# wgsl-conformance — WGSL's integer semantics on a GPU

The vectors an adapter passes before it runs a graph of a decode at `decode-equivalence`
([`extensions/determinism-tiers.md`](../extensions/determinism-tiers.md) §5, *Claiming
the tier on a GPU*, item 5): every integer operation a kernel may use (the rules check's
rule 7 keeps the kernels inside the suite), on `i32`, `u32` and two-component vectors of
them where a kernel uses those, at the cases WGSL defines at run time and the languages it
is translated into leave open — wrapping addition, subtraction, multiplication and
negation; division and remainder by zero and of the most negative `i32` by −1; shift
amounts from 0 to 40 and past them; `clamp` with its bounds in and out of order;
`abs`, `sign`, the bit counts and positions; bit fields at and past the word; the
conversions between `i32`, `u32` and `bool`.

**Provenance.** Written by `wai/wai-ops-gpu`'s `wai-wgsl-vectors` binary from
`wai_ops_gpu::semantics::reference`, which states each result from the text of WGSL
(W3C Candidate Recommendation Draft, 21 October 2026, §8.8, §8.10, §17.5), not from a
shader. No case comes from a device.

## Layout

- `integer.jsonl` — one JSON object per operation, in the order of its `code`: `op`, its
  name; `code`, the operation's number in `wai-ops-gpu/src/wgsl/semantics.wgsl`; `wgsl`,
  the expression evaluated, with `a`, `b`, `c`, `d` the operands as `u32` and `ia` … `id`
  their bits as `i32`; and `cases`, each `[a, b, c, d, result]` as eight lowercase
  hexadecimal digits, followed by `"unguarded"` for a case the module of item 4 never
  reaches (a shift amount of 32 or more, `clamp` bounds out of order). A vector
  operation's result is its two components folded into one word,
  `x ^ (y × 0x9E3779B9)` modulo 2^32.

## Equivalence

An adapter conforms when, for every case not marked `unguarded`, the word it computes
for the operation on the operands, read from memory at run time, is `result`. Results on
`unguarded` cases are reported, and do not decide conformance.

The file is checked against the reference natively (`wai-ops-gpu/tests/semantics.rs`),
under Node (`wai-ops-gpu/browser/semantics_reference.mjs`) and in a browser page
(`wai-ops-gpu/browser/run.mjs`), the last two running the reference compiled to wasm32.