Add more documentation

Signed-off-by: Clifford Wolf <clifford@clifford.at>

docs/source/index.rst

@@ -21,5 +21,7 @@ at the moment.)
 
    quickstart.rst
    reference.rst
+   verilog.rst
+   verific.rst
    license.rst
 

docs/source/verific.rst

@@ -0,0 +1,130 @@
+
+SystemVerilog, VHDL, SVA
+========================
+
+TBD
+
+``verific -sv <files>``
+
+``verific -vhdl <files>``
+
+``verific -import <top>``
+
+TBD
+
+Supported SVA Property Syntax
+-----------------------------
+
+SVA support in Yosys' Verific bindings is currently in development. At the time
+of writing, the following subset of SVA property syntax is supported in
+concurrent assertions, assumptions, and cover statements when using the
+``verific`` command in Yosys to read the design.
+
+High-Level Convenience Features
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Most of the high-level convenience features of the SVA language are supported,
+such as
+
+  * ``default clocking`` ... ``endclocking``
+  * ``default disable iff`` ... ``;``
+  * ``property`` ... ``endproperty``
+  * ``sequence`` ... ``endsequence``
+  * Parameters to sequences and properties
+  * Storing sequences and properties in packages
+
+In addition the SVA-specific fetures, the SystemVerilog ``bind`` statement and
+deep hierarchical references are supported, simplifying the integration of
+formal properties with the design under test.
+
+The ``verific`` command also allows parsing of VHDL designs and supports binding
+SystemVerilog modules to VHDL entities and deep hierarchical references from a
+SystemVerilog formal test-bench into a VHDL design under test.
+
+Expressions in Sequences
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Any standard Verilog boolean expression is supported, as well as the SystemVerilog
+functions ``$past``, ``$stable``, ``$rose``, and ``$fell``. This functions can
+also be used outside of SVA sequences.
+
+Additionally the ``<sequence>.triggered`` syntax for checking if the end of
+any given sequence matches the current cycle is supported everywhere in expressions
+used in SVA sequences.
+
+Sequences
+~~~~~~~~~
+
+The following sequence operators are currently supported. Note that some of
+them only allow expressions in places where complete SVA would allow sequences
+as well.
+
+Most importantly, expressions and variable-length concatenation are supported:
+
+  * *expression*
+  * *sequence* ``##N`` *sequence*
+  * *sequence* ``##[*]`` *sequence*
+  * *sequence* ``##[+]`` *sequence*
+  * *sequence* ``##[N:M]`` *sequence*
+  * *sequence* ``##[N:$]`` *sequence*
+
+Also variable-length repetition:
+
+  * *expression* ``[*]``
+  * *expression* ``[+]``
+  * *expression* ``[*N]``
+  * *expression* ``[*N:M]``
+  * *expression* ``[*N:$]``
+
+And some additional more complex operators:
+
+  * *sequence* ``or`` *sequence*
+  * *sequence* ``and`` *sequence*
+  * *expression* ``throughout`` *sequence*
+
+The following operators are currently **unsupported** but support for them is
+planned for the near future:
+
+  * ``first_match(`` *sequence* ``)``
+  * *sequence* ``intersect`` *sequence*
+  * *sequence* ``within`` *sequence*
+  * *expression* [=N]
+  * *expression* [=N:M]
+  * *expression* [->N]
+  * *expression* [->N:M]
+
+Properties
+~~~~~~~~~~
+
+Currently only a certain set of patterns are supported for SVA properties:
+
+  * [*antecedent_condition*] *sequence*
+  * [*antecedent_condition*] ``not`` *sequence*
+  * *antecedent_condition* *sequence* *until_condition*
+  * *antecedent_condition* ``not`` *sequence* *until_condition*
+
+Where *antecedent_condition* is one of:
+
+  * sequence ``|->``
+  * sequence ``|=>``
+
+And *until_condition* is one of:
+
+  * ``until`` *expression*
+  * ``s_until`` *expression*
+  * ``until_with`` *expression*
+  * ``s_until_with`` *expression*
+
+Clocking and Reset
+~~~~~~~~~~~~~~~~~~
+
+The following cunstructs are supported for clocking in reset in most of the
+places the SystemVerilog standard permits them, but properties spanning
+multiple different clock domains are currently not supported.
+
+  * ``@(posedge`` *clock* ``)``
+  * ``@(negedge`` *clock* ``)``
+  * ``@(posedge`` *clock* ``iff`` *enable* ``)``
+  * ``@(negedge`` *clock* ``iff`` *enable* ``)``
+  * ``disable iff (`` *expression* ``)``
+

docs/source/verilog.rst

@@ -0,0 +1,49 @@
+
+Formal extensions to Verilog
+============================
+
+TBD
+
+``read_verilog -formal``
+
+SystemVerilog Immediate Assertions
+----------------------------------
+
+TBD
+
+``assert(<expr>);``
+
+``assume(<expr>);``
+
+``cover(<expr>);``
+
+SystemVerilog Functions
+-----------------------
+
+TBD
+
+``$past``
+
+``$stable``
+
+``$rose``, ``$fell``
+
+Liveness and Fairness
+---------------------
+
+TBD
+
+``assert(eventually <expr>);``
+
+``assume(eventually <expr>);``
+
+Unconstrained Variables
+-----------------------
+
+TBD
+
+Nonstandard Extensions in Yosys
+-------------------------------
+
+TBD
+