diff --git a/C_C++/manual_unrolling.c b/C_C++/manual_unrolling.c
new file mode 100644
index 0000000..cddee4c
--- /dev/null
+++ b/C_C++/manual_unrolling.c
@@ -0,0 +1,18 @@
+// @BAKE gcc $@ -o $*.out -O0 -ggdb
+signed main() {
+    char * src = "hey";
+    char dest[4];
+    int n = 0;
+    int j = 0;
+    int i = 0;
+    // Duff [8, 13] used this to provide a manual version of loop unrolling for older compilers and hardware:
+    switch(n & 0x3) {
+      do {
+        case 0: dest[i++] = src[j++];
+        case 1: dest[i++] = src[j++];
+        case 2: dest[i++] = src[j++];
+        case 3: dest[i++] = src[j++];
+      } while (j < n);
+    }
+    return 0;
+}