Correctness Is a Process, Not a Property
The subject of this series is the correctness of SLEIGH processor specifications and the InSPECtor method used to test them. The final question is not whether a specification is simply “correct” or “incorrect,” but what a validation result actually warrants when the model sits beneath disassembly, decompilation, emulation, and security analysis. The answer is a bounded assurance judgment: trust is built by connecting structural reach, state-aware execution, external comparison, causal triage, and explicit limits.
That answer preserves the central relationship. SLEIGH is the model that claims how machine-code bytes should be decoded and what the selected instruction should do. Ghidra and other SLEIGH-dependent tools consume that model. InSPECtor does not replace the model or declare correctness by inspecting its syntax. It uses the model’s constructors and p-code to generate meaningful cases, then asks whether a SLEIGH-derived emulator agrees with hardware. The method makes the trust boundary visible without pretending that one experiment can eliminate it.
Trust is built across two connected paths
The first path is structural. A SLEIGH specification contains constructors, tables, fields, context transitions, attachments, precedence relationships, and semantic sections. GenSYS follows those choices instead of guessing arbitrary bytes. It fixes simple bit constraints, preserves complex relationships for solving, carries context changes into later decisions, accounts for overlapping constructors, and backtracks when a locally compatible choice cannot complete. The result is a concrete encoding associated with a represented decode path.
That path answers a necessary question: can the specification reach the instruction forms it claims to represent? It can expose an unreachable constructor, an over-constrained mode, a missing parent path, a bad prefix transition, or an operand mapping that becomes inconsistent under attachments. The answer is about the model’s structural surface. It tells a maintainer where the decoder has a path and where generation cannot find one under the configured conditions.
The second path is behavioral. The selected constructor produces p-code, and p-code expresses the operations that should read and change architectural state. GenSYS can inspect those operations to find initial registers and memory that trigger meaningful boundaries: overflow, equality, zero or negative results, unusual shifts, flag conditions, floating-point values, memory effects, and aliases. JuxtaPlayer then compares the p-code-derived emulator with a hardware reference after initializing the same instruction bytes and controllable state.
This path answers a different question: did the model’s predicted effects match the reference for this encoding, initial state, and environment? The comparison can include registers, memory, program-counter movement, and exception information. It can reveal a missing side effect, wrong width, incorrect operation order, bad default result, or an architectural special case that a neutral input would never expose.
Neither path subsumes the other. Structural reach without execution can repeatedly validate a wrong semantic description. Behavioral comparison without structural exploration can miss rare constructors, prefixes, aliases, or mode-dependent forms. Their combination is powerful because the first path identifies what the model says should be tested, while the second tests whether that claim survives contact with a processor.
The division of labor also explains why the word proxy matters. The SLEIGH-based emulator is not an independent specification of the target processor; it is the proxy whose fidelity is under examination. Hardware supplies the behavioral reference. Even then, the reference is a selected implementation and configuration, not a complete model of every vendor, microarchitectural resource, or untested sequence. Agreement is evidence for the case that was run, not a universal certificate.
A trustworthy claim must therefore preserve the chain from cause to evidence. The instruction encoding should be tied to the constructor path that generated it. The initial state should be tied to the p-code operation or architectural condition it was meant to stress. The observed difference should be tied to the fields that changed. The final diagnosis should distinguish a specification defect from an unsupported operation, an unmodeled feature, an unpredictable result, or a language limitation. Losing any of those links turns a useful observation into an ambiguous headline.