Latch inference using dataflow analysis
AssigneeCadence Design Systems, Inc.
InventorsSzu-Tsung Cheng, Alexander Saldanha, Patrick C. McGeer, Patrick Scaglia
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Abstract
A system and method are provided for selectively inferring latch elements in a circuit design from an event-driven hardware description language (HDL) file to an event-independent format. The method includes modeling the file as a plurality of data flow equations, analyzing the plurality of equations for uninitialized variables, and placing a latch at any utilized, uninitialized variable. Control signal information for an inferred latch is also derived during the data flow analysis.
Claims9
A method of determining whether a latch is represented in an expression of a circuit using data flow analysis, the method comprising the steps of:
- identifying a set of variables Lp used in the expression;
- for a variable within the set Lp, conducting an uninitialized variable analysis for a given input signal;
- if the variable is accessed while uninitialized, inferring a latch for that variable.
A system for determining whether a latch is represented in an expression of a circuit using data flow analysis, the system comprising:
- means for identifying a set of variables Lp used in the expression;
- means for conducting, for a variable within the set Lp, an uninitialized variable analysis for a given input signal;
- and
- means for inferring, if the variable is accessed while uninitialized, a latch for that variable.
A method of inferring latch elements from an HDL file using data flow analysis;
- the method comprising the step of:
- inferring a latch if an accessed variable in an HDL expression is uninitialized for a given input signal.
A method for selectively inferring latch elements in a circuit design from an HDL file;
- the method comprising the steps of:
- modeling the file as a plurality of data flow equations;
- analyzing said equations for uninitialized variables;
- and
- placing a latch at each utilized unitialized variable.
Dependencies are inferred from the claim text.