add global vars + i64 & f64 support

random.cwa

@@ -1,22 +1,24 @@
 import "env.memory" memory(4);
 
+global mut randomState: i32 = 37;
+
 fn random() -> i32 {
-    let seed = !0;
-    seed = seed ^ (seed << 13);
-    seed = seed ^ (seed >> 17);
-    seed = seed ^ (seed << 5);
-    !0 = seed;
-    seed * 625341585
+    let state: i32;
+    randomState = (state := (
+                          state := randomState ^ (randomState << 13)
+                      ) ^ (state >> 17)
+                  ) ^ (state << 5);
+    randomState * 625341585
 }
 
 fn seed(s: i32) {
-    !0 = (s + (s >>> 31)) * 2060714111;
+    randomState = (((s + !(s >> 31)) as i64 * 8445297036689579347i64) >> 31i64) as i32;
 }
 
 export fn tic(time: i32) {
     let i: i32;
     loop pixels {
-        seed(i + time / 10);
+        seed(i + (time / 100) * 320);
         i?120 = random();
         branch_if (i := i + 1) < 320*256: pixels
     }