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Altera_Forum's avatar
Altera_Forum
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15 years ago

Can Quartus generate carry chains automatically?

Is Quartus able to infer Cyclone II carry chains automatically in synthesis from user Verilog code, or only within Altera's own library modules? I'm using 10.1SP1 web edition on Linux. I've wr...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Did you try using a + sign? I don't know how you did a ripple-carry adder but I'm guessing it might have been too low-level for synthesis to understand your intent. Just a guess. Also, open your verilog in Quartus and go to Edit -> Insert Template -> Verilog -> Full Designs -> Arithmetic. These should all get optimal synthesis(i.e. carry chain).

I haven't seen anyone manually instantiate carry_sum in many years.