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US6446243B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Method for functional verification of VLSI circuit designs utilizing reusable functional blocks or intellectual property cores

Assignee: Synopsys Inc
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Filing: 1999-04-23
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Granted: 2002-09-03
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Expires: 2019-04-23
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Abstract

Abstract Computer-assisted apparatus/method functionally verifies circuit design through automatic generation of verification rules from reusable functional block or IP core using logic simulator and input stimuli. Rule base captures set of design states or scenarios.

Inventors

  • 👤 Yen-Son Huang
  • 👤 Chia-Huei Lee
  • 👤 Changson Teng

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 12:16
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/32; G06F30/33; G06F2115/00; G06F2115/08

Claims Analysis

Total Claims: 21
Claim 1
Independent Claim 132 words
A method for functional verification of circuit designs using reusable blocks or intellectual property cores, the method comprising steps of: providing one or more functional block or intellectual property core circuit design; generating from the provided function blocks or intellectual property core circuit designs a rule base; and verifying according to the rule base a functionality of an integrated circuit comprising the provided functional blocks or intellectual property core circuit designs, wherein the generating step comprises the steps of: categorizing one or more logic included in the provided functional blocks or intellectual property core circuit designs into a control, memory, register or datapath portion; and grouping logic of the control portion into a plurality of finite state machines (FSMS) in a manner that substantially minimizes a number of interactions among the FSMS.
Claim 2
Independent Claim 132 words
A method for functional verification of circuit designs using reusable blocks or intellectual property cores, the method comprising steps of: providing one or more functional block or intellectual property core circuit design; generating from the provided function blocks or intellectual property core circuit designs a rule base; and verifying according to the rule base a functionality of an integrated circuit comprising the provided functional blocks or intellectual property core circuit designs, wherein the generating step comprises the steps of: categorizing one or more logic included in the provided functional blocks or intellectual property core circuit designs into a control, memory, register or datapath portion; and grouping logic of the control portion into a plurality of finite state machines (FSMS) in a manner that substantially minimizes a number of interactions among the FSMS.
Claim 3
Dependent Claim 94 words
The method of claim 1 wherein the grouping step comprises the steps of: identifying FSMs in the control portion; constructing a connectivity graph representing one or more connecting signal paths associated with the identified FSMs; and combining selected ones of the identified FSMs having one or more relatively short signal path lengths to provide a reduced number of FSMs, the FSMs being combined in a manner that substantially minimizes a number of interactions between FSMs, the combined FSMs being defined by one or more storage elements and a combinational complexity along the signal paths.
Claim 4
Dependent Claim 33 words
The method of claim 2 further comprising the step of: generating one or more coverage rules automatically from the provided functional blocks or intellectual property core circuit designs associated with said combined FSMs.
Claim 5
Dependent Claim 21 words
The method of claim 3 wherein: the coverage rules are determined using a logic simulator and a set of test vectors.
Claim 6
Dependent Claim 53 words
The method of claim 4 wherein: the coverage rules are determined according to the following steps: running a simulation using a hardware design language specification associated with a super FSM grouping and the test vector set; collecting simulation results; and deriving the coverage rules from a constructed state or state transition utilization table.
Claim 7
Independent Claim 150 words
A method for functionally verifying a design of a logic circuit comprising interacting logic including flip-flops, combinational logic and other logic that can be characterized as implementing finite state machines (FSMs), the method comprising the steps of: a. identifying a plurality of FSMs implemented by the other logic of the logic circuit; b. processing the design to determine for each identified FSM all states of the FSM that are reachable from an initial state of the FSM; c. processing the design to perform a simulation of logic circuit behavior and producing simulation results representing the logic circuit behavior; d. processing the simulation results to determine states visited by each remaining FSM; and e. comparing the visited states determined at step d to the reachable states determined at step b to determine whether any identified FSM failed to visit any of its reachable states during the simulation performed at step c.
Claim 8
Independent Claim 150 words
A method for functionally verifying a design of a logic circuit comprising interacting logic including flip-flops, combinational logic and other logic that can be characterized as implementing finite state machines (FSMs), the method comprising the steps of: a. identifying a plurality of FSMs implemented by the other logic of the logic circuit; b. processing the design to determine for each identified FSM all states of the FSM that are reachable from an initial state of the FSM; c. processing the design to perform a simulation of logic circuit behavior and producing simulation results representing the logic circuit behavior; d. processing the simulation results to determine states visited by each remaining FSM; and e. comparing the visited states determined at step d to the reachable states determined at step b to determine whether any identified FSM failed to visit any of its reachable states during the simulation performed at step c.
Claim 9
Dependent Claim 153 words
The method in accordance with claim 6 wherein step a comprises the substeps of: a1. processing the design to identify a set of FSMs implemented by the other logic of the logic circuit; a2. processing the design to compute a pair interaction strength for pairs of identified FSMs, wherein the pair interaction strength of each pair of FSMs is an estimate of a rate at which the FSMs of the pair are likely to interact with one another via signal paths therebetween; a3. redefining a pair of the identified FSMs having a pair interaction strength within a predetermined range, along with any flip-flops or combinational logic in any signal path interconnecting the pair of identified FSMs, as being a single FSM, thereby to reduce a total number of identified FSMs by one; and a4. repeating steps a2 and a3 until each identified FSM pair has a pair interaction strength within the predetermined range.
Claim 10
Dependent Claim 66 words
The method in accordance with claim 7 wherein the pair interaction strength of a pair of FSMs is a function of a number of signals each FSM of the pair receives from combinational logic forming signal paths between the FSMs of the pair and a number of signals each FSM of the pair transmits to combinational logic forming signal paths between the FSMs of the pair.
Claim 11
Dependent Claim 32 words
The method in accordance with claim 8 wherein the pair interaction strength of a pair of FSMs is also a function of a number of states of each FSM of the pair.
Claim 12
Dependent Claim 36 words
The method in accordance with claim 8 wherein the pair interaction strength of a pair of FSMs is also a function of a number of flip-flops included in signal paths between the FSMs of the pair.
Claim 13
Dependent Claim 66 words
The method in accordance with claim 7 wherein the pair interaction strength of a pair of FSMs is a function of a number of signals each FSM of the pair receives from combinational logic forming signal paths between the FSMs of thy pair and a number of signals each FSM of the pair transmits to combinational logic forming signal paths between the FSMs of the pair.
Claim 14
Dependent Claim 32 words
The method in accordance with claim 11 herein the pair interaction strength of a pair of FSMs is also a function of a number of states of each FSM of the pair.
Claim 15
Independent Claim 179 words
A method of functionally verifying a design of a logic circuit comprising interacting logic including flip-flops and combinational logic and other logic that may be characterized as implementing finite state machines (FSMs), the method comprising the steps of: a. processing the design to identify a set of FSMs implemented by the other logic of the logic circuit; b. processing the design to compute a pair interaction strength for pairs of identified FSMs, wherein the pair interaction strength of each pair of FSMs is a number representing an estimate of a rate at which the FSMs of the pair are likely to interact with one another via signal paths therebetween; c. redefining a pair of the FSMs having a pair interaction strength within a particular range, along with any flip-flops or combinational logic in any signal path interconnecting the pair of identified FSMs, as being a single FSM, thereby to reduce a total number of identified FSMs by one; and d. repeating steps b and c until each identified FSM pair has a pair interaction strength within the particular range.
Claim 16
Independent Claim 179 words
A method of functionally verifying a design of a logic circuit comprising interacting logic including flip-flops and combinational logic and other logic that may be characterized as implementing finite state machines (FSMs), the method comprising the steps of: a. processing the design to identify a set of FSMs implemented by the other logic of the logic circuit; b. processing the design to compute a pair interaction strength for pairs of identified FSMs, wherein the pair interaction strength of each pair of FSMs is a number representing an estimate of a rate at which the FSMs of the pair are likely to interact with one another via signal paths therebetween; c. redefining a pair of the FSMs having a pair interaction strength within a particular range, along with any flip-flops or combinational logic in any signal path interconnecting the pair of identified FSMs, as being a single FSM, thereby to reduce a total number of identified FSMs by one; and d. repeating steps b and c until each identified FSM pair has a pair interaction strength within the particular range.
Claim 17
Dependent Claim 35 words
The method in accordance with claim 13 further comprising the step of: e. processing the design to determine for each remaining FSM all states of the FSM that are accessible from that FSM's initial state.
Claim 18
Dependent Claim 47 words
The method in accordance with claim 14 further comprising the steps of: f. processing the design to perform a simulation of logic circuit behavior and producing simulation results representing the logic circuit behavior; and g. processing the simulation results to determine states visited by each remaining FSM.
Claim 19
Dependent Claim 66 words
The method in accordance with claim 14 wherein the pair interaction strength of a pair of FSMs is a function of a number of signals each FSM of the pair receives from combinational logic forming signal paths between the FSMs of the pair and a number of signals each FSM of the pair transmits to combinational logic forming signal paths between the FSMs of the pair.
Claim 20
Dependent Claim 32 words
The method in accordance with claim 16 wherein the pair interaction strength of a pair of FSMs is also a function of a number of states of each FSM of the pair.
Claim 21
Dependent Claim 36 words
The method in accordance with claim 17 wherein the pair interaction strength of a pair of FSMs is also a function of a number of flip-flops included in signal paths between the FSMs of the pair.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2005-09-02 2006-03-04 2006-09-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2009-09-02 2010-03-04 2010-09-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2013-09-02 2014-03-04 2014-09-03 $7700.00 Window Closed / Lapsed

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