svn commit: r311972 - head/lib/libnetbsd/sys

[Ngie Cooper]

Author: ngie
Date: Thu Jan 12 09:01:14 2017
New Revision: 311972
URL: https://svnweb.freebsd.org/changeset/base/311972

Log:
  Add __BIT and __BITS macros from NetBSD to help support new testcases
  
  MFC after:	1 week

Modified:
  head/lib/libnetbsd/sys/cdefs.h

Modified: head/lib/libnetbsd/sys/cdefs.h
==============================================================================
--- head/lib/libnetbsd/sys/cdefs.h	Thu Jan 12 08:53:10 2017	(r311971)
+++ head/lib/libnetbsd/sys/cdefs.h	Thu Jan 12 09:01:14 2017	(r311972)
@@ -71,4 +71,13 @@
  */
 #define	__arraycount(__x)	(sizeof(__x) / sizeof(__x[0]))
 
+/* __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) & (NBBY * sizeof(uintmax_t) - 1))))
+
+/* __BITS(m, n): bits m through n, m < n. */
+#define	__BITS(__m, __n)	\
+	((__BIT(MAX((__m), (__n)) + 1) - 1) ^ (__BIT(MIN((__m), (__n))) - 1))
+
 #endif /* _LIBNETBSD_SYS_CDEFS_H_ */