libc/sysdeps/linux/sparc64/makecontext.c

   1 /* Copyright (C) 2001-2017 Free Software Foundation, Inc.
   2    Contributed by Jakub Jelinek <jakub@redhat.com>.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <stdarg.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <ucontext.h>
  22
  23 extern void __start_context (struct ucontext *ucp);
  24
  25 void
  26 __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
  27 {
  28   extern void __makecontext_ret (void);
  29   unsigned long *sp, *topsp;
  30   va_list ap;
  31   int i;
  32
  33   sp = (unsigned long *) ((long) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
  34   sp -= (argc > 6 ? argc : 6) + 32;
  35   sp = (unsigned long *) (((long) sp) & -16L);
  36   topsp = sp + (argc > 6 ? argc : 6) + 16;
  37
  38   ucp->uc_mcontext.mc_gregs[MC_PC] = (long) func;
  39   ucp->uc_mcontext.mc_gregs[MC_NPC] = ((long) func) + 4;
  40   ucp->uc_mcontext.mc_gregs[MC_O6] = ((long) sp) - 0x7ff;
  41   ucp->uc_mcontext.mc_gregs[MC_O7] = ((long) __start_context) - 8;
  42   ucp->uc_mcontext.mc_fp = ((long) topsp) - 0x7ff;
  43   ucp->uc_mcontext.mc_i7 = 0;
  44   topsp[14] = 0;
  45   topsp[15] = 0;
  46   sp[8] = (long) ucp->uc_link;
  47   va_start (ap, argc);
  48   for (i = 0; i < argc; ++i)
  49     if (i < 6)
  50       ucp->uc_mcontext.mc_gregs[MC_O0 + i] = va_arg (ap, long);
  51     else
  52       sp[16 + i] = va_arg (ap, long);
  53   va_end (ap);
  54 }
  55
  56 weak_alias (__makecontext, makecontext)