Difference between a timing arc and a combination feedback loop?

[sam33r]

Can someone please explain the difference above. Also what will cause them ?

---------- Post added at 20:24 ---------- Previous post was at 20:22 ----------

Also please explain the output of
IN = 4'b0101;

Out = IN[IN[1:0]];

what is the value of Out?

 

[jeevan.life]

Timing arc is the timing path internal to a cell. Combinational loop is something that is a loop which causes the particular cell input to stay at a particular value because of the feed back loop.

 

[qieda]

Hi,

I think
OUT is 1'b0; It is bit[1] of the input vector.

regards

 

[ljxpjpjljx]

hi sam33r ,
timing arc is the timing path for any cell or instance, Combinational loop is the dead loop which will cause simulation hang up!
OUT is 1'b0!