Verification Technologies IBM Haifa Labs Formal Specification Using Sugar 2.0 Cindy Eisner September 2002

HRLHRL Sugar 2.0 Overview  Declarative language for specification of hardware  Concise, intuitive formalism to reason about behavior over time  Combines  temporal logic and  regular expressions  under a convenient layer of user-friendly syntactic sugar  Sugar is used as:  easy-to-read but precise specification  input to formal verification  source of automatically generated checkers for simulation

HRLHRL Sugar 2.0 History  1994  Syntactic sugaring of CTL for RuleBase model checker  1995  Addition of regular expressions  1997  Automatic generation of simulation monitors ________________________________________________  2001  Move to linear (LTL-based) semantics  2002  Selected by Accellera for IEEE standardization Sugar 1.0 Sugar 2.0

HRLHRL Track Record (Sugar 1.0)  IBM products:  Main Frame line (S/390)  Midrange line (AS/400)  Workstation line (RS/6000)  PC line (Netfinity)  Super Computers (ASCI)  ASIC/OEM business  External licensees  University program

HRLHRL Sugar 2.0 Sugar The Language Boolean Temporal Verification Modeling

HRLHRL Sugar 2.0 The Temporal Layer Boolean Temporal Verification Modeling

HRLHRL Sugar 2.0 Simple Invariants  If data_en is de-asserted, then data_out must be de- asserted as well. always (!data_en -> !data_out)  Signals ena and enb are never asserted simultaneously. never (ena & enb)

HRLHRL Sugar 2.0 Relations Over Time  If req is asserted, then ack must be asserted the following cycle. always (req -> next ack)  If req is asserted, ack must be asserted four cycles later. always (req -> next[4] ack)  If req is asserted, ack must be asserted some time in the future. always (req -> eventually! ack)

HRLHRL Sugar 2.0 Relations Over Time, cont.  Whenever a high priority request is received, the next grant should be to a high priority requester. always (hi_pri_req -> next_event(grant)(dst=hi_pri))  Whenever a request is issued, signal last_ready must be asserted on the fourth assertion of signal ready. always (req -> next_event(ready)[4](last_ready))

HRLHRL Sugar 2.0 Regular Expressions  If req is asserted, then eventually we must see an ack that is not aborted. always (req -> eventually! {ack ; !abortin}) ac k aborti n re q

HRLHRL Sugar 2.0 Regular Expressions, cont.  A sequence of req followed by ack should be followed by a full data transaction: an assertion of start_trans, followed by eight consecutive data transfers, followed by the assertion of end_trans. always {req;ack} |=> {start_trans;data[*8];end_trans} dat a endtran s starttran s ac k re q

HRLHRL Sugar 2.0 Regular Expressions, cont.  A sequence of req followed by ack should be followed by a full data transaction: an assertion of start_trans, followed by eight (not necessarily consecutive) data transfers, followed by the assertion of end_trans. always {req;ack} |=> {start_trans;data[=8];end_trans} starttrans ack req data endtrans

HRLHRL Sugar 2.0 Hardware clocks  Consider only cycles in which the clock ticks always (req -> next[4] (clk) ac k clk re q

HRLHRL Sugar 2.0 Hardware clocks, cont.  Support for multiply-clocked designs always (p -> next clkq q i p clkp

HRLHRL Sugar 2.0 Hardware resets  Synchronous reset always ({req;ack} |-> {start;data[*8];end} abort (clk)  Asynchronous reset always (({req;ack} |-> (clk)) abort reset)

HRLHRL Sugar 2.0 Standardization: Status  Endorsed publicly by many EDA vendors, including:  Cadence  Mentor Graphics  Co-Design Automation  0-In Design Automation  Novas Software  Accellera recommendation will be submitted to IEEE by year end 2002  Real Intent  TransEDA  Verplex  Veritable  Structured Design Verification

HRLHRL Sugar 2.0 CompanyToolFunction IBM RuleBase Model Checker IBM FoCs Generator of Simulation Monitors NoBug Consulting S2E Specification Compiler TransEDA VN-Property DX Dynamic Property Checker Cadence Verification Cockpit Dynamic + Static Property Checking Avery TestWizard Testbench Automation Tool TNI/Valiosys imPROVE-HDL Model Checker Esterel Esterel Suite Full-flow solution for design Model Checker 0-InCheckerWareLibrary of Protocol Checkers Tool Support

HRLHRL Sugar 2.0 Sugar home page  More information available on the Sugar home page at:  Complete definition  Tutorial  Sugar parser  more