Base Instruction Class

CodeArtifact

The Base Instruction Class is an object-oriented component of a hierarchical constrained-random opcode generator for microcode stimulus generation. It holds data members, common constraints, and shared methods used by opcode-category child classes, enabling the original single large opcode class to be partitioned into smaller constrained classes for reduced memory use and improved performance.

First seen 5/24/2026

Last seen 5/25/2026

Evidence 2 chunks

Wiki v1

WIKI

Overview

The Base Instruction Class is a shared parent class used in a multi-class constrained-random instruction generator architecture. It was introduced after an initial single-class opcode generator placed constraints for all opcodes into one class. That single-class approach was flexible but created a large randomization problem for the constraint solver, with approximately 100 random variables and 800 constraint equations in the opcode class.^[1]

Role in multi-class randomization

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NEIGHBORHOOD

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LINKED ENTITIES

2 links

Opcode Category Child Class base_class_for The evidence states that opcode-category child classes contain opcode-specific constraints, while the base instruction class contains data members, methods, and constraints common to all child classes.

Synopsys VCS Constraint Solver used_in_generator_with The evidence describes the generator as using the Synopsys VCS constraint solver and discusses VCS constraint profiling for generator runtime and memory.

CITATIONS

8 sources

8 citations — click to expand

[1] Single-class opcode generator scale and trade-off Generating AMD microcode stimuli using VCS constraint solver

[2] Opcode class split for multi-class randomization Generating AMD microcode stimuli using VCS constraint solver

[3] Base Instruction Class contents Generating AMD microcode stimuli using VCS constraint solver

[4] Opcode category child-class constraints Generating AMD microcode stimuli using VCS constraint solver

[5] Hierarchical base/subclass performance benefit Generating AMD microcode stimuli using VCS constraint solver

[6] Upper-layer knob selection and subclass allocation Generating AMD microcode stimuli using VCS constraint solver

[7] Wrapper-class alternative for lower-level test control Generating AMD microcode stimuli using VCS constraint solver

[8] Two-layer opcode generator architecture Generating AMD microcode stimuli using VCS constraint solver