Representation of delay expressions.
This is a product type introduced by defprod.
- rise — vl-expr
- Rising delay.
- fall — vl-expr
- Falling delay.
- high — vl-maybe-expr
- High-impedence delay or charge decay time.
WARNING. We have not paid much attention to delays, and our
transformations probably do not handle them properly.
Delays are mainly discussed in 7.14 and 5.3, with some other discussion in
6.13 and the earlier parts of Section 7. In short:
- A "delay expression" can be an arbitrary expression. Of particular note,
mintypmax expression such as 1:2:3 mean "the delay is at least 1, usually
2, and at most 3."
- Up to three delay expressions are associated with each gate. These are,
- a "rise delay",
- a "fall delay", and
- for regular gates, a "high impedence" delay;
for triregs, a "charge decay time" delay
The parser does not attempt to determine (3) in some cases, so it may be
left as nil. Simulators that care about this will need to carefully
review the rules for correctly computing these delays.
- Fixing function for vl-gatedelay structures.
- Basic equivalence relation for vl-gatedelay structures.
- Recognizer for vl-gatedelay structures.
- Basic constructor macro for vl-gatedelay structures.
- Get the high field from a vl-gatedelay.
- Get the rise field from a vl-gatedelay.
- Get the fall field from a vl-gatedelay.
- Modifying constructor for vl-gatedelay structures.