diff options
Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 26 |
1 files changed, 14 insertions, 12 deletions
@@ -257,13 +257,9 @@ for them: - Non-synthesizable language features as defined in IEC 62142(E):2005 / IEEE Std. 1364.1(E):2002 -- The ``tri``, ``triand``, ``trior``, ``wand`` and ``wor`` net types +- The ``tri``, ``triand`` and ``trior`` net types -- The ``config`` keyword and library map files - -- The ``disable``, ``primitive`` and ``specify`` statements - -- Latched logic (is synthesized as logic with feedback loops) +- The ``config`` and ``disable`` keywords and library map files Verilog Attributes and non-standard features @@ -370,7 +366,7 @@ Verilog Attributes and non-standard features - When defining a macro with `define, all text between triple double quotes is interpreted as macro body, even if it contains unescaped newlines. The - tipple double quotes are removed from the macro body. For example: + triple double quotes are removed from the macro body. For example: `define MY_MACRO(a, b) """ assign a = 23; @@ -420,9 +416,15 @@ Verilog Attributes and non-standard features expressions as <size>. If the expression is not a simple identifier, it must be put in parentheses. Examples: ``WIDTH'd42``, ``(4+2)'b101010`` -- The system tasks ``$finish`` and ``$display`` are supported in initial blocks - in an unconditional context (only if/case statements on parameters - and constant values). The intended use for this is synthesis-time DRC. +- The system tasks ``$finish``, ``$stop`` and ``$display`` are supported in + initial blocks in an unconditional context (only if/case statements on + expressions over parameters and constant values are allowed). The intended + use for this is synthesis-time DRC. + +- There is limited support for converting specify .. endspecify statements to + special ``$specify2``, ``$specify3``, and ``$specrule`` cells, for use in + blackboxes and whiteboxes. Use ``read_verilog -specify`` to enable this + functionality. (By default specify .. endspecify blocks are ignored.) Non-standard or SystemVerilog features for formal verification @@ -457,7 +459,7 @@ Non-standard or SystemVerilog features for formal verification supported in any clocked block. - The syntax ``@($global_clock)`` can be used to create FFs that have no - explicit clock input ($ff cells). The same can be achieved by using + explicit clock input (``$ff`` cells). The same can be achieved by using ``@(posedge <netname>)`` or ``@(negedge <netname>)`` when ``<netname>`` is marked with the ``(* gclk *)`` Verilog attribute. @@ -470,7 +472,7 @@ from SystemVerilog: - The ``assert`` statement from SystemVerilog is supported in its most basic form. In module context: ``assert property (<expression>);`` and within an - always block: ``assert(<expression>);``. It is transformed to a $assert cell. + always block: ``assert(<expression>);``. It is transformed to an ``$assert`` cell. - The ``assume``, ``restrict``, and ``cover`` statements from SystemVerilog are also supported. The same limitations as with the ``assert`` statement apply. |