Writing Testbenches using System Verilog下载

Writing Testbenches using System Verilog 英文原版的，学起来比较容易。 Writing Testbenches using System Verilog About the Cover xiii Preface xv Why This Book Is Important . . . . . . xvi What This Book Is About . . . . . . . . xvi What Prior Knowledge You Should Have . . . . . . . . xviii Reading Paths . . . xviii Why SystemVerilog? . . . . . . . . . . . . xix VHDL and Verilog . .xix Hardware Verification Languages . . . xx Code Examples . . . xxi For More Information . . . . . . . . . . xxii Acknowledgements . . . . . . . . . . . . xxii CHAPTER 1 What is Verification? 1 What is a Testbench? 1 The Importance of Verification . . . . . 2 Reconvergence Model . . . . . . . . . . . . 4 The Human Factor . 5 Automation . . . . . . . . . 6 Poka-Yoke . . . . . . . . . . 6 Table of Contents vi Writing Testbenches using SystemVerilog Redundancy . . . . . . . . . 7 What Is Being Verified? . . . . . . . . . . 7 Equivalence Checking 8 Property Checking . . . 9 Functional Verification . . . . . . . . . . . . 10 Functional Verification Approaches .11 Black-Box Verification . . . . . . . . . . . . 11 White-Box Verification . . . . . . . . . . . . 13 Grey-Box Verification . . . . . . . . . . . . 14 Testing Versus Verification . . . . . . . 15 Scan-Based Testing . 16 Design for Verification . . . . . . . . . . . . 17 Design and Verification Reuse . . . . 18 Reuse Is About Trust . 18 Verification for Reuse 19 Verification Reuse . . . 19 The Cost of Verification . . . . . . . . . 20 Summary . . . . . . . . 22 CHAPTER 2 Verification Technologies 23 Linting . . . . . . . . . 24 The Limitations of Linting Technology 25 Linting SystemVerilog Source Code . . 27 Code Reviews . . . . . . 29 Simulation . . . . . . . 29 Stimulus and Response . . . . . . . . . . . . 30 Event-Driven Simulation . . . . . . . . . . 31 Cycle-Based Simulation . . . . . . . . . . . 33 Co-Simulators . . . . . . 35 Verification Intellectual Property . . . 38 Waveform Viewers 39 Code Coverage . . . 41 Statement Coverage . 43 Path Coverage . . . . . 44 Expression Coverage 45 FSM Coverage . . . . . 46 What Does 100 Percent Code Coverage Mean? . . . . . 48 Functional Coverage . . . . . . . . . . . . 49 Writing Testbenches using SystemVerilog vii Coverage Points . . . . 51 Cross Coverage . . . . . 53 Transition Coverage . 53 What Does 100 Percent Functional Coverage Mean? . 54 Verification Language Technologies 55 Assertions . . . . . . . 57 Simulated Assertions . 58 Formal Assertion Proving . . . . . . . . . 59 Revision Control . . 61 The Software Engineering Experience 62 Configuration Management . . . . . . . . 63 Working with Releases . . . . . . . . . . . . 65 Issue Tracking . . . . 66 What Is an Issue? . . . 67 The Grapevine System . . . . . . . . . . . . 68 The Post-It System . . 68 The Procedural System . . . . . . . . . . . . 69 Computerized System 69 Metrics . . . . . . . . . . 71 Code-Related Metrics 71 Quality-Related Metrics . . . . . . . . . . . 73 Interpreting Metrics . 74 Summary . . . . . . . . 76 CHAPTER 3 The Verification Plan 77 The Role of the Verification Plan . . 78 Specifying the Verification . . . . . . . . . 78 Defining First-Time Success . . . . . . . . 79 Levels of Verification . . . . . . . . . . . 80 Unit-Level Verification . . . . . . . . . . . . 81 Block and Core Verification . . . . . . . . 82 ASIC and FPGA Verification . . . . . . . 84 System-Level Verification . . . . . . . . . . 84 Board-Level Verification . . . . . . . . . . . 85 Verification Strategies . . . . . . . 86 Verifying the Response . . . . . . . . . . . . 86 From Specification to Features . . . . 87 Block-Level Features 90 System-Level Features . . . . . . . . . . . . 91 Table of Contents viii Writing Testbenches using SystemVerilog Error Types to Look For . . . . . . . . . . . 91 Prioritize . . . . . . . . . . 92 Design for Verification . . . . . . . . . . . . 93 Directed Testbenches Approach . . . 96 Group into Testcases . 96 From Testcases to Testbenches . . . . . . 98 Verifying Testbenches 99 Measuring Progress 100 Coverage-Driven Random-Based Approach . . . . . . 101 Measuring Progress 101 From Features to Functional Coverage . . . . . . . . . . . 103 From Features to Testbench . . . . . . . 105 From Features to Generators . . . . . . 107 Directed Testcases . . 109 Summary . . . . . . . .111 CHAPTER 4 High-Level Modeling 113 High-Level versus RTL Thinking . .113 Contrasting the Approaches . . . . . . . 115 You Gotta Have Style! . . . . . . . . . . .117 A Question of Discipline . . . . . . . . . . 117 Optimize the Right Thing . . . . . . . . . 118 Good Comments Improve Maintainability . . . . . . . . . 121 Structure of High-Level Code . . . . 122 Encapsulation Hides Implementation Details . . . . . . 122 Encapsulating Useful Subprograms . 125 Encapsulating Bus-Functional Models . . . . . . . . . . . . 127 Data Abstraction . 130 2-state Data Types . 131 Struct, Class . . . . . . 131 Union . . . . . . . . . . . 134 Arrays . . . . . . . . . . . 139 Queues . . . . . . . . . . 141 Associative Arrays . 143 Files . . . . . . . . . . . . 145 From High-Level to Physical-Level . 146 Object-Oriented Programming . . . 147 Classes . . . . . . . . . . 147 Inheritance . . . . . . . 153 Writing Testbenches using SystemVerilog ix Polymorphism . . . . . 156 The Parallel Simulation Engine . . . 159 Connectivity, Time and Concurrency 160 The Problems with Concurrency . . . . 160 Emulating Parallelism on a Sequential Processor . . . 162 The Simulation Cycle . . . . . . . . . . . . 163 Parallel vs. Sequential . . . . . . . . . . . 169 Fork/Join Statement 170 The Difference Between Driving and Assigning . . . . . 173 Race Conditions . . . . . . . . . . . 176 Read/Write Race Conditions . . . . . . . 177 Write/Write Race Conditions . . . . . . 180 Initialization Races . 182 Guidelines for Avoiding Race Conditions . . . . . . . . . . 183 Semaphores . . . . . . . 184 Portability Issues 186 Events from Overwritten Scheduled Values . . . . . . . . 186 Disabled Scheduled Values . . . . . . . . 187 Output Arguments on Disabled Tasks 188 Non-Re-Entrant Tasks . . . . . . . . . . . . 188 Static vs. Automatic Variables . . . . . 193 Summary . . . . . . . 196 CHAPTER 5 Stimulus and Response 197 Reference Signals 198 Time Resolution Issues . . . . . . . . . . . 199 Aligning Signals in Delta-Time . . . . . 201 Clock Multipliers . . 203 Asynchronous Reference Signals . . . 205 Random Generation of Reference Signal Parameters 206 Applying Reset . . . . 208 Simple Stimulus . 212 Applying Synchronous Data Values . 212 Abstracting Waveform Generation . . 214 Simple Output . . . 216 Visual Inspection of Response . . . . . . 217 Producing Simulation Results . . . . . . 217 Minimizing Sampling . . . . . . . . . . . . 219 Visual Inspection of Waveforms . . . . 220 Table of Contents x Writing Testbenches using SystemVerilog Self-Checking Testbenches . . . . . . . . 221 Input and Output Vectors . . . . . . . . . 221 Golden Vectors . . . . 222 Self-Checking Operations . . . . . . . . . 224 Complex Stimulus . . . . . . . . . . . . 227 Feedback Between Stimulus and Design . . . . . . . . . . 228 Recovering from Deadlocks . . . . . . . 228 Asynchronous Interfaces . . . . . . . . . . 231 Bus-Functional Models . . . . . . . . . 234 CPU Transactions . . 234 From Bus-Functional Tasks to Bus-Functional Model 236 Physical Interfaces . 238 Configurable Bus-Functional Models . . . . . . . . . . . . 243 Response Monitors . . . . . . . . . . . . 246 Autonomous Monitors . . . . . . . . . . . . 249 Slave Generators . . 253 Multiple Possible Transactions . . . . . 255 Transaction-Level Interface . . . . . . 258 Procedural Interface vs Dataflow Interface . . . . . . . . 259 What is a Transaction? . . . . . . . . . . . 263 Blocking Transactions . . . . . . . . . . . 265 Nonblocking Transactions . . . . . . . . 265 Split Transactions . . 267 Exceptions . . . . . . . . 270 Summary . . . . . . . 278 CHAPTER 6 Architecting Testbenches 279 Verification Harness . . . . . . . . . . . 280 Design Configuration . . . . . . . . . . 284 Abstracting Design Configuration . . 285 Configuring the Design . . . . . . . . . . . 288 Random Design Configuration . . . . . 290 Self-Checking Testbenches . . . . . . 292 Hard Coded Response . . . . . . . . . . . 294 Data Tagging . . . . . 295 Reference Models . . 297 Transfer Function . . 299 Scoreboarding . . . . . 300 Integration with the Transaction Layer . . . . . . . . . . . 302 Writing Testbenches using SystemVerilog xi Directed Stimulus 304 Random Stimulus . 307 Atomic Generation . 307 Adding Constraints . 312 Constraining Sequences . . . . . . . . . . 316 Defining Random Scenarios . . . . . . . 320 Defining Procedural Scenarios . . . . 322 System-Level Verification Harnesses . . . . . . . . . . . 327 Layered Bus-Functional Models . . . . 328 Summary . . . . . . . 331 CHAPTER 7 Simulation Management 333 Transaction-Level Models . . . . . . . 333 Transaction-Level versus Synthesizable Models . . . . 334 Example of Transaction-Level Modeling . . . . . . . . . . 335 Characteristics of a Transaction-Level Model . . . . . . 337 Modeling Reset . . . . 341 Writing Good Transaction-Level Models . . . . . . . . . . 342 Transaction-Level Models Are Faster . . . . . . . . . . . . 347 The Cost of Transaction-Level Models . . . . . . . . . . . . 348 The Benefits of Transaction-Level Models . . . . . . . . . 349 Demonstrating Equivalence . . . . . . . 351 Pass or Fail? . . . . . 352 Managing Simulations . . . . . . . . . . 355 Configuration Management . . . . . . . 355 Avoiding Recompilation or SDF Re-Annotation . . . . . 358 Output File Management . . . . . . . . . 361 Seed Management . . 364 Regression . . . . . . 365 Running Regressions 366 Regression Management . . . . . . . . . . 367 Summary . . . . . . . 370 APPENDIX A Coding Guidelines 371 File Structure . . . . 372 Filenames . . . . . . . . 375 Style Guidelines . . 376 Table of Contents xii Writing Testbenches using SystemVerilog Comments . . . . . . . . 376 Layout . . . . . . . . . . . 378 Structure . . . . . . . . . 380 Debugging . . . . . . . . 383 Naming Guidelines . . . . . . . . . . . . 384 Capitalization . . . . . 384 Identifiers . . . . . . . . 386 Constants . . . . . . . . 389 Portability Guidelines . . . . . . . . . . 391 APPENDIX B Glossary 397 Index 401