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Daniel Boulby318e7a52022-10-21 20:20:52 +01001//===-- divmoddi4.c - Implement __divmoddi4 -------------------------------===//
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 __divmoddi4 for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
Lionel Debieve6bda5472020-01-02 11:09:03 +010012
13#include "int_lib.h"
14
Daniel Boulby318e7a52022-10-21 20:20:52 +010015// Returns: a / b, *rem = a % b
Lionel Debieve6bda5472020-01-02 11:09:03 +010016
Daniel Boulby318e7a52022-10-21 20:20:52 +010017COMPILER_RT_ABI di_int __divmoddi4(di_int a, di_int b, di_int *rem) {
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
Manish Pandey9320bd52023-11-06 16:45:14 +000021 a = (du_int)(a ^ s_a) - s_a; // negate if s_a == -1
22 b = (du_int)(b ^ s_b) - s_b; // negate if s_b == -1
Daniel Boulby318e7a52022-10-21 20:20:52 +010023 s_b ^= s_a; // sign of quotient
24 du_int r;
25 di_int q = (__udivmoddi4(a, b, &r) ^ s_b) - s_b; // negate if s_b == -1
26 *rem = (r ^ s_a) - s_a; // negate if s_a == -1
27 return q;
Lionel Debieve6bda5472020-01-02 11:09:03 +010028}