sysdeps/x86_64/stackinfo.h

   1 /* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 /* This file contains a bit of information about the stack allocation
  20    of the processor.  */
  21
  22 #ifndef _STACKINFO_H
  23 #define _STACKINFO_H    1
  24
  25 /* On x86_64 the stack grows down.  */
  26 #define _STACK_GROWS_DOWN       1
  27
  28 /* Access to the stack pointer.  The macros are used in alloca_account
  29    for which they need to act as barriers as well, hence the additional
  30    (unnecessary) parameters.  */
  31 #define stackinfo_get_sp() \
  32   ({ void *p__; asm volatile ("mov %%rsp, %0" : "=r" (p__)); p__; })
  33 #define stackinfo_sub_sp(ptr) \
  34   ({ ptrdiff_t d__;                                             \
  35      asm volatile ("sub %%rsp, %0" : "=r" (d__) : "0" (ptr));   \
  36      d__; })
  37
  38 #endif  /* stackinfo.h */