diff --git a/hoax.tal b/hoax.tal
index 30ccea7..9b24257 100644
--- a/hoax.tal
+++ b/hoax.tal
@@ -164,7 +164,7 @@
 ( addition of the given 16-bit integer. )
 ( the sign of the 16-bit integer to add is assumed )
 ( to be the same as the original number. )
-@shift-and-add ( num$ $add -> res$ )
+@shift-and-add ( num$ add* -> res$ )
     STH2                             ( num$ [add*] )
     DUP2 #8000 EQU2 ,&iszero JCN     ( num$ [add*] )
     DUP2 #7fff GTH2 ,&literal JCN    ( num$ )
@@ -182,9 +182,9 @@
     ;make-obj JMP2                   ( res$ )
     &literal                         ( num$ [add*] )
     #7fff AND2                       ( n* [add*] )
-    DUP2 #4000 GTH2 ,&negative JCN   ( n* [add*] )
+    DUP2 #3fff GTH2 ,&negative JCN   ( n* [add*] )
     #30 ,&create JMP                 ( n* 30 [add*] )
-    &iszero JMP2r                    ( zero$ [add*] )
+    &iszero STH2r ;u16-to-num JMP2   ( res$ )
     &error POP POP2 ;error JMP2      ( <ERROR> )
     &negative                        ( n* [add*] )
     #8000 SWP2 SUB2 #38              ( abs* 38 [add*] )