[src/trunk]: src/sys/sys mask the shift by __n with NBBY*sizeof(uintmax-t)-1

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/586745c073be
branches:  trunk
changeset: 326584:586745c073be
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Feb 05 00:18:09 2014 +0000

description:
mask the shift by __n with NBBY*sizeof(uintmax-t)-1
to suppress the following diagnostic from clang:
error: shift count >= width of type [-Werror,-Wshift-count-overflow]
    PAR_ATTR            = __BITS(63,56),// F=0 memory attributes
                          ^~~~~~~~~~~~~
src/sys/sys/cdefs.h:554:4: note: expanded from macro '__BITS'
        ((__BIT(MAX((__m), (__n)) + 1) - 1) ^ (__BIT(MIN((__m), (__n))) - 1))
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/sys/sys/cdefs.h:550:73: note: expanded from macro '__BIT'
    (((uintmax_t)(__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (uintmax_t)(__n)))
                                                                        ^  ~~~~~~~~~~~~~~~~

diffstat:

 sys/sys/cdefs.h |  4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diffs (18 lines):

diff -r cc9eea575d13 -r 586745c073be sys/sys/cdefs.h
--- a/sys/sys/cdefs.h   Tue Feb 04 22:48:26 2014 +0000
+++ b/sys/sys/cdefs.h   Wed Feb 05 00:18:09 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cdefs.h,v 1.116 2013/10/25 14:54:25 apb Exp $  */
+/*     $NetBSD: cdefs.h,v 1.117 2014/02/05 00:18:09 matt Exp $ */
 
 /*
  * Copyright (c) 1991, 1993
@@ -547,7 +547,7 @@
 #ifndef __ASSEMBLER__
 /* __BIT(n): nth bit, where __BIT(0) == 0x1. */
 #define        __BIT(__n)      \
-    (((uintmax_t)(__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (uintmax_t)(__n)))
+    (((uintmax_t)(__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (uintmax_t)(__n & (NBBY * sizeof(uintmax_t) - 1))))
 
 /* __BITS(m, n): bits m through n, m < n. */
 #define        __BITS(__m, __n)        \