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Verilator bug in signdness of {single} #759

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veripoolbot opened this issue May 3, 2014 · 2 comments
Closed

Verilator bug in signdness of {single} #759

veripoolbot opened this issue May 3, 2014 · 2 comments
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area: wrong runtime result Issue involves an incorrect runtine result from Verilated model resolution: fixed Closed; fixed

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Author Name: Clifford Wolf (@cliffordwolf)
Original Redmine Issue: 759 from https://www.veripool.org
Original Date: 2014-05-03
Original Assignee: Wilson Snyder (@wsnyder)

Verilator a985a1f returns 11001 instead of 01001, i.e. verilator
performs sign extension even though the result of { .. } is unsigned.

     output [4:0] y;
     assign y = { -4'sd7 };
endmodule

Self-contained test case:

http://svn.clifford.at/handicraft/2014/verilatortest/test010.v

http://svn.clifford.at/handicraft/2014/verilatortest/test010.cc

http://svn.clifford.at/handicraft/2014/verilatortest/test010.sh
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Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2014-05-04T00:20:38Z

Good one. It worked with multiple concat arguments, but with just one term "{x}" was optimizing it away before it determined the sizes didn't change. Wouldn't be surprising if no one ever had a concat without multiple arguments and a signed size mismatch.

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Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2014-05-11T21:11:35Z

In 3.860.

@veripoolbot veripoolbot added area: wrong runtime result Issue involves an incorrect runtine result from Verilated model resolution: fixed Closed; fixed labels Dec 22, 2019
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area: wrong runtime result Issue involves an incorrect runtine result from Verilated model resolution: fixed Closed; fixed
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