tabs. Lines are
as long as you want them to be. A good rule of thumb is to break lines as long as you want them to be. A good rule of thumb is to break lines
at about column 150. Opening braces can be put on the same or next line at about column 150. Opening braces can be put on the same or next line