llvm-project/compiler-rt/lib/divti3.c

36 lines
1.2 KiB
C

/* ===-- divti3.c - Implement __divti3 -------------------------------------===
*
* The LLVM Compiler Infrastructure
*
* This file is distributed under the University of Illinois Open Source
* License. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*
* This file implements __divti3 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#if __x86_64
#include "int_lib.h"
tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
/* Returns: a / b */
ti_int
__divti3(ti_int a, ti_int b)
{
const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
ti_int s_a = a >> bits_in_tword_m1; /* s_a = a < 0 ? -1 : 0 */
ti_int s_b = b >> bits_in_tword_m1; /* s_b = b < 0 ? -1 : 0 */
a = (a ^ s_a) - s_a; /* negate if s_a == -1 */
b = (b ^ s_b) - s_b; /* negate if s_b == -1 */
s_a ^= s_b; /* sign of quotient */
return (__udivmodti4(a, b, (tu_int*)0) ^ s_a) - s_a; /* negate if s_a == -1 */
}
#endif