SystemVerilog Random Sequence Construct

Concept

The SystemVerilog random sequence construct is described in the evidence as the upper layer of a constrained-random opcode generator architecture, where weighted knobs control the distribution of high-level generated items. In the cited AMD/Synopsys microcode-stimulus generator, this construct works with a lower opcode-class layer randomized under additional constraints and weights.

First seen 5/26/2026

Last seen 6/5/2026

Evidence 1 chunks

Wiki v1

WIKI

Overview

The SystemVerilog random sequence construct is used in the cited generator architecture as a high-level mechanism for controlling randomized stimulus generation. In the AMD/Synopsys microcode-stimulus generator, the opcode generator has two layers: an upper layer implemented with a SystemVerilog random sequence construct, and a lower layer made up of an opcode class that is randomized with additional constraints and weights supplied by the upper layer. [C1]

Role in constrained-random stimulus generation

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RELATIONSHIPS

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Hierarchical Constrained-Random Test Generation ← uses 95% 3e

The upper layer of the generator uses a SystemVerilog random sequence construct with weighted knobs.

Opcode Generator ← uses 95% 2e

The opcode generator's upper layer is implemented using a SystemVerilog random sequence construct.

hierarchical constrained-random stimulus generation ← uses 93% 1e

The upper layer of the generator uses a SystemVerilog random sequence construct.

LINKED ENTITIES

2 links

Synopsys VCS Constraint Solver used_with The evidence describes using the Synopsys VCS constraint solver and states that the solver applies weights to the generator layer.

Constrained Random Verification used_in The evidence frames the architecture as a hierarchical constrained-random approach for microcode stimulus generation.

CITATIONS

5 sources

5 citations — click to expand

[1] The opcode generator has an upper layer implemented using a SystemVerilog random sequence construct with weighted knobs, and a lower opcode-class layer randomized with additional constraints and weights. Generating AMD microcode stimuli using VCS constraint solver

[2] Automated random test generators are used to create microcode test sequences and distribute stimuli across meaningful opcode and instruction-attribute values. Generating AMD microcode stimuli using VCS constraint solver

[3] SystemVerilog constraint-language constructs provide a concise format for describing microcode instruction attribute combinations and controlling value distributions for fields. Generating AMD microcode stimuli using VCS constraint solver

[4] A single-class opcode generator is flexible but can be slow because the solver sees many random variables and constraints; the cited opcode class had about 100 random variables and 800 constraint equations. Generating AMD microcode stimuli using VCS constraint solver

[5] Using a base class with global constraints and subclasses for related opcode groups partitioned constraints hierarchically, reducing memory requirements and increasing performance. Generating AMD microcode stimuli using VCS constraint solver