xref: /minix3/sys/external/bsd/compiler_rt/dist/lib/builtins/moddi3.c (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1*0a6a1f1dSLionel Sambuc /*===-- moddi3.c - Implement __moddi3 -------------------------------------===
2*0a6a1f1dSLionel Sambuc  *
3*0a6a1f1dSLionel Sambuc  *                    The LLVM Compiler Infrastructure
4*0a6a1f1dSLionel Sambuc  *
5*0a6a1f1dSLionel Sambuc  * This file is dual licensed under the MIT and the University of Illinois Open
6*0a6a1f1dSLionel Sambuc  * Source Licenses. See LICENSE.TXT for details.
7*0a6a1f1dSLionel Sambuc  *
8*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
9*0a6a1f1dSLionel Sambuc  *
10*0a6a1f1dSLionel Sambuc  * This file implements __moddi3 for the compiler_rt library.
11*0a6a1f1dSLionel Sambuc  *
12*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
13*0a6a1f1dSLionel Sambuc  */
14*0a6a1f1dSLionel Sambuc 
15*0a6a1f1dSLionel Sambuc #include "int_lib.h"
16*0a6a1f1dSLionel Sambuc 
17*0a6a1f1dSLionel Sambuc /* Returns: a % b */
18*0a6a1f1dSLionel Sambuc 
19*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI di_int
__moddi3(di_int a,di_int b)20*0a6a1f1dSLionel Sambuc __moddi3(di_int a, di_int b)
21*0a6a1f1dSLionel Sambuc {
22*0a6a1f1dSLionel Sambuc     const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
23*0a6a1f1dSLionel Sambuc     di_int s = b >> bits_in_dword_m1;  /* s = b < 0 ? -1 : 0 */
24*0a6a1f1dSLionel Sambuc     b = (b ^ s) - s;                   /* negate if s == -1 */
25*0a6a1f1dSLionel Sambuc     s = a >> bits_in_dword_m1;         /* s = a < 0 ? -1 : 0 */
26*0a6a1f1dSLionel Sambuc     a = (a ^ s) - s;                   /* negate if s == -1 */
27*0a6a1f1dSLionel Sambuc     du_int r;
28*0a6a1f1dSLionel Sambuc     __udivmoddi4(a, b, &r);
29*0a6a1f1dSLionel Sambuc     return ((di_int)r ^ s) - s;                /* negate if s == -1 */
30*0a6a1f1dSLionel Sambuc }
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