mes/lib/linux/crt0.c
Jan Nieuwenhuizen 72cb975213
GNU Mes.
Throughout, make these changes

   Copyright headers: GNU Mes
   First mention of name: GNU Mes
   Website: https://www.gnu.org/software/mes
   Git:     git://git.savannah.gnu.org/mes.git
2018-07-22 14:24:36 +02:00

98 lines
2.3 KiB
C

/* -*-comment-start: "//";comment-end:""-*-
* GNU Mes --- Maxwell Equations of Software
* Copyright © 2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of GNU Mes.
*
* GNU Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* GNU Mes 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
*/
// no clue what crt0.o is and why gcc-2.6.3 needs it
// instead of calling main, it seems to call either _main or ___main,
// let's try _main first
char **environ = 0;
int _main (int argc, char *argv[]);
#if __GNUC__
void
_start ()
{
asm (
"mov %%ebp,%%eax\n\t"
"addl $4,%%eax\n\t"
"movzbl (%%eax),%%eax\n\t"
"addl $3,%%eax\n\t"
"shl $2,%%eax\n\t"
"add %%ebp,%%eax\n\t"
"movl %%eax,%0\n\t"
: "=environ" (environ)
: //no inputs ""
);
asm (
"mov %%ebp,%%eax\n\t"
"addl $8,%%eax\n\t"
"push %%eax\n\t"
"mov %%ebp,%%eax\n\t"
"addl $4,%%eax\n\t"
"movzbl (%%eax),%%eax\n\t"
"push %%eax\n\t"
"call _main\n\t"
"mov %%eax,%%ebx\n\t"
"mov $1,%%eax\n\t"
"int $0x80\n\t"
"hlt \n\t"
:
);
}
#elif __MESC__
int
_start ()
{
asm ("mov____%ebp,%eax");
asm ("add____$i8,%eax !4");
asm ("movzbl_(%eax),%eax");
asm ("add____$i8,%eax !3");
asm ("shl____$i8,%eax !0x02");
asm ("add____%ebp,%eax");
asm ("mov____%eax,0x32 &environ");
asm ("mov____%ebp,%eax");
asm ("add____$i8,%eax !8");
asm ("push___%eax");
asm ("mov____%ebp,%eax");
asm ("add____$i8,%eax !4");
asm ("movzbl_(%eax),%eax");
asm ("push___%eax");
_main ();
asm ("mov____%eax,%ebx");
asm ("mov____$i32,%eax %1");
asm ("int____$0x80");
asm ("hlt");
}
#endif