Index: /trunk/ccl/lib/format.lisp
===================================================================
--- /trunk/ccl/lib/format.lisp	(revision 906)
+++ /trunk/ccl/lib/format.lisp	(revision 907)
@@ -868,10 +868,10 @@
      (t (setq *format-index* start)
         (with-format-parameters parms ((mincol 0) (colinc 1) (minpad 0) (padchar #\space))
-          (unless (and (integerp mincol) (not (minusp mincol)))
-            (format-error "Mincol must be a non-negative integer - ~S" mincol))
+          (unless (integerp mincol)
+            (format-error "Mincol must be an integer - ~S" mincol))
           (unless (and (integerp colinc) (plusp colinc))
             (format-error "Colinc must be a positive integer - ~S" colinc))
-          (unless (and (integerp minpad) (not (minusp minpad)))
-            (format-error "Minpad must be a non-negative integer - ~S" minpad))
+          (unless (integerp minpad)
+            (format-error "Minpad must be an integer - ~S" minpad))
           (unless (characterp padchar)
             (if (typep padchar `(integer 0 #.char-code-limit))
@@ -1737,11 +1737,10 @@
 (defun format-write-field (stream string mincol colinc minpad padchar padleft)
   (unless (or (null mincol)
-              (and (integerp mincol)
-                   (not (minusp mincol))))
-    (format-error "Mincol must be a non-negative integer - ~S" mincol))
+              (integerp mincol))
+    (format-error "Mincol must be an integer - ~S" mincol))
   (unless (and (integerp colinc) (plusp colinc))
     (format-error "Colinc must be a positive integer - ~S" colinc))
-  (unless (and (integerp minpad) (not (minusp minpad)))
-    (format-error "Minpad must be a non-negative integer - ~S" minpad))
+  (unless (integerp minpad)
+    (format-error "Minpad must be an integer - ~S" minpad))
   (unless (characterp padchar)
     (if (typep padchar `(integer 0 #.char-code-limit))