sw_envs.h

/* File:      sw_envs.h
** Author(s): Terry Swift, Rui Marques, Kostis Sagonas
** Contact:   xsb-contact@cs.sunysb.edu
** 
** Copyright (C) The Research Foundation of SUNY, 1998
** 
** XSB is free software; you can redistribute it and/or modify it under the
** terms of the GNU Library General Public License as published by the Free
** Software Foundation; either version 2 of the License, or (at your option)
** any later version.
** 
** XSB 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 Library General Public License for
** more details.
** 
** You should have received a copy of the GNU Library General Public License
** along with XSB; if not, write to the Free Software Foundation,
** Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** $Id: sw_envs.h,v 1.14 2005/10/03 13:26:43 tswift Exp $
** 
*/

#ifdef PROFILE
#define PROFILE_SWITCH_ENV num_switch_envs++;
#define PROFILE_SWITCH_ENV_ITER num_switch_envs_iter++;
#else
#define PROFILE_SWITCH_ENV 
#define PROFILE_SWITCH_ENV_ITER
#endif

#define freeze_and_switch_envs(tbreg, CPsize)   \
  if (bfreg > breg) {                           \
    CPtr local_top;                             \
    bfreg = breg + CPsize;                      \
    if (trfreg < trreg)  trfreg = trreg;        \
    if (hfreg < hreg)  hfreg = hreg;            \
    local_top = top_of_localstk;                \
    if (efreg > local_top) efreg = local_top;   \
  }                                             \
  switch_envs(tbreg)

/*
 * If PRE_IMAGE_TRAIL is never used, the line of untrail2 in the following
 * macro should be changed to:
 *      untrail((CPtr) trail_variable(start_trreg));
 */
#define switch_envs(tbreg) {                                            \
  CPtr *start_trreg, *end_trreg, *parent, *tmp;                         \
                                                                        \
  PROFILE_SWITCH_ENV                                                    \
  start_trreg = trreg;                                                  \
  end_trreg = trreg = cp_trreg(tbreg);                                  \
  parent = trail_parent(end_trreg);                                     \
  if (start_trreg != end_trreg) {                                       \
    do {                                                                \
      while (start_trreg > end_trreg) {                                 \
        PROFILE_SWITCH_ENV_ITER                                         \
        untrail2(start_trreg, (Cell) trail_variable(start_trreg));      \
        start_trreg = trail_parent(start_trreg);                        \
      }                                                                 \
      while (end_trreg > start_trreg) {                                 \
        PROFILE_SWITCH_ENV_ITER                                         \
        tmp = parent;                                                   \
        parent = trail_parent(parent);                                  \
        *tmp = (CPtr) end_trreg;                                        \
        end_trreg = tmp;                                                \
      }                                                                 \
    } while (start_trreg != end_trreg);                                 \
    tmp = trail_parent(end_trreg);                                      \
    *end_trreg = (CPtr) parent;                                         \
    parent = tmp;                                                       \
    while (end_trreg < trreg) {                                         \
      PROFILE_SWITCH_ENV_ITER                                         \
      tmp = parent;                                                     \
      cell((CPtr)((Cell)trail_variable(tmp) & ~PRE_IMAGE_MARK)) =       \
        (Cell) trail_value(tmp);                                        \
      parent = trail_parent(parent);                                    \
      *tmp = (CPtr) end_trreg;                                          \
      end_trreg = tmp;                                                  \
    }                                                                   \
  }                                                                     \
}

#define undo_bindings(TBREG) {                  \
   CPtr *old_trreg = cp_trreg(TBREG);           \
   table_undo_bindings(old_trreg);              \
}

/*
 * If PRE_IMAGE_TRAIL is never used, the line of untrail2 in the following
 * macro should be changed to:
 *      untrail((CPtr) trail_variable(trreg));
 */
#define table_undo_bindings(old_trreg) {                \
  while (trreg > (CPtr *) old_trreg) {                  \
    untrail2(trreg, (Cell) trail_variable(trreg));      \
    trreg = trail_parent(trreg);                        \
  }                                                     \
}

---