diff --git a/wasm/build.sh b/wasm/build.sh
index e70e44f..9c04a2d 100755
--- a/wasm/build.sh
+++ b/wasm/build.sh
@@ -1,17 +1,20 @@
#!/bin/bash
-# Build quant.cpp WASM demo
+# Build quant.cpp WASM demo (multi-threaded + SIMD)
# Requires: Emscripten SDK (emcc)
#
# Usage: cd wasm && bash build.sh
# Then: python3 -m http.server 8080
# Open: http://localhost:8080
+#
+# Multi-threading requires Cross-Origin-Isolation headers.
+# coi-serviceworker.js injects them on GitHub Pages / static hosts.
set -e
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
-echo "=== Building quant.cpp WASM ==="
+echo "=== Building quant.cpp WASM (pthreads + SIMD) ==="
# Check emcc
if ! command -v emcc &>/dev/null; then
@@ -23,13 +26,14 @@ fi
echo "emcc version: $(emcc --version | head -1)"
-# Build
+# Build with pthreads + SIMD128 + ASYNCIFY
emcc "$SCRIPT_DIR/quant_wasm.c" \
-I"$PROJECT_DIR" \
-o "$SCRIPT_DIR/quant.js" \
-O3 \
-msimd128 \
-flto \
+ -pthread \
-s WASM=1 \
-s ALLOW_MEMORY_GROWTH=1 \
-s MAXIMUM_MEMORY=4GB \
@@ -38,13 +42,15 @@ emcc "$SCRIPT_DIR/quant_wasm.c" \
-s EXPORTED_RUNTIME_METHODS='["UTF8ToString","allocateUTF8","FS"]' \
-s FORCE_FILESYSTEM=1 \
-s MODULARIZE=0 \
- -s ENVIRONMENT=web \
+ -s ENVIRONMENT='web,worker' \
-s NO_EXIT_RUNTIME=1 \
-s ASSERTIONS=0 \
-s STACK_SIZE=1MB \
-s ASYNCIFY \
-s 'ASYNCIFY_IMPORTS=["emscripten_sleep"]' \
-s ASYNCIFY_STACK_SIZE=65536 \
+ -s PTHREAD_POOL_SIZE=4 \
+ -s PTHREAD_POOL_SIZE_STRICT=0 \
-lm \
-DNDEBUG \
-D__EMSCRIPTEN__ \
@@ -53,11 +59,14 @@ emcc "$SCRIPT_DIR/quant_wasm.c" \
echo ""
echo "=== Build complete ==="
-echo "Files: quant.js ($(du -h "$SCRIPT_DIR/quant.js" | cut -f1)), quant.wasm ($(du -h "$SCRIPT_DIR/quant.wasm" | cut -f1))"
+echo "Files:"
+for f in quant.js quant.wasm quant.worker.js; do
+ [ -f "$SCRIPT_DIR/$f" ] && echo " $f ($(du -h "$SCRIPT_DIR/$f" | cut -f1))"
+done
echo ""
echo "To serve locally:"
echo " cd $SCRIPT_DIR && python3 -m http.server 8080"
echo " Open http://localhost:8080"
echo ""
-echo "For HTTPS (required for SharedArrayBuffer):"
-echo " npx serve -s $SCRIPT_DIR --ssl-cert cert.pem --ssl-key key.pem"
+echo "Note: Multi-threading requires Cross-Origin-Isolation."
+echo "coi-serviceworker.js handles this automatically on GitHub Pages."
diff --git a/wasm/coi-serviceworker.js b/wasm/coi-serviceworker.js
new file mode 100644
index 0000000..ae0530b
--- /dev/null
+++ b/wasm/coi-serviceworker.js
@@ -0,0 +1,63 @@
+/*! coi-serviceworker v0.1.7 - Guido Zuidhof, licensed under MIT */
+/*
+ * Service Worker that injects Cross-Origin-Opener-Policy and
+ * Cross-Origin-Embedder-Policy headers into all responses.
+ * This enables SharedArrayBuffer on hosts that don't support
+ * custom HTTP headers (e.g., GitHub Pages).
+ *
+ * Required for WASM pthreads (multi-threaded inference).
+ */
+if (typeof window === 'undefined') {
+ // Service Worker scope
+ self.addEventListener("install", () => self.skipWaiting());
+ self.addEventListener("activate", (e) => e.waitUntil(self.clients.claim()));
+
+ self.addEventListener("fetch", (e) => {
+ // Only intercept same-origin or navigation requests
+ if (
+ e.request.cache === "only-if-cached" &&
+ e.request.mode !== "same-origin"
+ ) {
+ return;
+ }
+
+ e.respondWith(
+ fetch(e.request).then((response) => {
+ // Can't modify opaque responses
+ if (response.status === 0) return response;
+
+ const newHeaders = new Headers(response.headers);
+ newHeaders.set("Cross-Origin-Embedder-Policy", "credentialless");
+ newHeaders.set("Cross-Origin-Opener-Policy", "same-origin");
+
+ return new Response(response.body, {
+ status: response.status,
+ statusText: response.statusText,
+ headers: newHeaders,
+ });
+ }).catch((err) => {
+ console.error("coi-serviceworker fetch error:", err);
+ return new Response("Service Worker fetch error", { status: 500 });
+ })
+ );
+ });
+} else {
+ // Window scope — register the service worker
+ (async () => {
+ if (!window.crossOriginIsolated) {
+ const reg = await navigator.serviceWorker.register(
+ window.document.currentScript.src
+ );
+ if (reg.active && !navigator.serviceWorker.controller) {
+ // Service worker installed but not controlling — reload to activate
+ window.location.reload();
+ } else if (!reg.active) {
+ // Wait for the service worker to activate, then reload
+ const sw = reg.installing || reg.waiting;
+ sw.addEventListener("statechange", () => {
+ if (sw.state === "activated") window.location.reload();
+ });
+ }
+ }
+ })();
+}
diff --git a/wasm/index.html b/wasm/index.html
index 925bdc9..716d0ee 100644
--- a/wasm/index.html
+++ b/wasm/index.html
@@ -7,6 +7,8 @@
quant.cpp — LLM in Your Browser
+
+