add reprod examples for issues

reprod/9_nested_lvalues.core_desc

@@ -0,0 +1,21 @@
+// Nexted Lvalues not implemented (seems to be in Treenail)
+
+InstructionSet Zbb {
+    architectural_state {
+        unsigned int XLEN=32;
+        const register unsigned<32> XLEN_R = 32;
+        register unsigned<XLEN> X[32] [[is_main_reg]];
+    }
+    instructions {
+        ZIP [[enable=XLEN==32]] {
+            encoding: 12'b000010001111 :: rs1[4:0] :: 3'b001 :: rd[4:0] :: 7'b0010011;
+            assembly: "{name(rd)}, {name(rs1)}";
+            behavior: {
+                       for(unsigned int i = 0; i<=XLEN/2-1; i++){
+                            X[rd][2*i] = X[rs1][i];
+                            X[rd][2*i+1] = X[rs1][i+XLEN/2];
+                        }
+                    }
+        }
+    }
+}