Using datasets with ModelSim commands

Multiple datasets can be opened when the simulator is invoked by specifying more than one vsim -view <filename> option. By default the dataset prefix will be the filename of the WLF file. A different dataset name can also be specified as an optional qualifier to the vsim -view switch on the command line using the following syntax:

-view <dataset>=<filename>  

For example: vsim -view foo=vsim.wlf

Design regions and signal names can be fully specified over multiple WLF files by using the dataset name as a prefix in the path. For example:

sim:/top/alu/out 
view:/top/alu/out 
golden:.top.alu.out 

Dataset prefixes are not required unless more than one dataset is open, and you want to refer to something outside the default dataset. When more than one dataset is open, ModelSim will automatically prefix names in the Wave and List window with the dataset name. You can change this default by selecting Edit > Display Properties (Wave window) and
Prop > Display Props (List window).

ModelSim designates one of the datasets to be the "active" dataset, and refers all names without dataset prefixes to that dataset. The active dataset is displayed in the context path at the bottom of the Main window. When you select a design unit in a dataset's Structure tab, that dataset becomes active automatically. Alternatively, you can use the Dataset Browser or the environment command to change the active dataset.

ModelSim remembers a "current context" within each open dataset. You can toggle between the current context of each dataset using the environment command, specifying the dataset without a path. For example:

env foo: 

sets the active dataset to foo and the current context to the context last specified for foo. The context is then applied to any unlocked windows.

The current context of the current dataset (usually referred to as just "current context") is used for finding objects specified without a path.

The Signals window can be locked to a specific context of a dataset. Being locked to a dataset means that the window will update only when the content of that dataset changes. If locked to both a dataset and a context (e.g., test: /top/foo), the window will update only when that specific context changes. You specify the dataset to which the window is locked by selecting File > Environment (Signals window).

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