xref: /llvm-project/compiler-rt/lib/builtins/divmodti4.c (revision 510b6b79141cc00641369c9544489b112c4e4f43)
1c9af3402SCraig Topper //===-- divmodti4.c - Implement __divmodti4 -------------------------------===//
2c9af3402SCraig Topper //
3c9af3402SCraig Topper // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4c9af3402SCraig Topper // See https://llvm.org/LICENSE.txt for license information.
5c9af3402SCraig Topper // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6c9af3402SCraig Topper //
7c9af3402SCraig Topper //===----------------------------------------------------------------------===//
8c9af3402SCraig Topper //
9c9af3402SCraig Topper // This file implements __divmodti4 for the compiler_rt library.
10c9af3402SCraig Topper //
11c9af3402SCraig Topper //===----------------------------------------------------------------------===//
12c9af3402SCraig Topper 
13c9af3402SCraig Topper #include "int_lib.h"
14c9af3402SCraig Topper 
15c9af3402SCraig Topper #ifdef CRT_HAS_128BIT
16c9af3402SCraig Topper 
17c9af3402SCraig Topper // Returns: a / b, *rem = a % b
18c9af3402SCraig Topper 
__divmodti4(ti_int a,ti_int b,ti_int * rem)19c9af3402SCraig Topper COMPILER_RT_ABI ti_int __divmodti4(ti_int a, ti_int b, ti_int *rem) {
20c9af3402SCraig Topper   const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
21c9af3402SCraig Topper   ti_int s_a = a >> bits_in_tword_m1;                   // s_a = a < 0 ? -1 : 0
22c9af3402SCraig Topper   ti_int s_b = b >> bits_in_tword_m1;                   // s_b = b < 0 ? -1 : 0
23*510b6b79SKarl-Johan Karlsson   a = (tu_int)(a ^ s_a) - s_a;                          // negate if s_a == -1
24*510b6b79SKarl-Johan Karlsson   b = (tu_int)(b ^ s_b) - s_b;                          // negate if s_b == -1
25c9af3402SCraig Topper   s_b ^= s_a;                                           // sign of quotient
26c9af3402SCraig Topper   tu_int r;
27c9af3402SCraig Topper   ti_int q = (__udivmodti4(a, b, &r) ^ s_b) - s_b;      // negate if s_b == -1
28c9af3402SCraig Topper   *rem = (r ^ s_a) - s_a;                               // negate if s_a == -1
29c9af3402SCraig Topper   return q;
30c9af3402SCraig Topper }
31c9af3402SCraig Topper 
32c9af3402SCraig Topper #endif // CRT_HAS_128BIT
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