/*
 * University of Illinois/NCSA Open Source License
 *
 * Copyright (c) 2003-2012 University of Illinois at Urbana-Champaign.
 * All rights reserved.
 *
 * Developed by:
 *
 *     LLVM Team
 *
 *     University of Illinois at Urbana-Champaign
 *
 *     http://llvm.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * with the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimers.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimers in the
 *       documentation and/or other materials provided with the distribution.
 *
 *     * Neither the names of the LLVM Team, University of Illinois at
 *       Urbana-Champaign, nor the names of its contributors may be used to
 *       endorse or promote products derived from this Software without specific
 *       prior written permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH
 * THE SOFTWARE.
 */

/*
 * C compiler runtime logic for __ctzdi2() related builtins taken from LLVM.
 */

#include <sys/isa_defs.h>
#include <limits.h>

typedef union {
	long long all;
	struct {
#ifdef _LITTLE_ENDIAN
		unsigned low;
		int high;
#else
		int high;
		unsigned low;
#endif /* _LITTLE_ENDIAN */
	} s;
} dwords;

int
__ctzdi2(unsigned long long val)
{
	dwords x;
	x.all = val;
	const int f = -(x.s.low == 0);
	return (__builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
	    (f & ((int)(sizeof (int) * CHAR_BIT))));
}