X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fhost-alieneval.lisp;h=c78853fe332c88ffd9c1eb4e2065fb166db48feb;hb=82cd148d729c241e79c8df04b700beec1b7c55de;hp=8e619096143d02dc0b16d99492c1c6f1667a8293;hpb=79721a8731b8582ad8df664c2c4e04bd3d6090c6;p=sbcl.git

diff --git a/src/code/host-alieneval.lisp b/src/code/host-alieneval.lisp
index 8e61909..c78853f 100644
--- a/src/code/host-alieneval.lisp
+++ b/src/code/host-alieneval.lisp
@@ -666,8 +666,10 @@
   `(member t nil))
 
 (define-alien-type-method (boolean :naturalize-gen) (type alien)
-  (declare (ignore type))
-  `(not (zerop ,alien)))
+  (let ((bits (alien-boolean-type-bits type)))
+    (if (= bits sb!vm:n-word-bits)
+        `(not (zerop ,alien))
+        `(logtest ,alien ,(ldb (byte bits 0) -1)))))
 
 (define-alien-type-method (boolean :deport-gen) (type value)
   (declare (ignore type))