Within X-Amin, the Support for a signal is simply the top-level inputs or Flip-Flop outputs that drive a signal. Determining the support of a signal is necessary for controlling the other analysis methods such as Eval and Prove, but it also provides insight as to the logic structure of a signal.

For example, given the following HDL code:

module comp1 (clk, rst, a, b, ld1, ld2, z);

   input clk, rst, a, b, ld1, ld2;
   output z;
   
   reg d;
   always @(posedge clk or posedge rst)
      if (!rst)
         d <= 0;
      else if (ld1)
         d <= a & b;
      else if (ld2)
         d <= a | b;
      else 
         d <= a ^ b;

    assign z = d;
       
endmodule

The support for signal 'z' would be:

> read comp1.v
Current Namespace: :comp1

> link
Namespace ':comp1' linked

> puts [support d]
a b ld1 ld2 rst

Note that in command-line mode, the support command returns a list. Therefore, in the example the list is printed using puts.

To determine the support of a signal in GUI mode, select the signal's parent component in the Component Window then select the signal in the Signal window. Then, use the Command menu (Command->Support) or the Signals Window popup menu (right mouse button->Support) to generate the support list for the selected signal.

 

support Command

Support information can also be generated using the support command entered in the GUI Command Entry box or on the command line in command-line mode. The support command format is:

SYNTAX
 (list) support
   [-hier]
   <sig>
   

ARGUMENTS
 -hier Use hierarchical names for all inputs

 <sig> Produce a list of inputs for this signal.