cosmopolitan/third_party/compiler_rt/moddi3.c

34 lines
1.1 KiB
C

/* clang-format off */
/*===-- moddi3.c - Implement __moddi3 -------------------------------------===
*
* 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 __moddi3 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
STATIC_YOINK("huge_compiler_rt_license");
#include "third_party/compiler_rt/int_lib.h"
/* Returns: a % b */
COMPILER_RT_ABI di_int
__moddi3(di_int a, di_int b)
{
const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
di_int s = b >> bits_in_dword_m1; /* s = b < 0 ? -1 : 0 */
b = (b ^ s) - s; /* negate if s == -1 */
s = a >> bits_in_dword_m1; /* s = a < 0 ? -1 : 0 */
a = (a ^ s) - s; /* negate if s == -1 */
du_int r;
__udivmoddi4(a, b, &r);
return ((di_int)r ^ s) - s; /* negate if s == -1 */
}