common instruction scenario base class

CodeArtifact

A shared SystemVerilog-style base class for processor instruction scenarios that encapsulates reusable scenario methods and cross-instruction constraints. It supports constrained-random stimulus generation, directed scenarios loaded from pre-assembled traces, and controllable rules such as memory-alignment constraints that may be disabled to generate exception cases.

First seen 5/28/2026

Last seen 6/1/2026

Evidence 7 chunks

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Overview

The common instruction scenario base class is a reusable base class for processor verification scenarios. It exists because pure random instruction streams are unlikely to form useful processor programs, so user-defined scenarios need shared methods and constraints that make random instruction sequences legal, interesting, and controllable. In the cited constrained-random verification approach, operations, instructions, and instruction scenarios are modeled as classes as part of a bottom-up transaction-abstraction hierarchy.[C1]

Role in instruction-scenario modeling

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RELATIONSHIPS

6 connections

Instruction Scenario implements → 95% 2e

The common instruction scenario base class encapsulates methods and constraints for instruction scenarios.

Memory Alignment Constraint implements → 93% 2e

The common instruction scenario base class implements memory alignment rules as constraints.

Branch Scenario Generation implements → 88% 2e

The common instruction scenario base class provides constraints to handle branch scenarios.

Constraint-Based Randomization uses → 93% 1e

The common scenario base class uses constraint-based randomization to describe relationships between instruction objects.

Transaction Abstraction part of → 90% 1e

The common instruction scenario base class represents the scenario level of the transaction abstraction hierarchy.

Directed Test uses → 88% 1e

The common scenario class has a method to load directed scenarios from files.

LINKED ENTITIES

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Instruction Scenario IMPLEMENTS Extracted graph relationship

Memory Alignment Constraint IMPLEMENTS Extracted graph relationship

Constraint-Based Randomization USES Extracted graph relationship

Transaction Abstraction PART_OF Extracted graph relationship

CITATIONS

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[1] Instruction scenarios are part of a transaction-abstraction hierarchy modeled as classes, built bottom-up from operations and instructions toward stimulus descriptions. Applying Constrained-Random Verification to Microprocessors

[2] The common instruction scenario base class encapsulates useful methods shared by user-defined scenarios and can implement relationships between instruction objects as constraints, including memory-alignment constraints that may be disabled to generate misaligned load/store exception cases. Applying Constrained-Random Verification to Microprocessors

[3] Branch scenarios require constraints because random register values are unlikely to exercise forward branch taken behavior or avoid long backward-branch loops. Applying Constrained-Random Verification to Microprocessors

[4] A typical common scenario class includes a method to load directed scenarios from files containing pre-assembled program traces, supporting directed stimulus such as software-team tests. Applying Constrained-Random Verification to Microprocessors

[5] Instruction scenarios can be represented as dynamic arrays of instruction objects, with SystemVerilog foreach array constraints used for scenario-related constraints; generators may select and randomize constrained-random, directed-random, or directed scenarios. Applying Constrained-Random Verification to Microprocessors