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sortix--sortix/libmaxsi/c++.cpp
Jonas 'Sortie' Termansen 9b79673dcb Initial version of Sortix.
2011-08-05 14:25:00 +02:00

106 lines
2 KiB
C++

/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
This file is part of LibMaxsi.
LibMaxsi is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option)
any later version.
LibMaxsi is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with LibMaxsi. If not, see <http://www.gnu.org/licenses/>.
c++.cpp
Implements required C++ stuff for use in the Sortix kernel.
******************************************************************************/
#include "platform.h"
extern "C" void __cxa_pure_virtual()
{
// This shouldn't happen. TODO: Possibly crash the kernel here.
}
#ifdef PLATFORM_X86
// TODO: These two stubs are buggy!
// Divides two 64-bit integers in O(logN). I think.
extern "C" uint64_t __udivdi3(uint64_t A, uint64_t B)
{
uint64_t ACC = 0;
uint64_t R = 0;
uint64_t PWR = 1;
uint64_t EXP = B;
while ( EXP <= A - ACC )
{
R += PWR;
ACC += EXP;
if ( 2 * EXP <= A - ACC )
{
PWR++;
EXP *= 2;
}
else if ( A - ACC < B )
{
break;
}
else
{
while ( A - ACC < EXP )
{
PWR--;
EXP /= 2;
}
}
}
return R;
}
// Mods two 64-bit integers in O(logN). I think.
extern "C" uint64_t __umoddi3(uint64_t A, uint64_t B)
{
uint64_t ACC = 0;
uint64_t R = 0;
uint64_t PWR = 1;
uint64_t EXP = B;
while ( EXP <= A - ACC )
{
R += PWR;
ACC += EXP;
if ( 2 * EXP <= A - ACC )
{
PWR++;
EXP *= 2;
}
else if ( A - ACC < B )
{
break;
}
else
{
while ( A - ACC < EXP )
{
PWR--;
EXP /= 2;
}
}
}
return A - ACC;
}
#endif