diff --git a/src/vim9execute.c b/src/vim9execute.c
index f154249..8b614bf 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1970,6 +1970,20 @@
 		}
 		break;
 
+	    // List functions
+	    case ISN_DEF:
+		if (iptr->isn_arg.string == NULL)
+		    list_functions(NULL);
+		else
+		{
+		    exarg_T ea;
+
+		    CLEAR_FIELD(ea);
+		    ea.cmd = ea.arg = iptr->isn_arg.string;
+		    define_function(&ea, NULL);
+		}
+		break;
+
 	    // jump if a condition is met
 	    case ISN_JUMP:
 		{
@@ -3371,6 +3385,15 @@
 		}
 		break;
 
+	    case ISN_DEF:
+		{
+		    char_u *name = iptr->isn_arg.string;
+
+		    smsg("%4d DEF %s", current,
+					   name == NULL ? (char_u *)"" : name);
+		}
+		break;
+
 	    case ISN_JUMP:
 		{
 		    char *when = "?";