diff options
Diffstat (limited to 'doc/using')
| -rw-r--r-- | doc/using/ImplementationOfVHDL.rst | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/doc/using/ImplementationOfVHDL.rst b/doc/using/ImplementationOfVHDL.rst index 331a7e10c..8836d0070 100644 --- a/doc/using/ImplementationOfVHDL.rst +++ b/doc/using/ImplementationOfVHDL.rst @@ -118,10 +118,10 @@ GHDL implements a subset of :wikipedia:`PSL <Property_Specification_Language>`. PSL implementation ------------------ -A PSL statement is considered a process, so it's not allowed within +A PSL statement is considered as a process, so it's not allowed within a process. -All PSL assertions must be clocked (GHDL doesn't support unclocked assertion). +All PSL assertions must be clocked (GHDL doesn't support unclocked assertions). Furthermore only one clock per assertion is allowed. You can either use a default clock like this: @@ -142,6 +142,7 @@ or use a clocked expression (note the use of parentheses): Of course only the simple subset of PSL is allowed. Currently the built-in functions are not implemented, see `issue #662 <https://github.com/ghdl/ghdl/issues/662>`_. +PSL functions `prev()`, `stable()`, `rose()` and `fell()` are supported with GHDL synthesis. PSL usage --------- @@ -195,14 +196,14 @@ PSL in a VHDL(-2008) design without embedding it in comments. ghdl -a --std=08 vhdl_design.vhdl ghdl -e --std=08 vhdl_design -PSL vunit files +PSL vunit files (VHDL-2008 / Synthesis only) ^^^^^^^^^^^^^^^ GHDL supports vunit (Verification Unit) files. .. code-block:: VHDL - vunit vunit_name (design_name) + vunit vunit_name (entity_name(architecture_name)) { default clock is rising_edge(clk); assert always cnt /= 5 abort rst; @@ -218,12 +219,17 @@ GHDL supports vunit (Verification Unit) files. .. HINT:: - The PSL vunit file has to be analyzed/elaborated together with the VHDL design file, for example: + The PSL vunit file has to be analyzed together with the VHDL design file, for example: .. code-block:: bash ghdl -a --std=08 vhdl_design.vhdl vunit.psl - ghdl -e --std=08 vhdl_design + + Or when using the `--synth` command: + + .. code-block:: bash + + ghdl --synth --std=08 vhdl_design.vhdl vunit.psl -e vhdl_design Source representation |