US 2010/0251199 A1Published application

Method and system for automated convergence of ternary simulation by saturation of deep gates

AssigneeInternational Buisness Machines Corporation

InventorsJason R. Baumgartner, Michael L. Case, Geert Janssen, Hari Mony

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method, system and computer program product for X-Saturated ternary simulation based reduction. An X-Saturated ternary simulation (XSTS) utility, which executes on a computer system, receives design information, where the design information includes a netlist. The XSTS utility initializes one or more data structures and/or variables and simulates, in a ternary fashion, the netlist at a time value by applying logical X values to all RANDOM gates of the netlist and to registers marked X_SATURATED. For each register of the netlist XSTS utility: determines whether or not the register departs from its expected prefix behavior, and if the register departs from its expected prefix behavior, the register is marked as X_SATURATED and the current state is updated with an X value upon the register. XSTS utility can store the current state in a data structure and can use the information from the data structure to simplify the design.

Claims19

Dependent claims

A method for simplifying at least a portion of an integrated circuit embodied by a netlist, comprising:

(a) setting a current state;
(b) simulating, in a ternary fashion, the netlist at a time value by applying logical X values to all RANDOM gates of the netlist and to registers marked X_SATURATED of all registers of the netlist;
(c) for each register of the netlist, performing:
determining whether or not the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior;
and
if the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior:
marking the register as X_SATURATED;
and
updating the current state with an X value upon the register;
(d) searching for the current state in a hash table;
(e) determining whether or not the current state was found in the hash table;
(f) if the current state was found in the hash table, setting a converged value to one;
(g) if the current state was not found in the hash table, inserting the current state into the hash table;
(h) determining whether or not one or more resources are exceeded;
(i) if the one or more resources are not exceeded:
incrementing the time value by one;
and
repeating from step (a);
and
(j) if the one or more resources are exceeded:
determining whether or not the converged value is not zero;
if the converged value is zero, indicating that the netlist could not be simplified;
and
if the converged value is not zero:
simplifying the netlist using information from the hash table;
and
outputting the simplified netlist.

24 more elements

A system for simplifying at least a portion of an integrated circuit embodied by a netlist, comprising:

a processor;
a memory medium coupled to the processor;
and
a utility including instructions, which when executed on the processor, provides logic for performing the functions of:
(a) setting a current state;
(b) simulating, in a ternary fashion, the netlist at a time value by applying logical X values to all RANDOM gates of the netlist and to registers marked X_SATURATED of all registers of the netlist;
(c) for each register of the netlist, performing:
determining whether or not the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior;
and
if the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior:
marking the register as X_SATURATED;
and
updating the current state with an X value upon the register;
(d) searching for the current state in a hash table;
(e) determining whether or not the current state was found in the hash table;
(f) if the current state was found in the hash table, setting a converged value to one;
(g) if the current state was not found in the hash table, inserting the current state into the hash table;
(h) determining whether or not one or more resources are exceeded;
(i) if the one or more resources are not exceeded:
incrementing the time value by one;
and
repeating from step (a);
and
(j) if the one or more resources are exceeded:
determining whether or not the converged value is not zero;
if the converged value is zero, indicating that the netlist could not be simplified;
and
if the converged value is not zero:
simplifying the netlist using information from the hash table;
and
outputting the simplified netlist.

28 more elements

A computer program product, comprising:

a computer-readable medium;
and
program instructions stored on said computer-readable medium that when executed on a processing system, cause the processing system to perform the functions of:
(a) setting a current state;
(b) simulating, in a ternary fashion, a netlist at a time value by applying logical X values to all RANDOM gates of the netlist and to registers marked X_SATURATED of all registers of the netlist;
(c) for each register of the netlist, performing:
determining whether or not the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior;
and
if the register is not already marked as X_SATURATED and the register is found to depart from its expected prefix behavior:
marking the register as X_SATURATED;
and
updating the current state with an X value upon the register;
(d) searching for the current state in a hash table;
(e) determining whether or not the current state was found in the hash table;
(f) if the current state was found in the hash table, setting a converged value to one;
(g) if the current state was not found in the hash table, inserting the current state into the hash table;
(h) determining whether or not one or more resources are exceeded;
(i) if the one or more resources are not exceeded:
incrementing the time value by one;
and
repeating from step (a);
and
(j) if the one or more resources are exceeded:
determining whether or not the converged value is not zero;
if the converged value is zero, indicating that the netlist could not be simplified;
and
if the converged value is not zero:
simplifying the netlist using information from the hash table;
and
outputting the simplified netlist.

27 more elements

Dependencies are inferred from the claim text.