Progress on early subsumption

Signed-off-by: gothictomato <gothictomato@pm.me>

rng.h

@@ -0,0 +1,15 @@
+#pragma once
+#include "types.h"
+
+typedef struct {
+    bool ready;
+    u64 state[8];
+} rngstate;
+
+void seed(rngstate* s, u64 seed);
+u64 ru64(rngstate* s);
+u32 ru32(rngstate* s);
+f64 rf64(rngstate* s);
+f32 rf32(rngstate* s);
+void jump(rngstate* s);
+u64 ru64pow(rngstate* s, u64 max);