sysdeps/unix/sysv/linux/alpha/swapcontext.S

   1 /* Save current context and install the given one.
   2    Copyright (C) 2004-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20 #include <ucontext-offsets.h>
  21
  22 ENTRY(__swapcontext)
  23
  24 #ifdef PROF
  25         ldgp    $29, 0($27)
  26         .set noat
  27         lda     AT, _mcount
  28         jsr     AT, (AT), _mcount
  29         .set at
  30         .prologue 1
  31 #elif defined PIC
  32         .prologue 0
  33 #else
  34         ldgp    $29, 0($27)
  35         .prologue 1
  36 #endif
  37
  38 #ifdef PIC
  39         unop
  40         bsr     $0, __getcontext_x      !samegp
  41         mov     $17, $16
  42         br      $31, __setcontext       !samegp
  43 #else
  44         jsr     $0, __getcontext_x
  45         mov     $17, $16
  46         jmp     $31, __setcontext
  47 #endif
  48
  49 END(__swapcontext)
  50 weak_alias (__swapcontext, swapcontext)