manes/runtime.cpp

   1 /* Quarn OS
   2  *
   3  * Runtime functions for C++
   4  *
   5  * Copyright (C) 2008-2009 Pawel Dziepak
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 /* This is set of functions that are needed to correctly execute code written
  24  * in the C++ programming language. Main part of this file is runtime_start()
  25  * function, which calls all constructors of global and static objects.
  26  */
  27
  28 #include "manes/error.h"
  29
  30 /* Calls constructors of all global and static objects */
  31 void runtime_start() {
  32         extern int _bss_end;
  33         extern int _bss;
  34
  35         const unsigned int end = 0x80000;
  36
  37         unsigned int bss_size = (unsigned int)&_bss_end - (unsigned int)&_bss + 0x10000;
  38         char *bss = (char*)&_bss;
  39
  40         char *to = (char*)0x200000;
  41         char *from = (char*)0x100000;
  42         for (unsigned int i = 0; i < end; i++)
  43                 to[i] = from[i];
  44
  45         /* Clear bss section */
  46         for (unsigned int i = 0; i < bss_size; i++)
  47                 bss[i] = 0;
  48
  49         /* Threre is a constructors list: __CTOR_LIST__
  50          * First entry of the list is the number of constructors.
  51          * Other entries are pointers to the constructors.
  52          * Everyting is set in the linker script
  53          */
  54         extern void (*__CTOR_LIST__)();
  55         void (**constr)() = &__CTOR_LIST__;
  56         int number = *(int*)constr;
  57
  58         for (int i = 1; i <= number; i++) (constr[i])();
  59 }
  60
  61 /* Code that should be executed when program exit, which won't ever
  62  * happen to Manes
  63  */
  64 void *__dso_handle __attribute__((weak));
  65 extern "C" void __cxa_atexit(void (*)(void *), void *, void *) {
  66         /* manes::error er("runtime: attempt to terminate kernel process");
  67         er.critical(); */
  68 }
  69
  70 namespace __cxxabiv1 {
  71         /* Function shows error message when a call to pure virtual function
  72          * has happened */
  73         extern "C" void __cxa_pure_virtual(void) {
  74                 manes::error er("runtime: call to pure virtual function");
  75                 er.critical();
  76         }
  77 }
  78