compiler_rt/lib/ctzdi2.c

/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
 *
 *                     The LLVM Compiler Infrastructure
 *
 * This file is dual licensed under the MIT and the University of Illinois Open
 * Source Licenses. See LICENSE.TXT for details.
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __ctzdi2 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

/* Returns: the number of trailing 0-bits  */

/* Precondition: a != 0 */

COMPILER_RT_ABI si_int
__ctzdi2(di_int a)
{
    dwords x;
    x.all = a;
    const si_int f = -(x.s.low == 0);
    return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
              (f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
}
Revision:	5069
Committed:	Sat Jul 21 14:35:28 2012 UTC (11 years, 9 months ago) by laffer1
Content type:	text/plain
File size:	836 byte(s)
Log Message:	Import FreeBSD version of compiler_rt.
#	Content
1	/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
2	*
3	* The LLVM Compiler Infrastructure
4	*
5	* This file is dual licensed under the MIT and the University of Illinois Open
6	* Source Licenses. See LICENSE.TXT for details.
7	*
8	* ===----------------------------------------------------------------------===
9	*
10	* This file implements __ctzdi2 for the compiler_rt library.
11	*
12	* ===----------------------------------------------------------------------===
13	*/
14
15	#include "int_lib.h"
16
17	/* Returns: the number of trailing 0-bits */
18
19	/* Precondition: a != 0 */
20
21	COMPILER_RT_ABI si_int
22	__ctzdi2(di_int a)
23	{
24	dwords x;
25	x.all = a;
26	const si_int f = -(x.s.low == 0);
27	return __builtin_ctz((x.s.high & f) \| (x.s.low & ~f)) +
28	(f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
29	}