xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/divmoddi4.c (revision d89ec533011f513df1010f142a111086a0785f09)
13cab2bb3Spatrick //===-- divmoddi4.c - Implement __divmoddi4 -------------------------------===//
23cab2bb3Spatrick //
33cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
43cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information.
53cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
63cab2bb3Spatrick //
73cab2bb3Spatrick //===----------------------------------------------------------------------===//
83cab2bb3Spatrick //
93cab2bb3Spatrick // This file implements __divmoddi4 for the compiler_rt library.
103cab2bb3Spatrick //
113cab2bb3Spatrick //===----------------------------------------------------------------------===//
123cab2bb3Spatrick 
133cab2bb3Spatrick #include "int_lib.h"
143cab2bb3Spatrick 
153cab2bb3Spatrick // Returns: a / b, *rem = a % b
163cab2bb3Spatrick 
__divmoddi4(di_int a,di_int b,di_int * rem)173cab2bb3Spatrick COMPILER_RT_ABI di_int __divmoddi4(di_int a, di_int b, di_int *rem) {
18*d89ec533Spatrick   const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
19*d89ec533Spatrick   di_int s_a = a >> bits_in_dword_m1;                   // s_a = a < 0 ? -1 : 0
20*d89ec533Spatrick   di_int s_b = b >> bits_in_dword_m1;                   // s_b = b < 0 ? -1 : 0
21*d89ec533Spatrick   a = (a ^ s_a) - s_a;                                  // negate if s_a == -1
22*d89ec533Spatrick   b = (b ^ s_b) - s_b;                                  // negate if s_b == -1
23*d89ec533Spatrick   s_b ^= s_a;                                           // sign of quotient
24*d89ec533Spatrick   du_int r;
25*d89ec533Spatrick   di_int q = (__udivmoddi4(a, b, &r) ^ s_b) - s_b;      // negate if s_b == -1
26*d89ec533Spatrick   *rem = (r ^ s_a) - s_a;                               // negate if s_a == -1
27*d89ec533Spatrick   return q;
283cab2bb3Spatrick }
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