Dont care

Hiding Since non-functional CLBs and functional CLBs unused outputs can be both removed without affecting the digital design, they should be well hidden. The operations available to hide these elements are a secure hash function to randomly replace the unused CLBs, randomly connecting their inputs and outputs to nearby passing lines, and to dont-care inputs of other CLBs. These techniques make the non-functional CLBs appear like functional ones. 

This scheme is better than the previous scheme in hiding the non-functional CLBs since they cannot be simply located with connectivity property anymore. Unused CLBs appear as functional ones since their inputs and outputs are used and connected to other CLBs. However, we see that each CLB is a small size finite-state machine, therefore we can find all of its dont-care inputs by searching. Consequently we locate all the non-functional CLBs. Therefore the deletion algorithm is ... 

Embedding For all unused outputs of functional CLBs that have a multiplexer attached to the output, embed the signature bits into the multiplexer. If the multiplexer is a n-to-1 multiplexer then Llog2 nj bits can be embedded. Connect the unused outputs to dont-care inputs of other CLBs. 

Notice that for the unspecified combinations, the output is a dont care. In other words, the output can take any value for unspecified combinations. So DC, in order to optimize logic, assumes the same output for both the others case and when 01000 . In other words,... 

Can one specify dont care conditions for the condition branches of a case statement Solution... 

A typical scenario is when one cares only about certain inputs in a particular state but not die other inputs. DC does not support dont cares for case statement conditions because of simulation mismatches. In the simulation world, a string to string matching is performed and this applies to the dont.care conditions as well. 

There is no way to modify the code, other than the above mentioned approach. In Verilog you could use casex to easily check for dont cares, but in VHDL, each bit has to be specified. 

I want to make it clear that as the materials are taken down they must be dusted and put away with the greatest care. In other words, I dont want all the curtains, etc., taken down in two or three rooms at the same time and dumped somewhere while the other curtains, etc., in those rooms are being put in place. Each room must be done separately, the curtains, etc., dusted and put away and other curtains hung, etc., before another room is started. 

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