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AR# 44961

13.3 XST - "ERROR:HDLCompiler:1791 - "<*>.v" Line 9: Empty parameter assignment not allowed"

Description

Beginning with the 13.3 release, XST startedgenerating the following error message when it came across an extra comma at the end of the linecontaining a single parameter mapping:

"ERROR:HDLCompiler:1791 - "<*>.v" Line 9: Empty parameter assignment not allowed"

XST synthesized this line ofcode without any error message in prior versions of XST (e.g., 13.2 and earlier).

Solution

The reason for the error isdue to the presence of anextra comma at the end of line containing the single parameter mapping. Take the following piece of code as an example:

module pn_16
(
inputclk,
outputrand
);
parameter [63:0] SEED = 64'h92d9362c71427dca;

pn_gen #(
.SEED(SEED[63:0]),
)
mem_0
(
.clk(clk),
.dout(rand)
);
endmodule

In the above sample code, the extra comma at the end ofthe highlighted line of code containing the single parameter mappingcauses13.3 XST to error out with the following HDLCompiler error:

"ERROR:HDLCompiler:1791 - "<*>.v" Line 9: Empty parameter assignment not allowed"

It is not good practise toadd a comma at the end of the line containing a single parameter mapping.The following code will get synthesized correctly by 13.3 XST without an error message:

module pn_16
(
inputclk,
outputrand
);
parameter [63:0] SEED = 64'h92d9362c71427dca;

pn_gen #(
.SEED(SEED[63:0])
)
mem_0
(
.clk(clk),
.dout(rand)
);
endmodule

AR# 44961
Date Created 11/22/2011
Last Updated 05/19/2012
Status Active
Type Known Issues
Tools
  • ISE Design Suite - 13.3