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楼主 |
发表于 2012-5-24 08:39:45
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是的,net肯定不能,这是我在synopsys的solvnet上当下来的,你可以看看:
Question:
I have a net in my design that I want to preserve during place_opt/route_opt.
I use set_dont_touch to define a dont_touch attribute on this net. But as this net is going to different logical hierarchies, optimization is adding buffers on the segments of the net where I did not define dont_touch.
Doesn't dont_touch propagate through the hierarchy? What I can do to preseve such nets?
Answer:
dont_touch doesn't propagate through the hierarchies. So if your design has a net going inside different logical hierarchies, it will have different hierarchical segments (each segment with a different full name).
In such cases, if you define dont_touch on a single segment, it will not propagate through the logical hierarchy, and only that single net segment will be dont_touch. Optimization is free to buffer other segments.
If you want to prevent this, you need to define set_dont_touch on all those segments.
However, it may be difficult to find all such segments. So here are few other options you may want to consider: |
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