( ESNUG 213 Item 2 ) ---------------------------------------------- [4/5/95]
Subject: (ESNUG 211 #7 212 #1) "Synopsys & Cores: Library Wire Model Bugs"
>We had to patch the GATES library to fix some erroneous timing values...
>... we instead released a "patch" library which contained only the fixed
>cells. Then the link_library was set up as: link_library = { "*", PATCH.db,
>GATES.db, MEGA.db } ... Now, update_lib would report that everything was
>still going swimmingly. But somehow, neither I nor the customer "noticed"
>that there was no reference to wire-load in the compile logs or timing
>reports! In fact, the wire load selection table for GATES.db was completely
>ignored! ... To work around it we had the customer "update_lib" all of the
>libraries in the link_library list. update_lib may work on only the first
>library -- I never had a chance to check this out.
From: [ Synopsys R & D ]
John,
Prior to v3.3 - User could only get a wire load selection group from the first
library in the target library list which was actually used in the design.
In v3.3 - User who does nothing will have a wire load selection group picked
from the first used library in the target library list. If none are
available, a selection group will be chosen out of the first library in the
link library list. If none are available there either, auto wire load
selection is not done. In either case, wire loads in the chosen selection
group must be defined in the same library as the selection group. Since
v3.3 now supports named selection groups, the user can get a selection
group out of any library in the link library path by explicitly setting
the selection group and library:
set_wire_load -library <name> -selection_group <name>
- [ Synopsys R & D ]
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