cursed bit slice helper

src/core/gb/Cpu.hpp

@@ -2,5 +2,33 @@
 #include <common.hpp>
 
 namespace natsukashii::core {
-struct Cpu {};
+template <class A, class B>
+struct RegisterPair {
+  A low;
+  B high;
+  auto operator=(const u16& rhs) {
+    low = rhs & 0xff;
+    high = rhs >> 8;
+    return *this;
+  }
+};
+
+union RegF {
+  struct {
+    unsigned z:1;
+    unsigned n:1;
+    unsigned h:1;
+    unsigned c:1;
+    unsigned:4;
+  };
+  u8 raw;
+};
+
+struct Cpu {
+private:
+  RegisterPair<u8, RegF> af;
+  RegisterPair<u8, u8> bc;
+  RegisterPair<u8, u8> de;
+  RegisterPair<u8, u8> hl;
+};
 }