modti3.c revision 263763 
1/* ===-- modti3.c - Implement __modti3 -------------------------------------===
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 __modti3 for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15#include "int_lib.h"
16
17#ifdef CRT_HAS_128BIT
18
19tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
20
21/*Returns: a % b */
22
23ti_int
24__modti3(ti_int a, ti_int b)
25{
26    const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
27    ti_int s = b >> bits_in_tword_m1;  /* s = b < 0 ? -1 : 0 */
28    b = (b ^ s) - s;                   /* negate if s == -1 */
29    s = a >> bits_in_tword_m1;         /* s = a < 0 ? -1 : 0 */
30    a = (a ^ s) - s;                   /* negate if s == -1 */
31    ti_int r;
32    __udivmodti4(a, b, (tu_int*)&r);
33    return (r ^ s) - s;                /* negate if s == -1 */
34}
35
36#endif /* CRT_HAS_128BIT */
37