Initial commit of dynamic recompiler.

Various CPU changes to support dynamic recompiler.

src/codegen_x86.h

@@ -0,0 +1,13 @@
+#define BLOCK_SIZE 0x4000
+#define BLOCK_MASK 0x3fff
+#define BLOCK_START 0
+
+#define HASH_SIZE 0x20000
+#define HASH_MASK 0x1ffff
+
+#define HASH(l) ((l) & 0x1ffff)
+
+enum
+{
+        OP_RET = 0xc3
+};