xref: /freebsd-src/contrib/llvm-project/compiler-rt/lib/builtins/divmodti4.c (revision 5f757f3ff9144b609b3c433dfd370cc6bdc191ad)
1e8d8bef9SDimitry Andric //===-- divmodti4.c - Implement __divmodti4 -------------------------------===//
2e8d8bef9SDimitry Andric //
3e8d8bef9SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4e8d8bef9SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5e8d8bef9SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6e8d8bef9SDimitry Andric //
7e8d8bef9SDimitry Andric //===----------------------------------------------------------------------===//
8e8d8bef9SDimitry Andric //
9e8d8bef9SDimitry Andric // This file implements __divmodti4 for the compiler_rt library.
10e8d8bef9SDimitry Andric //
11e8d8bef9SDimitry Andric //===----------------------------------------------------------------------===//
12e8d8bef9SDimitry Andric 
13e8d8bef9SDimitry Andric #include "int_lib.h"
14e8d8bef9SDimitry Andric 
15e8d8bef9SDimitry Andric #ifdef CRT_HAS_128BIT
16e8d8bef9SDimitry Andric 
17e8d8bef9SDimitry Andric // Returns: a / b, *rem = a % b
18e8d8bef9SDimitry Andric 
__divmodti4(ti_int a,ti_int b,ti_int * rem)19e8d8bef9SDimitry Andric COMPILER_RT_ABI ti_int __divmodti4(ti_int a, ti_int b, ti_int *rem) {
20e8d8bef9SDimitry Andric   const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
21e8d8bef9SDimitry Andric   ti_int s_a = a >> bits_in_tword_m1;                   // s_a = a < 0 ? -1 : 0
22e8d8bef9SDimitry Andric   ti_int s_b = b >> bits_in_tword_m1;                   // s_b = b < 0 ? -1 : 0
23*5f757f3fSDimitry Andric   a = (tu_int)(a ^ s_a) - s_a;                          // negate if s_a == -1
24*5f757f3fSDimitry Andric   b = (tu_int)(b ^ s_b) - s_b;                          // negate if s_b == -1
25e8d8bef9SDimitry Andric   s_b ^= s_a;                                           // sign of quotient
26e8d8bef9SDimitry Andric   tu_int r;
27e8d8bef9SDimitry Andric   ti_int q = (__udivmodti4(a, b, &r) ^ s_b) - s_b;      // negate if s_b == -1
28e8d8bef9SDimitry Andric   *rem = (r ^ s_a) - s_a;                               // negate if s_a == -1
29e8d8bef9SDimitry Andric   return q;
30e8d8bef9SDimitry Andric }
31e8d8bef9SDimitry Andric 
32e8d8bef9SDimitry Andric #endif // CRT_HAS_128BIT
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