continue TomCat's optimization of the tunnel

examples/wat/tunnel_opt.wat

@@ -0,0 +1,74 @@
+(module
+  (import "env" "atan2" (func $atan2 (param f32 f32) (result f32)))
+  (import "env" "time" (func $time (result f32)))
+  (import "env" "memory" (memory 4))
+  (func (export "upd")
+    (local $y i32)
+    (local $i i32) 
+    (local $x i32)
+
+    (loop $pixels
+      i32.const 1
+      local.get $i
+
+      local.get $i
+
+      i32.const 36928
+      f32.convert_i32_s
+      local.get $i
+      i32.const 320
+      i32.rem_s
+      i32.const 160
+      i32.sub
+      local.tee $x
+      local.get $x
+      i32.mul
+      local.get $i
+      i32.const 320
+      i32.div_s
+      i32.const 120
+      i32.sub
+      local.tee $y
+      local.get $y
+      i32.mul
+      i32.add
+      f32.convert_i32_s
+      f32.sqrt
+      f32.div
+      i32.const 163
+      f32.convert_i32_s
+      call $time
+      f32.mul
+      f32.add
+      i32.trunc_sat_f32_s
+
+      i32.const 163
+      f32.convert_i32_s
+      local.get $x
+      f32.convert_i32_s
+      local.get $y
+      f32.convert_i32_s
+      call $atan2
+      f32.mul
+      i32.const 64
+      f32.convert_i32_s
+      call $time
+      f32.mul
+      f32.add
+      i32.trunc_f32_s
+
+      i32.xor
+      i32.const 4
+      i32.shr_s
+      i32.const 15
+      i32.and
+      i32.store8 offset=120
+
+      i32.add
+      local.tee $i
+      i32.const 76800
+      i32.rem_s
+      br_if $pixels
+  )
+ )
+)