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1 /* ===-- divti3.c - Implement __divti3 -------------------------------------===
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 __divti3 for the compiler_rt library.
11  *
12  * ===----------------------------------------------------------------------===
13  */
14 
15 #if __x86_64
16 
17 #include "int_lib.h"
18 
19 tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
20 
21 /* Returns: a / b */
22 
23 ti_int
__divti3(ti_int a,ti_int b)24 __divti3(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_a = a >> bits_in_tword_m1;           /* s_a = a < 0 ? -1 : 0 */
28     ti_int s_b = b >> bits_in_tword_m1;           /* s_b = b < 0 ? -1 : 0 */
29     a = (a ^ s_a) - s_a;                         /* negate if s_a == -1 */
30     b = (b ^ s_b) - s_b;                         /* negate if s_b == -1 */
31     s_a ^= s_b;                                  /* sign of quotient */
32     return (__udivmodti4(a, b, (tu_int*)0) ^ s_a) - s_a;  /* negate if s_a == -1 */
33 }
34 
35 #endif
36