xref: /freebsd-src/contrib/llvm-project/compiler-rt/lib/builtins/divmodti4.c (revision e8d8bef961a50d4dc22501cde4fb9fb0be1b2532)
1*e8d8bef9SDimitry Andric //===-- divmodti4.c - Implement __divmodti4 -------------------------------===//
2*e8d8bef9SDimitry Andric //
3*e8d8bef9SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*e8d8bef9SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*e8d8bef9SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*e8d8bef9SDimitry Andric //
7*e8d8bef9SDimitry Andric //===----------------------------------------------------------------------===//
8*e8d8bef9SDimitry Andric //
9*e8d8bef9SDimitry Andric // This file implements __divmodti4 for the compiler_rt library.
10*e8d8bef9SDimitry Andric //
11*e8d8bef9SDimitry Andric //===----------------------------------------------------------------------===//
12*e8d8bef9SDimitry Andric 
13*e8d8bef9SDimitry Andric #include "int_lib.h"
14*e8d8bef9SDimitry Andric 
15*e8d8bef9SDimitry Andric #ifdef CRT_HAS_128BIT
16*e8d8bef9SDimitry Andric 
17*e8d8bef9SDimitry Andric // Returns: a / b, *rem = a % b
18*e8d8bef9SDimitry Andric 
19*e8d8bef9SDimitry Andric COMPILER_RT_ABI ti_int __divmodti4(ti_int a, ti_int b, ti_int *rem) {
20*e8d8bef9SDimitry Andric   const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
21*e8d8bef9SDimitry Andric   ti_int s_a = a >> bits_in_tword_m1;                   // s_a = a < 0 ? -1 : 0
22*e8d8bef9SDimitry Andric   ti_int s_b = b >> bits_in_tword_m1;                   // s_b = b < 0 ? -1 : 0
23*e8d8bef9SDimitry Andric   a = (a ^ s_a) - s_a;                                  // negate if s_a == -1
24*e8d8bef9SDimitry Andric   b = (b ^ s_b) - s_b;                                  // negate if s_b == -1
25*e8d8bef9SDimitry Andric   s_b ^= s_a;                                           // sign of quotient
26*e8d8bef9SDimitry Andric   tu_int r;
27*e8d8bef9SDimitry Andric   ti_int q = (__udivmodti4(a, b, &r) ^ s_b) - s_b;      // negate if s_b == -1
28*e8d8bef9SDimitry Andric   *rem = (r ^ s_a) - s_a;                               // negate if s_a == -1
29*e8d8bef9SDimitry Andric   return q;
30*e8d8bef9SDimitry Andric }
31*e8d8bef9SDimitry Andric 
32*e8d8bef9SDimitry Andric #endif // CRT_HAS_128BIT
33