1 //===-- moddi3.c - Implement __moddi3 -------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements __moddi3 for the compiler_rt library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "int_lib.h"
14 
15 // Returns: a % b
16 
17 COMPILER_RT_ABI di_int __moddi3(di_int a, di_int b) {
18   const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
19   di_int s = b >> bits_in_dword_m1; // s = b < 0 ? -1 : 0
20   b = (b ^ s) - s;                  // negate if s == -1
21   s = a >> bits_in_dword_m1;        // s = a < 0 ? -1 : 0
22   a = (a ^ s) - s;                  // negate if s == -1
23   du_int r;
24   __udivmoddi4(a, b, &r);
25   return ((di_int)r ^ s) - s; // negate if s == -1
26 }
27