diff --git a/C/unifyi.c b/C/unifyi.c
deleted file mode 100644
index da43ad335..000000000
--- a/C/unifyi.c
+++ /dev/null
@@ -1,352 +0,0 @@
-/*************************************************************************
-*									 *
-*	 YAP Prolog 							 *
-*									 *
-*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
-*									 *
-* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
-*									 *
-**************************************************************************
-*									 *
-* File:		unify.c							 *
-* Last rev:								 *
-* mods:									 *
-* comments:	Unification and other auxiliary routines for absmi       *
-*									 *
-*************************************************************************/
-
-int 
-IUnify_complex(register CELL *pt0, register CELL *pt0_end,
-	       register CELL *pt1
-)
-{
-#if SHADOW_REGS
-#if defined(B) || defined(TR)
-  register REGSTORE *regp = &REGS;
-
-#define REGS (*regp)
-#endif /* defined(B) || defined(TR) || defined(HB) */
-#endif
-
-#if SHADOW_HB
-  register CELL *HBREG = HB;
-#endif /* SHADOW_HB */
-
-  CELL  **to_visit  = (CELL **)H;
-
-loop:
-  while (pt0 < pt0_end) {
-    register CELL *ptd0 = pt0+1; 
-    register CELL d0;
-
-    ++pt1;
-    pt0 = ptd0;
-    d0 = *ptd0;
-    deref_head(d0, unify_comp_unk);
-  unify_comp_nvar:
-    {
-      register CELL *ptd1 = pt1;
-      register CELL d1 = *ptd1;
-
-      deref_head(d1, unify_comp_nvar_unk);
-    unify_comp_nvar_nvar:
-      if (d0 == d1)
-	continue;
-      if (IsPairTerm(d0)) {
-	if (!IsPairTerm(d1)) {
-	  goto cufail;
-	}
-#ifdef RATIONAL_TREES
-	/* now link the two structures so that no one else will */
-	/* come here */
-	if (pt0 < pt1) {
-	  to_visit[0] = pt0;
-	  to_visit[1] = pt0_end;
-	  to_visit[2] = pt1;
-	  to_visit[3] = (CELL *)d0;
-	  to_visit += 4;
-	  *pt0 = d1;
-	}
-	else {
-	  to_visit[0] = pt1;
-	  to_visit[1] = pt1+(pt0_end-pt0);
-	  to_visit[2] = pt0;
-	  to_visit[3] = (CELL *)d1;
-	  to_visit += 4;
-	  *pt1 = d0;
-	}
-#else
-	/* store the terms to visit */
-	if (pt0 < pt0_end) {
-	  to_visit[0] = pt0;
-	  to_visit[1] = pt0_end;
-	  to_visit[2] = pt1;
-	  to_visit += 3;
-	}
-
-#endif
-	pt0_end = (pt0 = RepPair(d0) - 1) + 2;
-	pt1 = RepPair(d1) - 1;
-	continue;
-      }
-      if (IsApplTerm(d0)) {
-	register Functor f;
-	register CELL *ap2, *ap3;
-
-	if (!IsApplTerm(d1)) {
-	  goto cufail;
-	}
-	/* store the terms to visit */
-	ap2 = RepAppl(d0);
-	ap3 = RepAppl(d1);
-	f = (Functor) (*ap2);
-	/* compare functors */
-	if (f != (Functor) *ap3)
-	  goto cufail;
-	if (IsExtensionFunctor(f)) {
-	  if (unify_extension(f, d0, ap2, d1))
-	    continue;
-	  goto cufail;
-	}
-#ifdef RATIONAL_TREES
-	/* now link the two structures so that no one else will */
-	/* come here */
-	if (pt0 < pt1) {
-	  to_visit[0] = pt0;
-	  to_visit[1] = pt0_end;
-	  to_visit[2] = pt1;
-	  to_visit[3] = (CELL *)d0;
-	  to_visit += 4;
-	  *pt0 = d1;
-	}
-	else {
-	  to_visit[0] = pt1;
-	  to_visit[1] = pt1+(pt0_end-pt0);
-	  to_visit[2] = pt0;
-	  to_visit[3] = (CELL *)d1;
-	  to_visit += 4;
-	  *pt1 = d0;
-	}
-#else
-	/* store the terms to visit */
-	if (pt0 < pt0_end) {
-	  to_visit[0] = pt0;
-	  to_visit[1] = pt0_end;
-	  to_visit[2] = pt1;
-	  to_visit += 3;
-	}
-#endif
-	d0 = ArityOfFunctor(f);
-	pt0 = ap2;
-	pt0_end = ap2 + d0;
-	pt1 = ap3;
-	continue;
-      }
-      goto cufail;
-
-      derefa_body(d1, ptd1, unify_comp_nvar_unk, unify_comp_nvar_nvar);
-	/* d1 and pt2 have the unbound value, whereas d0 is bound */
-      Bind_Global(ptd1, d0, bind_unify1);
-#ifdef COROUTINING
-      DO_TRAIL(ptd1, d0);
-      if (ptd1 < H0) WakeUp(ptd1);
-    bind_unify1:
-#endif
-      continue;
-    }
-
-    derefa_body(d0, ptd0, unify_comp_unk, unify_comp_nvar);
-    {
-      register CELL d1;
-      register CELL *ptd1;
-
-      d1 = pt1[0];
-      /* pt2 is unbound */
-      ptd1 = pt1;
-      deref_head(d1, unify_comp_var_unk);
-    unify_comp_var_nvar:
-      /* pt2 is unbound and d1 is bound */
-      Bind_Global(ptd0, d1, bind_unify2);
-#ifdef COROUTINING
-      DO_TRAIL(ptd0, d1);
-      if (ptd0 < H0) WakeUp(ptd0);
-    bind_unify2:
-#endif
-      continue;
-
-      {
-
-	derefa_body(d1, ptd1, unify_comp_var_unk, unify_comp_var_nvar);
-	/* ptd0 and ptd1 are unbound */
-	UnifyGlobalCells(ptd0, ptd1, ugc1, ugc2);
-#ifdef COROUTINING
-	DO_TRAIL(ptd0, (CELL)ptd1);
-	if (ptd0 < H0) WakeUp(ptd0);
-      ugc1:
-#endif
-	continue;
-#ifdef COROUTINING
-      ugc2:
-	DO_TRAIL(ptd1, (CELL)ptd0);
-	if (ptd1 < H0) WakeUp(ptd1);
-	continue;
-#endif
-      }
-    }
-  }
-  /* Do we still have compound terms to visit */
-  if (to_visit > (CELL **) H) {
-#ifdef RATIONAL_TREES
-    to_visit -= 4;
-    pt0 = to_visit[0];
-    pt0_end = to_visit[1];
-    pt1 = to_visit[2];
-    *pt0 = (CELL)to_visit[3];
-#else
-    to_visit -= 3;
-    pt0 = to_visit[0];
-    pt0_end = to_visit[1];
-    pt1 = to_visit[2];
-#endif
-    goto loop;
-  }
-  return (TRUE);
-
-cufail:
-#ifdef RATIONAL_TREES
-  /* failure */
-  while (to_visit > (CELL **) H) {
-    CELL *pt0;
-    to_visit -= 4;
-    pt0 = to_visit[0];
-    *pt0 = (CELL)to_visit[3];
-  }
-#endif
-  return (FALSE);
-#if SHADOW_REGS
-#if defined(B) || defined(TR)
-#undef REGS
-#endif /* defined(B) || defined(TR) */
-#endif
-}
-
-int 
-IUnify(register CELL d0, register CELL d1)
-{
-#if SHADOW_REGS
-#if defined(B) || defined(TR)
-  register REGSTORE *regp = &REGS;
-
-#define REGS (*regp)
-#endif /* defined(B) || defined(TR) */
-#endif
-
-#if SHADOW_HB
-  register CELL *HBREG = HB;
-#endif
-
-  register CELL *pt0, *pt1;
-
-  deref_head(d0, unify_unk);
-
-unify_nvar:
-  /* d0 is bound */
-  deref_head(d1, unify_nvar_unk);
-unify_nvar_nvar:
-  /* both arguments are bound */
-  if (d0 == d1)
-    return (TRUE);
-  if (IsPairTerm(d0)) {
-    if (!IsPairTerm(d1)) {
-      return (FALSE);
-    }
-    pt0 = RepPair(d0);
-    pt1 = RepPair(d1);
-    return (IUnify_complex(pt0 - 1, pt0 + 1, pt1 - 1));
-  }
-  else if (IsApplTerm(d0)) {
-    pt0 = RepAppl(d0);
-    d0 = *pt0;
-    if (!IsApplTerm(d1))
-      return (FALSE);      
-    pt1 = RepAppl(d1);
-    d1 = *pt1;
-    if (d0 != d1) {
-      return (FALSE);
-    } else {
-      if (IsExtensionFunctor((Functor)d0)) {
-	switch(d0) {
-	case (CELL)FunctorDBRef:
-	  return(pt0 == pt1);
-	case (CELL)FunctorLongInt:
-	  return(pt0[1] == pt1[1]);
-	case (CELL)FunctorDouble:
-	  return(FloatOfTerm(AbsAppl(pt0)) == FloatOfTerm(AbsAppl(pt1)));
-#ifdef USE_GMP
-	case (CELL)FunctorBigInt:
-	  return(mpz_cmp(BigIntOfTerm(AbsAppl(pt0)),BigIntOfTerm(AbsAppl(pt0))) == 0);
-#endif /* USE_GMP */
-	default:
-	  return(FALSE);
-	}
-      }
-      return (IUnify_complex(pt0, pt0 + ArityOfFunctor((Functor) d0),
-			     pt1));
-    }
-  } else {
-    return (FALSE);
-  }
-
-  deref_body(d1, pt1, unify_nvar_unk, unify_nvar_nvar);
-  /* d0 is bound and d1 is unbound */
-  Bind(pt1, d0, bind_unify3);
-#ifdef COROUTINING
-  DO_TRAIL(pt1, d0);
-  if (pt1 < H0) WakeUp(pt1);
- bind_unify3:
-#endif
-  return (TRUE);
-
-  deref_body(d0, pt0, unify_unk, unify_nvar);
-  /* pt0 is unbound */
-  deref_head(d1, unify_var_unk);
-unify_var_nvar:
-  /* pt0 is unbound and d1 is bound */
-  Bind(pt0, d1, bind_unify4);
-#ifdef COROUTINING
-  DO_TRAIL(pt0, d1);
-  if (pt0 < H0) WakeUp(pt0);
- bind_unify4:
-#endif
-  return (TRUE);
-
-#if TRAILING_REQUIRES_BRANCH
-unify_var_nvar_trail:
-  DO_TRAIL(pt0);
-  return (TRUE);
-#endif
-
-  deref_body(d1, pt1, unify_var_unk, unify_var_nvar);
-  /* d0 and pt1 are unbound */
-  UnifyCells(pt0, pt1, uc1, uc2);
-#ifdef COROUTINING
-  DO_TRAIL(pt0, (CELL)pt1);
-  if (pt0 < H0) WakeUp(pt0);
- uc1:
-#endif
-  return (TRUE);
-#ifdef COROUTINING
- uc2:
-  DO_TRAIL(pt1, (CELL)pt0);
-  if (pt1 < H0) {
-    WakeUp(pt1);
-  }
-  return (TRUE);
-#endif
-#if SHADOW_REGS
-#if defined(B) || defined(TR)
-#undef REGS
-#endif /* defined(B) || defined(TR) */
-#endif
-}
-