newlib/libc/machine/riscv/sys/string.h

   1 /* Copyright (c) 2017  SiFive Inc. All rights reserved.
   2
   3    This copyrighted material is made available to anyone wishing to use,
   4    modify, copy, or redistribute it subject to the terms and conditions
   5    of the FreeBSD License.   This program is distributed in the hope that
   6    it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
   7    including the implied warranties of MERCHANTABILITY or FITNESS FOR
   8    A PARTICULAR PURPOSE.  A copy of this license is available at
   9    http://www.opensource.org/licenses.
  10 */
  11
  12 #ifndef _SYS_STRING_H
  13 #define _SYS_STRING_H
  14
  15 static __inline unsigned long __libc_detect_null(unsigned long w)
  16 {
  17   unsigned long mask = 0x7f7f7f7f;
  18   if (sizeof (long) == 8)
  19     mask = ((mask << 16) << 16) | mask;
  20   return ~(((w & mask) + mask) | w | mask);
  21 }
  22
  23 #endif