initial setup and overview

README.md

@@ -1,6 +1,16 @@
-[![Build Status](https://travis-ci.org/WebAssembly/spec.svg?branch=master)](https://travis-ci.org/WebAssembly/spec)
+[![Build Status](https://travis-ci.org/WebAssembly/relaxed-simd.svg?branch=master)](https://travis-ci.org/WebAssembly/relaxed-simd)
 
-# spec
+# Relaxed SIMD proposal for WebAssembly
+
+This repository is a clone of [github.com/WebAssembly/spec/](https://github.com/WebAssembly/spec/).
+It is meant for discussion, prototype specification and implementation of a proposal to
+add support for SIMD instructions with relaxed determinism requirements to WebAssembly.
+
+* See the [overview](proposals/relaxed-simd/Overview.md) for a summary of the proposal.
+
+* See the [modified spec](https://webassembly.github.io/relaxed-simd/) for details.
+
+Original `README` from upstream repository follows…
 
 This repository holds the sources for the WebAssembly draft specification
 (to seed a future

document/core/index.rst

@@ -3,7 +3,7 @@ WebAssembly Specification
 
 .. only:: html
 
-   | Release |release| (Draft, |today|)
+   | Release |release| + relaxed-simd (Draft, |today|)
 
    | Editor: Andreas Rossberg
 

document/core/util/macros.def

@@ -3,11 +3,11 @@
 .. External Standards
 .. ------------------
 
-.. |WasmDraft| replace:: https://webassembly.github.io/spec/core/
-.. _WasmDraft: https://webassembly.github.io/spec/core/
+.. |WasmDraft| replace:: https://webassembly.github.io/relaxed-simd/core/
+.. _WasmDraft: https://webassembly.github.io/relaxed-simd/core/
 
-.. |WasmIssues| replace:: https://github.com/webassembly/spec/issues/
-.. _WasmIssues: https://github.com/webassembly/spec/issues/
+.. |WasmIssues| replace:: https://github.com/webassembly/relaxed-simd/issues/
+.. _WasmIssues: https://github.com/webassembly/relaxed-simd/issues/
 
 .. |IEEE754| replace:: IEEE 754-2019
 .. _IEEE754: https://ieeexplore.ieee.org/document/8766229

proposals/relaxed-simd/Overview.md

@@ -0,0 +1,29 @@
+# Relaxed SIMD proposal
+
+## Summary
+
+This proposal adds a set of useful SIMD instructions that introduce local
+non-determinism (where the results of the instructions may vary based on
+hardware support).
+
+## Motivation
+
+Applications running on Wasm SIMD cannot take full advantage of hardware
+capabilities. There are 3 reasons:
+
+1. Instruction depends on hardware support
+2. Approximate instructions that are underspecified in hardware
+3. Some SIMD instructions penalize particular architecture
+
+See [these
+slides](https://docs.google.com/presentation/d/1Qnx0nbNTRYhMONLuKyygEduCXNOv3xtWODfXfYokx1Y/edit?usp=sharing)
+for more details.
+
+## Overview
+
+Some instructions we would like to add:
+
+- Fused Multiply Add (single rounding if hardware supports it, double rounding if not)
+- Approximate reciprocal/reciprocal sqrt
+- Relaxed Swizzle (implementation defined out of bounds behavior)
+- Relaxed Rounding Q-format Multiplication (optional saturation)