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TimeQuest Analyzer: "~DUPLICATE"

Altera_Forum
Honored Contributor II
1,111 Views

Hi there, 

 

tl;dr: What does the postfix "~DUPLICATE" means in TimeQuest and why is it added? 

 

I have some timing violations which I try to pin point via TimeQuest Analyzer. In the Path summaries of the problematic paths, I see a lot of i.e. "signalx", but also a lot of "signalx~DUPLICATE" (see also to real-life examples below). When I right click those nodes and view them in the RTL viewer (Locate Node -> Locate in RTL Viewer), they both "signalx" as "signalx~DUPLICATE" seem to refer to the same flipflop. In the RTL viewer I am also unable to locate the register "signalx~DUPLICATE". Does anybody know what this "~DUPLICATE" prefix means and why it is added to certain signals? 

 

Cheers, 

Wobbert 

 

From: soc_system_final:u0|custom_fifo_final:fifo_57|writepointer~DUPLICATE To: soc_system_final:u0|custom_fifo_final:fifo_57|readpointer~DUPLICATE  

or 

From: soc_system_final:u0|custom_fifo_final:fifo_57|writepointer~DUPLICATE To: soc_system_final:u0|custom_fifo_final:fifo_57|readpointer
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2 Replies
Altera_Forum
Honored Contributor II
152 Views

~duplicate is where it has duplicated a register, probably with a high fan-out, probably because it thought it was going to affect timing. There is a synth setting where you can set the maximum fan-out of a register. If it goes over this, it will create a duplicate to handle the extra fan-out.

Altera_Forum
Honored Contributor II
152 Views

Ah, makes sense now. Thanks a lot!

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