1 //===-- divdi3.c - Implement __divdi3 -------------------------------------===// 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 __divdi3 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 __divdi3(di_int a, di_int b) { 18 const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1; 19 di_int s_a = a >> bits_in_dword_m1; // s_a = a < 0 ? -1 : 0 20 di_int s_b = b >> bits_in_dword_m1; // s_b = b < 0 ? -1 : 0 21 a = (a ^ s_a) - s_a; // negate if s_a == -1 22 b = (b ^ s_b) - s_b; // negate if s_b == -1 23 s_a ^= s_b; // sign of quotient 24 return (__udivmoddi4(a, b, (du_int *)0) ^ s_a) - s_a; // negate if s_a == -1 25 } 26