absvsi2.c revision 222656 
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#include "abi.h"
15
16#include "int_lib.h"
17#include <stdlib.h>
18
19/* Returns: absolute value */
20
21/* Effects: aborts if abs(x) < 0 */
22
23COMPILER_RT_ABI si_int
24__absvsi2(si_int a)
25{
26    const int N = (int)(sizeof(si_int) * CHAR_BIT);
27    if (a == (1 << (N-1)))
28        compilerrt_abort();
29    const si_int t = a >> (N - 1);
30    return (a ^ t) - t;
31}
32