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How to Remove Constant Multiplication Optimization?

Kyle
Beginner
441 Views

Hi all,

 

I am looking to disable the optimization done when multiplying by a constant. I have DSP blocks available that I want to reuse instead of having the operation mapped to logic. I am using Quartus II 15.0.

 

I've:

  • tried calling an IP block with the generic "lpm_hint => "DEDICATED_MULTIPLIER_CIRCUITRY=YES, MAXIMIZE_SPEED=0","
  • looked through the options under "Assignments -> Settings -> Compiler Settings -> Advanced Settings"
  • searched through the forums.

All to no avail. Any help is appreciated. Thanks!

0 Kudos
2 Replies
ak6dn
Valued Contributor III
84 Views

If the block is written to be fully general at the Verilog/VHDL level, why do you care that in a particular instance, when you feed it constants, that Quartus does implementation optimization? Each time you instantiate the block, Quartus will look at all the inputs/outputs, and if inputs are constants, it will optimize around that. And for unused outputs the logic will be discared (by default, can be suppressed). Why do you care if Quartus is doing this?

Vicky1
Employee
84 Views

Hi,

Could you please provide the below information?

device used

IPs used

are you using Qsys or IP Catalog?

any screen shot

Thanks,

Vikas

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