+;;; rewrite the test case to get the unsigned-byte 32/64
+;;; implementation even after implementing some modular arithmetic
+;;; with signed-byte 30:
+(assert (= 0 (funcall
+ (compile nil
+ '(lambda (a)
+ (declare (type (integer 4303063 101130078) a))
+ (mask-field (byte 30 2) (ash a 77))))
+ 57132532)))
+(assert (= 0 (funcall
+ (compile nil
+ '(lambda (a)
+ (declare (type (integer 4303063 101130078) a))
+ (mask-field (byte 64 2) (ash a 77))))
+ 57132532)))
+;;; and a similar test case for the signed masking extension (not the
+;;; final interface, so change the call when necessary):
+(assert (= 0 (funcall
+ (compile nil
+ '(lambda (a)
+ (declare (type (integer 4303063 101130078) a))
+ (sb-c::mask-signed-field 30 (ash a 77))))
+ 57132532)))
+(assert (= 0 (funcall
+ (compile nil
+ '(lambda (a)
+ (declare (type (integer 4303063 101130078) a))
+ (sb-c::mask-signed-field 61 (ash a 77))))
+ 57132532)))