( ESNUG 308 Item 3 ) ---------------------------------------------- [1/20/99]
Subject: (ESNUG 306 #3 307 #5) Bizarre 13 - 41% Area Increase W/ Aspec Libs
> I'm using Aspec libraries, and Synopsys 1998.02 and 1998.08.
>
> Even though I use no rams in my design, my design team shares a common
> setup script, therefore a "ram.db" is added into everyone's (including my)
> link_library and target_library.
>
> Here's the problem: Although I don't have any rams in my design, the areas
> increase about 15% to 40% if the *unused* Aspec RAMs are linked in!
>
> I submitted this bug to Synopsys two months ago. They re-produced the
> problem but no workarounds for me so far. They talked to Aspec and looked
> over their .lib source and report that it appears to be OK. When I tried
> all three above scenarios using Cascade libraries, I didn't have any area
> problems at all. (The main difference between Aspec libs and Cascade libs
> is that Aspec uses table lookup timing model, Cascade however uses
> piecewise linear model. I don't think this means anything, but it is a
> known difference between the two libs.)
>
> It's been two months. I can't wait any more. Did anyone run into the
> same situation? Any solutions? Thanks.
>
> - Eugene Ko
> Aureal Semiconductor
From: john brooks <jbrooks@brooktree.com>
Hi John,
We had same problem.
Our workaround was to NOT put the ram.db in the target library. You only
need this in the link library.
Thus, the ram lib won't be used during synthesis.
- John Brooks
Brooktree
|
|
