mes/lib/linux/arm-mes-mescc/crt1.c
Danny Milosavljevic d42f99e6cf
mescc: Mes C Library: Hang at the end if necessary.
* lib/linux/arm-mes-mescc/crt1.c (_start): Hang at the end if necessary.
2020-06-10 13:14:33 +02:00

78 lines
2 KiB
C

/* -*-comment-start: "//";comment-end:""-*-
* GNU Mes --- Maxwell Equations of Software
* Copyright © 2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
* Copyright © 2020 Danny Milosavljevic <dannym@scratchpost.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/>.
*/
#include "mes/lib-mini.h"
int main (int argc, char *argv[], char *envp[]);
void /* must not return */
_start ()
{
/*
sp+1 argv UNROLLED ON STACK
sp -> argc
environ = &argv[argc + 1]
HOWEVER, the function entry already allocated space for locals on the stack (after saving lr and fp, which moved sp again). Hence, use fp instead of sp.
*/
/* stdin = 0 */
asm ("!0 mov____$i8,%r0");
asm ("mov____%r0,0x32 &__stdin");
/* stdout = 1 */
asm ("!1 mov____$i8,%r0");
asm ("mov____%r0,0x32 &__stdout");
/* stderr = 2 */
asm ("!2 mov____$i8,%r0");
asm ("mov____%r0,0x32 &__stderr");
/* Add "environ" to main's arguments */
asm ("!8 ldr____%r0,(%fp,+#$i8)"); /* "argc" */
asm ("mov____%fp,%r1");
asm ("!12 add____%r1,$i8"); /* argv */
asm ("add____%r2,%r1,%r0,lsl#2"); /* "environ": argv + argc */
asm ("!4 add____%r2,$i8"); /* "environ": argv + argc + 1 */
asm ("push___%r2"); /* environ */
asm ("push___%r1"); /* argv */
asm ("push___%r0"); /* argc */
/* environ = r2 */
asm ("mov____%r2,0x32 &environ");
main ();
asm ("SYS_exit mov____$i8,%r7");
asm ("swi____$0");
do {
asm ("wfi");
} while (1);
}