[rustc.git] / src / compiler-rt / lib / builtins / absvsi2.c

/* ===-- absvsi2.c - Implement __absvsi2 -----------------------------------===
 *
 *                     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 __absvsi2 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

/* Returns: absolute value */

/* Effects: aborts if abs(x) < 0 */

COMPILER_RT_ABI si_int
__absvsi2(si_int a)
{
    const int N = (int)(sizeof(si_int) * CHAR_BIT);
    if (a == (1 << (N-1)))
        compilerrt_abort();
    const si_int t = a >> (N - 1);
    return (a ^ t) - t;
}
Commit	Line	Data
1a4d82fc JJ	1	/* ===-- absvsi2.c - Implement __absvsi2 -----------------------------------===
	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 __absvsi2 for the compiler_rt library.
	11	*
	12	* ===----------------------------------------------------------------------===
	13	*/
	14
	15	#include "int_lib.h"
	16
	17	/* Returns: absolute value */
	18
	19	/* Effects: aborts if abs(x) < 0 */
	20
	21	COMPILER_RT_ABI si_int
	22	__absvsi2(si_int a)
	23	{
	24	const int N = (int)(sizeof(si_int) * CHAR_BIT);
	25	if (a == (1 << (N-1)))
	26	compilerrt_abort();
	27	const si_int t = a >> (N - 1);
	28	return (a ^ t) - t;
	29	}