User`s manual

Specifying the resource libraries
ModelSim Xilinx User’s Manual Design Libraries 2-33
Alternate IEEE libraries supplied
The installation directory may contain two or more versions of the IEEE library:
• ieeepure
Contains only IEEE approved std_logic_1164 packages (accelerated for
VSIM).
• ieee
Contains precompiled Synopsys and IEEE arithmetic packages for the std_logic
base type, which have been accelerated by Model Technology.
You can select which library to use by changing the mapping in the modelsim.ini
file. The modelsim.ini file in the installation directory defaults to the ieee library.
Regenerating your design libraries
Depending on your current ModelSim version, you may need to regenerate your
design libraries before running a simulation. Check the installation README file
to see if your libraries require an update. You can easily regenerate your design
libraries with -refresh. You must use vcom
(CR-106) with the -refresh option to
update the VHDL design units in a library, and vlog
(CR-141) with the -refresh
option to update Verilog design units. By default, the work library is updated; use
-work <library> to update a different library. For example, if you have a library
named mylib that contains both VHDL and Verilog design units:
vcom -work mylib -refresh
vlog -work mylib -refresh
An important feature of -refresh is that it rebuilds the library image without using
source code. This means that models delivered as compiled libraries without
source code can be rebuilt for a specific release of ModelSim (4.6 and later only).
In general, this works for moving forwards or backwards on a release. Moving
backwards on a release may not work if the models used compiler switches or
directives (Verilog only) that do not exist in the older release.
Note: As in the example above, you will need to use vcom for VHDL and vlog for Verilog design units.
Also, you don’t need to regenerate the std, ieee, vital22b, and verilog libraries. Also, you cannot use the
-refresh option to update libraries that were built before the 4.6 release.