First commit.

source/mnist_loader.js

@@ -0,0 +1,27 @@
+export async function loadMNIST(device, sampleCount = 1000) {
+    async function loadFile(path) {
+        const res = await fetch(path);
+        return new Uint8Array(await res.arrayBuffer());
+    }
+
+    const imgRaw = await loadFile("../../models/train-images-idx3-ubyte");
+    const lblRaw = await loadFile("../../models/train-labels-idx1-ubyte");
+
+    const header = 16;
+    const fullCount = lblRaw.length - 8;
+    const count = Math.min(sampleCount, fullCount);
+
+    const images = new Float32Array(count * 28 * 28);
+    const labels = new Uint32Array(count);
+
+    for (let i = 0; i < count; i++) {
+        labels[i] = lblRaw[8 + i];
+        const src = header + i * 784;
+        const dst = i * 784;
+        for (let j = 0; j < 784; j++) {
+            images[dst + j] = imgRaw[src + j] / 255;
+        }
+    }
+
+    return { images, labels, count };
+}