Tags_32LowTag.h

/*************************************************************************
*                                    *
*    YAP Prolog     %W% %G%                      *
*   Yap Prolog was developed at NCCUP - Universidade do Porto    *
*                                    *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997   *
*                                    *
**************************************************************************
*                                    *
* File:     Tags_32LowTag.h.m4                   *
* Last rev: December 90                      *
* mods:                                  *
* comments: Original Tag Scheme for machines with 32 bits adresses   *
* version:      $Id: Tags_32LowTag.h,v 1.4 2008-01-30 10:35:43 vsc Exp $     *
*************************************************************************/
 
#if SIZEOF_INT_P==4 && USE_LOW32_TAGS
 
#define TAG_LOW_BITS_32 1
 
     /*    Version for 32 bit addresses machines,
        Each    term is represented internally as an unsigned 32 bit integer as
        follows:
        tag      value
        ints            m.....110 numeric value
        atoms           m.....010 offset of atom entry
        pairs           mr.....11 ptr to pair
        aplied functor  mr.....01 ptr to functor followed by args
        ref             mr.....00 address of cell
        undefined       mr.....00 address of cell pointing to itself
 
        functors are represented as ptrs to the functor entry in the atom
        property list
 
      */
 
#define SHIFT_LOW_TAG 2
#define SHIFT_HIGH_TAG 2
 
#define MKTAG(HI,LO)   ((((UInt) (HI))<<SHIFT_HIGH_TAG)|(LO))
 
#define TagBits     /* 0x00000007L */ MKTAG(0x1,3)
#define LowTagBits  /* 0x00000003L */ MKTAG(0x0,3)
#define LowBit      /* 0x00000001L */ MKTAG(0x0,1)
#define HighTagBits /* 0x0000000cL */ MKTAG(0x1,0)
#define NumberTag   /* 0x0000000dL */ MKTAG(0x1,2)
#define AtomTag     /* 0x00000006L */ MKTAG(0x0,2)
 
/*
    subtract the total for tag bits, plus 1 bit for GC, plus another
    for sign
*/
#define MAX_ABS_INT ((Int)0x04000000L)
 
/*
    UNIQUE_TAG_FOR_PAIR gives the representation for pair an
        unique tag
 
    This allows optimisation of switch_list
 
*/
#define UNIQUE_TAG_FOR_PAIRS 1
 
#define PairBits    /* 0x00000003L */ MKTAG(0x0,3)
#define ApplBit     /* 0x00000001L */ MKTAG(0x0,1)
#define PrimiBits   /* 0x00000002L */ MKTAG(0x0,2)
#define NumberBits  /* 0x0000000aL */ MKTAG(0x2,2)
#define NumberMask  /* 0x0000000bL */ MKTAG(0x2,3)
 
#define TagOf(V)    (Unsigned(V) & LowTagBits)
#define LowTagOf(V) (Unsigned(V) & LowTagBits)
#define NonTagPart(V)   ((Unsigned(V)>>1) & ~LowTagBits)
#define TAGGED(TAG,V)   (((Unsigned(V)<<(SHIFT_HIGH_TAG+SHIFT_LOW_TAG+1))>>1)|(TAG))
#define NONTAGGED(TAG,V) ((Unsigned(V)<<(SHIFT_HIGH_TAG+SHIFT_LOW_TAG+1))>>1)
#define TAGGEDA(TAG,V)  ((Unsigned(V) << 1)|(TAG))
#define CHKTAG(t,Tag)   ((Unsigned(t)&TagBits)==Tag)
 
/* bits that should not be used by anyone but us */
#define YAP_PROTECTED_MASK 0xc0000000L
 
#include "inline-only.h"
INLINE_ONLY EXTERN int IsVarTerm (Term);
 
INLINE_ONLY EXTERN int
IsVarTerm (Term t)
{
  return (int) (!((t) & LowTagBits));
}
 
 
 
INLINE_ONLY EXTERN int IsNonVarTerm (Term);
 
INLINE_ONLY EXTERN int
IsNonVarTerm (Term t)
{
  return (int) (((t) & LowTagBits));
}
 
 
 
INLINE_ONLY EXTERN Term *RepPair (Term);
 
INLINE_ONLY EXTERN Term *
RepPair (Term t)
{
  return (Term *) ((t) - PairBits);
}
 
 
 
INLINE_ONLY EXTERN Term AbsPair (Term *);
 
INLINE_ONLY EXTERN Term
AbsPair (Term * p)
{
  return (Term) (Unsigned (p) + PairBits);
}
 
 
 
INLINE_ONLY EXTERN Int IsPairTerm (Term);
 
INLINE_ONLY EXTERN Int
IsPairTerm (Term t)
{
  return (Int) ((((t) & LowTagBits) == PairBits));
}
 
 
 
INLINE_ONLY EXTERN Term *RepAppl (Term);
 
INLINE_ONLY EXTERN Term *
RepAppl (Term t)
{
  return (Term *) (((t) - ApplBit));
}
 
 
 
INLINE_ONLY EXTERN Term AbsAppl (Term *);
 
INLINE_ONLY EXTERN Term
AbsAppl (Term * p)
{
  return (Term) (Unsigned (p) + ApplBit);
}
 
 
 
INLINE_ONLY EXTERN Int IsApplTerm (Term);
 
INLINE_ONLY EXTERN Int
IsApplTerm (Term t)
{
  return (Int) ((((t) & LowTagBits) == ApplBit));
}
 
 
 
INLINE_ONLY EXTERN Int IsAtomOrIntTerm (Term);
 
INLINE_ONLY EXTERN Int
IsAtomOrIntTerm (Term t)
{
  return (Int) ((((t) & LowTagBits) == 2));
}
 
 
 
 
INLINE_ONLY EXTERN Term AdjustPtr (Term t, Term off);
 
INLINE_ONLY EXTERN Term
AdjustPtr (Term t, Term off)
{
  return (Term) ((t) + off);
}
 
 
 
INLINE_ONLY EXTERN Term AdjustIDBPtr (Term t, Term off);
 
INLINE_ONLY EXTERN Term
AdjustIDBPtr (Term t, Term off)
{
  return (Term) ((t) + off);
}
 
 
 
 
INLINE_ONLY EXTERN Int IntOfTerm (Term);
 
INLINE_ONLY EXTERN Int
IntOfTerm (Term t)
{
  return (Int) (((Int) (t << 1)) >> (SHIFT_LOW_TAG + SHIFT_HIGH_TAG + 1));
}
 
#endif