mes/libc/mstart.c
Jan Nieuwenhuizen 996c449a81 mescc: Add getenv.
* module/mes/libc-i386.mes (i386:_start): Push environment pointer.
* module/mes/libc.mes (g_environment): New global.
  (_env): New function.
  (_start): Use it to set g_environment.
  (getenv): New function.
* lib/mlibc.c (strncmp): New function.
  (getenv): Implement.
* lib/mstart.c (_start): Set g_environment.
* module/mes/libc.mes (strncmp): New function.
  (libc): Add it.
* scaffold/t.c: (array_ref): Test it.
2017-04-17 02:24:20 +02:00

56 lines
1.5 KiB
C

/* -*-comment-start: "//";comment-end:""-*-
* Mes --- Maxwell Equations of Software
* Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of Mes.
*
* 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.
*
* 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 Mes. If not, see <http://www.gnu.org/licenses/>.
*/
#if __GNUC__
void
_start ()
{
// char **;
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"
: "=g_environment" (g_environment)
: //no inputs ""
);
int r;
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"
"movl %%eax,%0\n\t"
: "=r" (r)
: //no inputs ""
);
exit (r);
}
#endif