simd.dev

An open database of SIMD intrinsics and vector data types, with drop-in tooltip tooling for the web, the terminal, and your editor.

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Search intrinsics & types

Type any part of a name — intrinsic or SIMD vector type. Multi-word terms compose with AND, so add f16 matches names containing both add and f16. You can also add filters: arch:aarch64 family:sve, or combine them: arch:aarch32 add f16.

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What's here

data

21,484 records spanning ARM (NEON / Helium / SVE / SVE2 / SME) and Intel (MMX / SSE* / AVX / AVX2 / AVX-512 / AMX) — plus 208 SIMD types. Each entry has signature, ISA family, arch, short prose description, and (where upstream provides it) pseudocode.

Generated automatically from upstream sources (ARM ACLE, Intel Intrinsics Guide XML, LLVM clang headers). Pure stdlib Python, no LLM in the loop.

simd-tooltip

Drop-in JavaScript tooltip library — one <script> tag adds hover (or click, or hover-with-?-badge) tooltips to any HTML page. Detects intrinsic names in text on the fly using caretPositionFromPoint — no DOM walk, no markup mutation by default.

~22 KB minified, ~7 KB gzipped. Lazy-loads the data file on first hover.

simd-annotate

A CLI that takes any static HTML file, scans the visible text for intrinsic and type names, and emits a self-contained, 100% offline HTML file with the library plus only the slice of the database the page actually references embedded inline.

Useful for archived posts, e-book exports, intranet docs. Pure stdlib Python.

simd-vscode

VS Code extension that surfaces the same data as a hover tooltip directly in your editor. Covers all ~22k intrinsics, including the AVX-512 and ARM NEON / SVE / SME ranges where clangd typically shows only the bare signature.

Manual install via vsce package + code --install-extension for now.

Why this exists

SIMD code is high-leverage but easy to forget. Every codebase that uses _mm256_fmadd_ps, vqtbl1q_u8, or svadd_s32_z is a codebase whose readers — including its future authors — periodically stop and look up what the intrinsic does. The reference material exists (Intel's Intrinsics Guide, ARM's developer portal, the ACLE spec), but none of it embeds well into a third-party blog post or a code review or an in-editor hover.

So this project takes the reference material that already exists, hammers it into a clean open database, and adds three thin presentation layers so you can drop intrinsic-aware tooltips into any context that takes plain HTML, plain text, or a VS Code workspace.

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