--- gforth/test/gforth.fs	2009/09/25 18:52:29	1.16
+++ gforth/test/gforth.fs	2011/08/10 13:55:03	1.18
@@ -1,6 +1,6 @@
 \ test some gforth extension words
 
-\ Copyright (C) 2003,2004,2005,2006,2007 Free Software Foundation, Inc.
+\ Copyright (C) 2003,2004,2005,2006,2007,2009 Free Software Foundation, Inc.
 
 \ This file is part of Gforth.
 
@@ -95,3 +95,16 @@ t{ -5e  1e fcopysign ->  5e }t
 t{  5e -1e fcopysign -> -5e }t
 t{ -5e -1e fcopysign -> -5e }t
 \ tests involving -0e?
+
+\ ?of
+
+: sgn ( n1 -- n2 )
+    case
+	dup 0< ?of drop -1 endof
+	dup 0> ?of drop 1 endof
+	dup
+    endcase ;
+
+t{  5 sgn ->  1 }
+t{ -3 sgn -> -1 }
+t{  0 sgn ->  0 }