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3 years ago

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Quartus Pro 22.2 SystemVerilog: argument of size should be an identifier

.DATA_WIDTH ( $size({2'b0, 2'b0, 2'b0, 4'b0}) ) Quartus issues an error at Design Analysis Error(16845): Verilog HDL error at xxx.sv(270): argument of size should be an identifier It s...

ShengN_altera
3 years ago
Hi,

Check this https://www.intel.com/content/www/us/en/docs/programmable/683236/22-2/verilog-and-systemverilog-synthesis-support.html so latest SystemVerilog supported is SystemVerilog-2012. Then can refer to IEEE Standard 1800-2012 check here http://www.ece.uah.edu/~gaede/cpe526/2012%20System%20Verilog%20Language%20Reference%20Manual.pdf (page 604) under section 20.7 Array querying functions. You can see array_identifier is mentioned. There are some examples under that section as well for your reference.

This code can be synthesized in simulator. I tested in Questa Starter Edition with no problem. So means this is something supported in testbench. If so should be no problem too as testbench normally is not included in Quartus tool for compilation. Vivado 2021.2 still fails to synthesize $size but able to synthesize $bits. Check the images attached.

Thanks,

Best Regards,

Sheng

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Super Contributor

3 years ago

Hi,

Check this,

An identifier in Verilog and SystemVerilog is the user-specified name of some object, such as the name of a module, wire, variable, or function.

Therefore, I generally believe that you have to give a identifier to the array before $size it.

Check this http://courses.eees.dei.unibo.it/LABMPHSENG/wp-content/uploads/2016/02/SystemVerilog_3.1a.pdf (page 351)

Check this also https://stackoverflow.com/questions/33653958/how-to-get-the-number-of-elements-in-an-array-in-systemverilog

Besides, I further test with other synthesis tool and getting the error. So I don't think this is a bug. Check the image attached.

Thanks,

Best Regards,

Sheng

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Contributor

3 years ago

Does the specs of your link has anything to do with Quartus? Does QP follow these specs? Please provide an official Intel link or reference to it.

Interesting, I do not get the error with Questa https://www.edaplayground.com/x/8yaS

And I do not get the error with Vivado 2021.2 using a more complication expression.

Please refer to the actual SV specs: IEEE 1800-2017 20.7 Array query functions.

array_expression, data_type are allowed. array_expression is expression. And it looks like expression can be a concatenation operator.

I tested with $bits() and Quartus doesn't seem to complain, that's very strange since all these functions have the same definition in the specs.

Nevertheless, I might be wrong but I'd need more convincing arguments.

Regards,