diff options
Diffstat (limited to 'doc/GHDL_implementation_of_VHDL.rst')
| -rw-r--r-- | doc/GHDL_implementation_of_VHDL.rst | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/doc/GHDL_implementation_of_VHDL.rst b/doc/GHDL_implementation_of_VHDL.rst index 808c39140..5df2ec5d1 100644 --- a/doc/GHDL_implementation_of_VHDL.rst +++ b/doc/GHDL_implementation_of_VHDL.rst @@ -29,6 +29,8 @@ VHDL standards .. index:: v02 +.. index:: v08 + This is very unfortunate, but there are many versions of the VHDL language, and they aren't backward compatible. @@ -64,6 +66,9 @@ Minors corrections were added by the 2002 revision of the VHDL standard. This revision is not fully backward compatible with VHDL-00 since, for example, the value of the `'instance_name` attribute has slightly changed. +The latest version is 2008. Many features have been added, and GHDL +doesn't implement all of them. + You can select the VHDL standard expected by GHDL with the :samp:`--std=VER` option, where :samp:`VER` is one of the left column of the table below: @@ -94,8 +99,9 @@ table below: 08 Select VHDL-2008 standard (partially implemented). -You cannot mix VHDL-87 and VHDL-93 units. A design hierarchy must have been -completely analyzed using either the 87 or the 93 version of the VHDL standard. +The 93, 93c, 00 and 02 standards are considered as compatible: you can +elaborate a design mixing these standards. However, 87, 93 and 08 are +not compatible. .. _psl_implementation: @@ -173,8 +179,8 @@ changed with the :option:`--work=NAME` option of GHDL. To keep the list of design units in a design library, GHDL creates library files. The name of these files is :file:`NAME-objVER.cf`, where -`NAME` is the name of the library, and `VER` the VHDL version (87 -or 93) used to analyze the design units. +`NAME` is the name of the library, and `VER` the VHDL version (87, +93 or 08) used to analyze the design units. You don't have to know how to read a library file. You can display it using the *-d* of `ghdl`. The file contains the name of the |