Unwanted FF/Latch trimming!!!

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Postby Case23 » Thu Dec 09, 2010 9:19 am

hi,

i tested your code and it works fine here (quartus 8.1).
I guess your are using this code in a bigger project and the rest of the project only uses 32 bit of this registers. That would explain why xst says that the bits 32 to 63 are constant.
Case23
 
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Postby Case23 » Thu Dec 09, 2010 3:18 pm

hi,

no, there is no such option as it doesn't make sense to do it.
There is a bug in your design which makes these registers useless. Remove this bug, and the registers will stay.
Case23
 
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Postby tricky » Fri Dec 10, 2010 2:12 pm

Basically - you have inputs that are stuck at '0'. Therefore xilinx sees no use for the registers.

Find the error that is causing the inputs to be stuck at '0'.
tricky
 
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