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//////////////////////////////////////////////////////////////////////////////
//Copyright 2008
// Andrew Gacek, Steven Holte, Gopalan Nadathur, Xiaochu Qi, Zach Snow
//////////////////////////////////////////////////////////////////////////////
// This file is part of Teyjus. //
// //
// Teyjus is free software: you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation, either version 3 of the License, or //
// (at your option) any later version. //
// //
// Teyjus 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 General Public License for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with Teyjus. If not, see <http://www.gnu.org/licenses/>. //
//////////////////////////////////////////////////////////////////////////////
/****************************************************************************/
/* */
/* File trail.c. This file defines the trail operations including */
/* trailing and unwinding. */
/* */
/****************************************************************************/
#ifndef TRAIL_C
#define TRAIL_C
#include "trail.h"
static int TR_trailItemTag(TR_TrailItem *trPtr) { return (trPtr -> tag); }
static MemPtr TR_trailItemAddr(TR_TrailItem *trPtr) { return (trPtr -> addr);}
/***************************************************************************/
/* TRAILING FUNCTIONS */
/***************************************************************************/
void TR_trailTerm(DF_TermPtr addr) //trailing a term of atomic size
{
if (((MemPtr)addr <= AM_hbreg) ||
((AM_hreg < (MemPtr)addr) && ((MemPtr)addr < AM_breg))) {
AM_trailError(TR_TRAIL_TERM_SIZE);
DF_copyAtomic(addr, AM_trreg);
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE))->tag = TR_TAG_TERM;
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE))->addr = (MemPtr)addr;
AM_trreg += TR_TRAIL_TERM_SIZE;
}
}
void TR_trailHTerm(DF_TermPtr addr) //trailing a heap term of atomic size
{
if ((MemPtr)addr < AM_hbreg) {
AM_trailError(TR_TRAIL_TERM_SIZE);
DF_copyAtomic(addr, AM_trreg);
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE)) -> tag = TR_TAG_TERM;
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE)) -> addr = (MemPtr)addr;
AM_trreg += TR_TRAIL_TERM_SIZE;
}
}
void TR_trailETerm(DF_TermPtr addr) //trailing a stack term
{
if ((MemPtr)addr < AM_breg) {
AM_trailError(TR_TRAIL_TERM_SIZE);
DF_copyAtomic(addr, AM_trreg);
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE)) -> tag = TR_TAG_TERM;
((TR_TrailItem*)(AM_trreg+DF_TM_ATOMIC_SIZE)) -> addr = (MemPtr)addr;
AM_trreg += TR_TRAIL_TERM_SIZE;
}
}
void TR_trailType(DF_TypePtr addr) //trailing a type (free variable)
{
if (((MemPtr)addr < AM_hbreg) ||
((AM_hreg < (MemPtr)addr) && ((MemPtr)addr < AM_breg))){
AM_trailError(TR_TRAIL_TYPE_SIZE);
((TR_TrailItem*)AM_trreg) -> tag = TR_TAG_TYPE;
((TR_TrailItem*)AM_trreg) -> addr = (MemPtr)addr;
AM_trreg += TR_TRAIL_TYPE_SIZE;
}
}
//temp
void TR_trailImport(MemPtr addr) //trailing a backchained field
{
AM_trailError(TR_TRAIL_MOD_SIZE);
*AM_trreg = *addr;
*(AM_trreg+1) = *(addr+1);
((TR_TrailItem*)(AM_trreg+2)) -> tag = TR_TAG_MOD;
((TR_TrailItem*)(AM_trreg+2)) -> addr = addr;
AM_trreg += TR_TRAIL_MOD_SIZE;
}
/****************************************************************************/
/* UNWIND TRAIL FUNCTION */
/****************************************************************************/
void TR_unwindTrail(MemPtr trOld)
{
MemPtr addr;
while (AM_trreg > trOld){
AM_trreg -= TR_TRAIL_ITEM_HEAD_SIZE;
addr = TR_trailItemAddr((TR_TrailItem*)AM_trreg);
switch (TR_trailItemTag((TR_TrailItem*)AM_trreg)){
case TR_TAG_TERM:
{
AM_trreg -= DF_TM_ATOMIC_SIZE;
DF_copyAtomic((DF_TermPtr)AM_trreg, addr);
break;
}
case TR_TAG_MULTERM1:
{
AM_trreg -= DF_TM_APP_SIZE;
DF_copyApp((DF_TermPtr)AM_trreg, addr);
break;
}
case TR_TAG_MULTERM2:
{
AM_trreg -= DF_TM_SUSP_SIZE;
DF_copySusp((DF_TermPtr)AM_trreg, addr);
break;
}
case TR_TAG_TYPE:
{
DF_mkFreeVarType(addr);
break;
}
case TR_TAG_MOD: //temp
{
AM_trreg -= 2;
*addr = *AM_trreg;
*(addr+1) = *(AM_trreg + 1);
break;
}
} //switch
} //while
}
#endif //TRAIL_C
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