vendor: EMSDK 6.0.6 scripts at e26beb67ef18a37d71d522d8b7096b20a4d3d0f9

bazel/hello-world/hello-world-simd.cc

@@ -0,0 +1,49 @@
+#include <wasm_simd128.h>
+
+void multiply_arrays(int* out, int* in_a, int* in_b, int size) {
+  for (int i = 0; i < size; i += 4) {
+    v128_t a = wasm_v128_load(&in_a[i]);
+    v128_t b = wasm_v128_load(&in_b[i]);
+    v128_t prod = wasm_i32x4_mul(a, b);
+    wasm_v128_store(&out[i], prod);
+  }
+}
+
+#ifdef __wasm_relaxed_simd__
+
+float dot_product_accumulate(const float* A, const float* B, int len, float initial_sum) {
+    int i = 0;
+
+    // Initialize accumulator vector with the initial sum spread across all lanes
+    // We will sum these lanes at the end.
+    v128_t acc = wasm_f32x4_splat(initial_sum);
+
+    // Main loop: process 4 elements at a time
+    // Requires len to be at least 4. If len < 4, the loop is skipped.
+    for (; i + 4 <= len; i += 4) {
+        // Load 4 floats from A and B
+        v128_t va = wasm_v128_load(&A[i]);
+        v128_t vb = wasm_v128_load(&B[i]);
+
+        // Fused Multiply-Add: acc = (va * vb) + acc
+        // Uses relaxed rounding for performance
+        acc = __builtin_wasm_relaxed_madd_f32x4(va, vb, acc);
+    }
+
+    // Horizontal add: sum the 4 lanes of the accumulator
+    // acc = {s0, s1, s2, s3}
+    // sum = s0 + s1 + s2 + s3
+    v128_t sum1 = wasm_f32x4_add(acc, wasm_i32x4_shuffle(acc, acc, 1, 0, 3, 2)); // {s0+s1, s0+s1, s2+s3, s2+s3}
+    v128_t sum2 = wasm_f32x4_add(sum1, wasm_i32x4_shuffle(sum1, sum1, 2, 3, 0, 1)); // {total, total, total, total}
+
+    float result = wasm_f32x4_extract_lane(sum2, 0);
+
+    // Handle remaining elements (tail loop)
+    for (; i < len; i++) {
+        result += A[i] * B[i];
+    }
+
+    return result;
+}
+
+#endif