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Timing Analysis Predicated on a topological ordering. l 1 = 1 level: l 2 = 1 x y x y z z c s g1g1 g4g4 g3g3 g2g2 g5g5 l 3 = 2 l 5 = 2 l 4 = 3.

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Presentation on theme: "Timing Analysis Predicated on a topological ordering. l 1 = 1 level: l 2 = 1 x y x y z z c s g1g1 g4g4 g3g3 g2g2 g5g5 l 3 = 2 l 5 = 2 l 4 = 3."— Presentation transcript:

1 Timing Analysis Predicated on a topological ordering. l 1 = 1 level: l 2 = 1 x y x y z z c s g1g1 g4g4 g3g3 g2g2 g5g5 l 3 = 2 l 5 = 2 l 4 = 3

2 z Timing Analysis Predicated on a topological ordering x y x y z c s arrival times 1010 (assume a delay bound of 1 time unit for each gate) l 1 = 1 l 2 = 1 g4g4 g3g3 g2g2 g5g5 l 3 = 2 l 5 = 2 l 4 = 3 g1g1 level:

3 Circuit Model Perform static analysis in the “floating-mode”. At the outset: all wires are assumed to have unknown/undefined values ( ). the primary inputs assume definite values in {0, 1}. a “controlling” input full set of “non-controlling” inputs unknown/undefined output

4 Circuit Model During the analysis, only signals driven (directly or indirectly) by the primary inputs are assigned definite values. 1    ORAND   Perform static analysis in the “floating-mode”. At the outset: all wires are assumed to have unknown/undefined values ( ). the primary inputs assume definite values in {0, 1}.

5 Circuit Model AND Up-bounded inertial delay model. each gate has delay in [ 0, t d ] Ensures monotone speed-up property.

6 Circuit Model The arrival time at a gate output is determined: either by the earliest controlling input. AND (assuming a delay bound of 1)

7 Circuit Model The arrival time at a gate output is determined: either by the earliest controlling input; AND or by the latest non-controlling input (assuming a delay bound of 1)

8 Analysis Functional Analysis: determine what is computed. Timing Analysis: determine how long it takes to compute it. level: l 1 = 1 l 2 = 1 l 3 = 2 l 5 = 2 l 4 = 3 a b a b g1g1 g2g2 g3g3 g4g4 g5g5 c c

9 Analysis Explicit analysis: ORAND Functional Analysis: determine what is computed. Timing Analysis: determine how long it takes to compute it.

10 ORAND Analysis Explicit analysis: Functional Analysis: determine what is computed. Timing Analysis: determine how long it takes to compute it.

11 ORAND m inputs explict evaluation intractable  combinations; Analysis Explicit analysis: Functional Analysis: determine what is computed. Timing Analysis: determine how long it takes to compute it.

12 ORAND Analysis Symbolic analysis: binary, multi-terminal decision diagrams ? 1313 Functional Analysis: determine what is computed. Timing Analysis: determine how long it takes to compute it.


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