1 //===-- divsi3.c - Implement __divsi3 -------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 // This file implements __divsi3 for the compiler_rt library.
11 //===----------------------------------------------------------------------===//
17 COMPILER_RT_ABI si_int __divsi3(si_int a, si_int b) {
18 const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1;
19 si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0
20 si_int s_b = b >> bits_in_word_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
25 // On CPUs without unsigned hardware division support,
26 // this calls __udivsi3 (notice the cast to su_int).
27 // On CPUs with unsigned hardware division support,
28 // this uses the unsigned division instruction.
30 return ((su_int)a / (su_int)b ^ s_a) - s_a; // negate if s_a == -1
33 #if defined(__ARM_EABI__)
34 COMPILER_RT_ALIAS(__divsi3, __aeabi_idiv)