1 //===-- divmodsi4.c - Implement __divmodsi4 2 //--------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements __divmodsi4 for the compiler_rt library. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "int_lib.h" 15 16 // Returns: a / b, *rem = a % b 17 18 COMPILER_RT_ABI si_int __divmodsi4(si_int a, si_int b, si_int *rem) { 19 const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; 20 si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0 21 si_int s_b = b >> bits_in_word_m1; // s_b = b < 0 ? -1 : 0 22 a = (a ^ s_a) - s_a; // negate if s_a == -1 23 b = (b ^ s_b) - s_b; // negate if s_b == -1 24 s_b ^= s_a; // sign of quotient 25 su_int r; 26 si_int q = (__udivmodsi4(a, b, &r) ^ s_b) - s_b; // negate if s_b == -1 27 *rem = (r ^ s_a) - s_a; // negate if s_a == -1 28 return q; 29 } 30