About Gtech and DesignWare library

[david_zheng]

Dear all,

I am studying Synopsys Design Compile now,can any one help to explain that the difference between Gtech library and DesignWare Library?

Thanks a lot!

David

 

[bulx]

Gtech is a virtual library. this is what your circuit first gets translated into, before it gets synthesised to technology-defined gates. It does not mean that your real target library will have these gates. It is useful in the sense you can see broadly what kind of circuit, your VHDL ends up with.

Designware library is a real implentation for a complicated function like multiplier, divider etc.. it is an function-optimized ,but technology independent, macro that gets instantiated if your code implies (or explicity instanitates) an arithmetic or some other standard function. Means you really dont need to know how to build a booth multiplier or a priority encoder etc; you just write your code so that this functionality is reqiured, synopsys will throw in the best-fit hardware implementation it knows (and you have paid for) for that function
-b

 

[funzero]

But can you tell me whether the DW library will get the same performace through various stand cell library ? or does the dW library is pre-implement circuit toplogy and synthesising just to translate them to the stand cell .

 

[bulx]

If I understand your question correctly, yes, it gives nearly the same performance (in terms of area and delay) across cell libraries with approx similar timings.

But the point is more like that with DW you can choose a good tradeoff of timing vs area, automatically for a standard arithmetic or such function . Like if your timing requirements are not that much, it can choose, say, a mutlipler of less area, and for high frequencies, it can give a big, but fast multipier.

If you have a better idea to build a better-topology multiplier, priority encoder etc etc then you need not choose DW. but like getting a 40x40 multiplier to run at 333 MHz for 0.13u technology well within reach of DW
-b