mes/lib/x86_64-mes-gcc/setjmp.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/>.
 */

#include <setjmp.h>

void
longjmp (jmp_buf env, int val)
{
  val = val == 0 ? 1 : val;
  asm (
       "mov    0x00(%rdi),%rbp\n\t"     // env->__bp
       "mov    0x08(%rdi),%rbx\n\t"     // env->__pc
       "mov    0x10(%rdi),%rsp\n\t"     // env->__sp
       "jmp    *%rbx\n\t"               // jmp *PC
       );
  // not reached
  exit (42);
}

int
setjmp (jmp_buf env)
{
  long *p;
  asm ("mov    %%rbp,%0"
       : "=r" (p)
       : //no inputs ""
       );
  env[0].__bp = p;
  env[0].__pc = p[1];
  env[0].__sp = p[0];
  return 0;
}