cpu (feat): store three opcodes instead of one

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

include/cpu/psr.hh

@@ -71,7 +71,7 @@ stringify(Condition cond) {
 
 class Psr {
   public:
-    // clear the reserved bits i.e, [8:27]
+    Psr() = default;
     Psr(uint32_t raw);
 
     uint32_t raw() const;