sysdeps/unix/sysv/linux/sparc/sparc64/swapcontext.c

   1 /* Copyright (C) 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Jakub Jelinek <jakub@redhat.com>.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <ucontext.h>
  21
  22 extern int __getcontext (ucontext_t *ucp);
  23 extern int __setcontext (const ucontext_t *ucp, int restoremask);
  24
  25 int
  26 __swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
  27 {
  28   extern void __swapcontext_ret (void);
  29   /* Save the current machine context to oucp.  */
  30   __getcontext (oucp);
  31   /* Modify oucp to skip the __setcontext call on reactivation.  */
  32   oucp->uc_mcontext.mc_gregs[MC_PC] = (long) __swapcontext_ret;
  33   oucp->uc_mcontext.mc_gregs[MC_NPC] = ((long) __swapcontext_ret) + 4;
  34   /* Restore the machine context in ucp.  */
  35   __setcontext (ucp, 1);
  36   return 0;
  37 }
  38
  39 asm ("                                                  \n\
  40         .text                                           \n\
  41         .type   __swapcontext_ret, #function            \n\
  42 __swapcontext_ret:                                      \n\
  43         return  %i7 + 8                                 \n\
  44          clr    %o0                                     \n\
  45         .size   __swapcontext_ret, .-__swapcontext_ret  \n\
  46      ");
  47
  48 weak_alias (__swapcontext, swapcontext)