teak-llvm/compiler-rt/lib/builtins/divdi3.c
Petr Hosek 0ba22f51d1 [builtins] Use single line C++/C99 comment style
Use the uniform single line C++/99 style for code comments.

This is part of the cleanup proposed in "[RFC] compiler-rt builtins
cleanup and refactoring".

Differential Revision: https://reviews.llvm.org/D60352

llvm-svn: 359411
2019-04-28 22:47:49 +00:00

26 lines
1.1 KiB
C

//===-- divdi3.c - Implement __divdi3 -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements __divdi3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// Returns: a / b
COMPILER_RT_ABI di_int __divdi3(di_int a, di_int b) {
const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
di_int s_a = a >> bits_in_dword_m1; // s_a = a < 0 ? -1 : 0
di_int s_b = b >> bits_in_dword_m1; // s_b = b < 0 ? -1 : 0
a = (a ^ s_a) - s_a; // negate if s_a == -1
b = (b ^ s_b) - s_b; // negate if s_b == -1
s_a ^= s_b; // sign of quotient
return (__udivmoddi4(a, b, (du_int *)0) ^ s_a) - s_a; // negate if s_a == -1
}