diff --git a/C/absmi.c b/C/absmi.c
index 3f6219945..ff3f43d4e 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -3215,6 +3215,35 @@ Yap_absmi(int inp)
       ENDD(d0);
       ENDOp();
 
+      Op(get_yy_var, yyxx);
+      CACHE_Y(YREG);
+      BEGD(d0);
+      BEGP(pt0);
+      pt0 = S_YREG + PREG->u.yyxx.y1;
+      d0 = XREG(PREG->u.yyxx.x1);
+      BEGD(d1);
+      BEGP(pt1);
+      pt1 = S_YREG + PREG->u.yyx.y2;
+      d1 = XREG(PREG->u.yyxx.x2);
+      PREG = NEXTOP(PREG, yyxx);
+#if defined(SBA) && defined(FROZEN_STACKS)
+      Bind_Local(pt0,d0);
+#else
+      *pt0 = d0;
+#endif /* SBA && FROZEN_STACKS */
+#if defined(SBA) && defined(FROZEN_STACKS)
+      Bind_Local(pt1,d1);
+#else
+      *pt1 = d1;
+#endif /* SBA && FROZEN_STACKS */
+      ENDP(pt1);
+      ENDD(d1);
+      GONext();
+      ENDP(pt0);
+      ENDD(d0);
+      ENDCACHE_Y();
+      ENDOp();
+
       /* The code for get_x_val is hard to follow because I use a
        * lot of jumps. The convention is that in the label
        * gval_X_YREG X refers to the state of the first argument, and
@@ -3241,12 +3270,10 @@ Yap_absmi(int inp)
       /* deref second argument */
       deref_body(d1, pt0, gvalx_nonvar_unk, gvalx_nonvar_nonvar);
       /* first argument bound, second unbound */
-      PREG = NEXTOP(PREG, xx);
-      BIND(pt0, d0, bind_gvalx_nonvar_var);
+      BIND_AND_JUMP(pt0, d0);
 #ifdef COROUTINING
       DO_TRAIL(pt0, d0);
       if (pt0 < H0) Yap_WakeUp(pt0);
-    bind_gvalx_nonvar_var:
 #endif
       GONext();
 
@@ -6713,6 +6740,32 @@ Yap_absmi(int inp)
       GONext();
       ENDOp();
 
+      Op(put_y_vals, yyxx);
+      ALWAYS_START_PREFETCH(yyxx);
+      BEGD(d0);
+      d0 = YREG[PREG->u.yyxx.y1];
+#ifdef SBA
+      if (d0 == 0) /* new variable */
+	XREG(PREG->u.yyxx.x1) = (CELL)(YREG+PREG->u.yyxx.y1);
+      else
+#endif
+	XREG(PREG->u.yyxx.x1) = d0;
+      ENDD(d0);
+      /* allow for some prefetching */
+      PREG = NEXTOP(PREG, yyxx);
+      BEGD(d1);
+      d1 = YREG[PREVOP(PREG,yyxx)->u.yyxx.y2];
+#ifdef SBA
+      if (d1 == 0) /* new variable */
+	XREG(PREVOP(PREG->u.yyxx,yyxx).x2) = (CELL)(YREG+PREG->u.yyxx.y2);
+      else
+#endif
+	XREG(PREVOP(PREG,yyxx)->u.yyxx.x2) = d1;
+      ENDD(d1);
+      ALWAYS_END_PREFETCH();
+      GONext();
+      ENDOp();
+
       Op(put_unsafe, yx);
       BEGD(d0);
       BEGP(pt0);
diff --git a/C/amasm.c b/C/amasm.c
index 239277a6b..34a11e113 100644
--- a/C/amasm.c
+++ b/C/amasm.c
@@ -854,13 +854,56 @@ a_vr(op_numbers opcodex, op_numbers opcodey, yamop *code_p, int pass_no, struct
   int is_y_var = (ve->KindOfVE == PermVar);
 
   if (is_y_var) {
-    if (pass_no) {
-      OPREG var_offset;
+      if (opcodey == _put_y_val) {
+	struct PSEUDO *ncpc = cpc->nextInst;
+	if (ncpc->op == put_val_op &&
+	    ((Ventry *) ncpc->rnd1)->KindOfVE == PermVar ) {
+	  /* peephole! two put_y_vars in a row */
+	  if (pass_no) {
+	    OPREG var_offset;
+	    OPREG var_offset2;
+	    Ventry *ve2 = (Ventry *) ncpc->rnd1;
 
-      var_offset = Var_Ref(ve, is_y_var);
-      code_p->opc = emit_op(opcodey);
-      code_p->u.yx.y = emit_yreg(var_offset);
-      code_p->u.yx.x = emit_x(cpc->rnd2);
+	    var_offset = Var_Ref(ve, is_y_var);
+	    code_p->opc = emit_op(_put_y_vals);
+	    code_p->u.yyxx.y1 = emit_yreg(var_offset);
+	    code_p->u.yyxx.x1 = emit_x(cpc->rnd2);
+	    var_offset2 = Var_Ref(ve2, is_y_var);
+	    code_p->u.yyxx.y2 = emit_yreg(var_offset2);
+	    code_p->u.yyxx.x2 = emit_x(ncpc->rnd2);
+	  }
+	  cip->cpc = ncpc;
+	  GONEXT(yyxx);
+	}
+      }
+      if (opcodey == _get_y_var) {
+	struct PSEUDO *ncpc = cpc->nextInst;
+	if (ncpc->op == get_var_op &&
+	    ((Ventry *) ncpc->rnd1)->KindOfVE == PermVar ) {
+	  /* peephole! two put_y_vars in a row */
+	  if (pass_no) {
+	    OPREG var_offset;
+	    OPREG var_offset2;
+	    Ventry *ve2 = (Ventry *) ncpc->rnd1;
+
+	    var_offset = Var_Ref(ve, is_y_var);
+	    code_p->opc = emit_op(_get_yy_var);
+	    code_p->u.yyxx.y1 = emit_yreg(var_offset);
+	    code_p->u.yyxx.x1 = emit_x(cpc->rnd2);
+	    var_offset2 = Var_Ref(ve2, is_y_var);
+	    code_p->u.yyxx.y2 = emit_yreg(var_offset2);
+	    code_p->u.yyxx.x2 = emit_x(ncpc->rnd2);
+	  }
+	  cip->cpc = ncpc;
+	  GONEXT(yyxx);
+	}
+      }
+      if (pass_no) {
+	OPREG var_offset;
+	var_offset = Var_Ref(ve, is_y_var);
+	code_p->opc = emit_op(opcodey);
+	code_p->u.yx.y = emit_yreg(var_offset);
+	code_p->u.yx.x = emit_x(cpc->rnd2);
     }
     GONEXT(yx);
   }
@@ -892,6 +935,12 @@ a_vr(op_numbers opcodex, op_numbers opcodey, yamop *code_p, int pass_no, struct
       code_p->opc = emit_op(opcodex);
       code_p->u.xx.xl = emit_xreg(var_offset);
       code_p->u.xx.xr = emit_x(cpc->rnd2);
+      /* a small trick, usualy the lower argument is the one bound */
+      if (opcodex == _get_x_val && code_p->u.xx.xl > code_p->u.xx.xr) {
+	wamreg x1 = code_p->u.xx.xl;
+	code_p->u.xx.xl = code_p->u.xx.xr;
+	code_p->u.xx.xr = x1;
+      }
     }
     GONEXT(xx);
   }
diff --git a/H/YapOpcodes.h b/H/YapOpcodes.h
index e974144fa..fc3de9981 100644
--- a/H/YapOpcodes.h
+++ b/H/YapOpcodes.h
@@ -55,6 +55,7 @@
 #endif
   OPCODE(get_x_var                  ,xx),
   OPCODE(get_y_var                  ,yx),
+  OPCODE(get_yy_var                 ,yyxx),
   OPCODE(get_x_val                  ,xx),
   OPCODE(get_y_val                  ,yx),
   OPCODE(get_atom                   ,xc),
@@ -142,6 +143,7 @@
   OPCODE(put_x_val                  ,xx),
   OPCODE(put_xx_val                 ,xxxx),
   OPCODE(put_y_val                  ,yx),
+  OPCODE(put_y_vals                 ,yyxx),
   OPCODE(put_unsafe                 ,yx),
   OPCODE(put_atom                   ,xc),
   OPCODE(put_float                  ,xd),
diff --git a/H/absmi.h b/H/absmi.h
index 712ef8733..24b1804fb 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -733,19 +733,17 @@ Macros to check the limits of stacks
 #endif
 
 #define store_yaam_regs(AP,I) \
-                 { register yamop *x1 = (yamop *)(AP);           \
-                   register CELL *x2 = ENV;			 \
-                   /* Jump to CP_BASE */                         \
+                 { /* Jump to CP_BASE */                         \
                    S_YREG = (CELL *)((choiceptr)((S_YREG)-(I))-1);     \
                    /* Save Information */                        \
 		   HBREG = H;                                    \
                    B_YREG->cp_tr = TR;				 \
                    B_YREG->cp_h  = H;				 \
                    B_YREG->cp_b  = B;				 \
-                   store_yaam_reg_cpdepth(B_YREG);                  \
-                   B_YREG->cp_cp = CPREG;				 \
-                   B_YREG->cp_ap = x1;				 \
-                   B_YREG->cp_env= x2;				 \
+                   store_yaam_reg_cpdepth(B_YREG);               \
+                   B_YREG->cp_cp = CPREG;			 \
+                   B_YREG->cp_ap = AP;				 \
+                   B_YREG->cp_env= ENV;				 \
                  }
 
 #define store_yaam_regs_for_either(AP,d0) \
diff --git a/H/amidefs.h b/H/amidefs.h
index 5d8640ae7..74dc862ed 100644
--- a/H/amidefs.h
+++ b/H/amidefs.h
@@ -744,6 +744,13 @@ typedef struct yami {
       wamreg                x;
       CELL next;
     } yyx;
+    struct {
+      yslot                y1;
+      yslot                y2;
+      wamreg               x1;
+      wamreg               x2;
+      CELL next;
+    } yyxx;
     struct {
       yslot                y;
       yslot                y1;
diff --git a/H/amiops.h b/H/amiops.h
index 9354c6722..433f0c927 100644
--- a/H/amiops.h
+++ b/H/amiops.h
@@ -158,9 +158,17 @@ AlignGlobalForDouble(void)
             ((TERM) < (CELL *)B_FZ))                      \
           goto LAB
 
+#define TrailAndJump(TERM, VAL)                             \
+        if (IN_BETWEEN(HBREG,TERM,B) &&                   \
+            ((TERM) < (CELL *)B_FZ))                      \
+          GONext();
+
 #else
 #define Trail(TERM, VAL, LAB)                             \
           TRAIL(TERM, VAL)
+
+#define Trail(TERM, VAL, LAB)                             \
+          TRAIL_AND_JUMP(TERM, VAL)
 #endif
 
 #else /* BBREG_TRAIL_SCHEME */
@@ -173,9 +181,18 @@ AlignGlobalForDouble(void)
 #define Trail(TERM, VAL, LAB)                             \
         if (IN_BETWEEN(HBREG,TERM,BBREG))                 \
           goto LAB
+
+#define TrailAndJump(TERM, VAL)                             \
+        if (IN_BETWEEN(HBREG,TERM,BBREG))                 \
+          GONext();
+
 #else
 #define Trail(TERM, VAL, LAB)                             \
           TRAIL(TERM, VAL)
+
+#define TrailAndJump(TERM, VAL)                             \
+          TRAIL_AND_JUMP(TERM, VAL)
+
 #endif
 
 #define TRAIL_LOCAL(TERM, VAL)                            \
@@ -224,6 +241,9 @@ AlignGlobalForDouble(void)
 #define TRAIL(A,D)        if (OUTSIDE(HBREG,A,B))             \
 				DO_TRAIL(A,D);
 
+#define TRAIL_AND_JUMP(A,D)        if (!OUTSIDE(HBREG,A,B)) GONext();	\
+				DO_TRAIL(A,D);
+
 #define Trail(A, D, LAB)   TRAIL(A,D)
 
 #define TRAIL_GLOBAL(A,D)	if ((A) < HBREG) DO_TRAIL(A,D);
@@ -241,6 +261,10 @@ AlignGlobalForDouble(void)
                         if (OUTSIDE(HBREG,A,B))                            \
                             TR++
 
+#define TRAIL(A,D)        TrailTerm(TR) = (CELL)(A);                       \
+                        if (!OUTSIDE(HBREG,A,B))                            \
+			  GONext();
+
 #define Trail(A,D,LAB)    TRAIL(A,D)
 
 #define TRAIL_GLOBAL(A,D)	TR[0] = (CELL)(A); if ((A) < HBREG) TR++
@@ -256,6 +280,9 @@ AlignGlobalForDouble(void)
 #define TRAIL(A,D)        if (OUTSIDE(HBREG,A,B))            \
                               DO_TRAIL(A,D)
 
+#define TRAIL_AND_JUMP(A,D)        if (IN_BETWEEN(HBREG,A,B)) GONext();	\
+                              DO_TRAIL(A,D)
+
 #define Trail(A,D,LAB)    TRAIL(A,D)
 
 #define TRAIL_GLOBAL(A,D)	if ((A) < HBREG) DO_TRAIL(A,D)
@@ -276,6 +303,9 @@ AlignGlobalForDouble(void)
 #define Trail(A,D,LAB)    if (IN_BETWEEN(HBREG,A,B))            \
                               goto LAB
 
+#define TrailAndJump(A,D)    if (IN_BETWEEN(HBREG,A,B))            \
+    GONext();
+
 #define TRAIL_GLOBAL(A,D)	if ((A) < HBREG) DO_TRAIL(A,D)
 
 #define Trail_Global(A,D,LAB) if ((A) >= HBREG) goto LAB
@@ -316,6 +346,7 @@ Binding Macros for Multiple Assignment Variables.
 #define Bind_Global(A,D)       TRAIL_GLOBAL(A,D); *(A) = (D)
 #define Bind_and_Trail(A,D)    DO_TRAIL(A,D); *(A) = (D)
 #define BIND(A,D,L)            *(A) = (D); Trail(A,D,L)
+#define BIND_AND_JUMP(A,D)     *(A) = (D); TrailAndJump(A,D)
 #define BIND_GLOBAL(A,D,L)     *(A) = (D); Trail_Global(A,D,L)
 
 #ifdef COROUTINING
diff --git a/H/findclause.h b/H/findclause.h
index 6418e4525..8569cd6ab 100644
--- a/H/findclause.h
+++ b/H/findclause.h
@@ -1559,6 +1559,17 @@
       }
       cl = NEXTOP(cl,yyx);
       break;
+    case _get_yy_var:
+      if (!(nofregs = add_regcopy(myregs, nofregs, cl->u.yyxx.x1, cl->u.yyxx.y1))) {
+	clause->Tag = (CELL)NULL;
+	return;
+      }
+      if (!(nofregs = add_regcopy(myregs, nofregs, cl->u.yyxx.x2, cl->u.yyxx.y2))) {
+	clause->Tag = (CELL)NULL;
+	return;
+      }
+      cl = NEXTOP(cl,yyxx);
+      break;
 #ifdef YAPOR
 #endif
 #ifdef TABLING
diff --git a/H/headclause.h b/H/headclause.h
index ce546b843..c15edab75 100644
--- a/H/headclause.h
+++ b/H/headclause.h
@@ -642,6 +642,17 @@
       }
       cl = NEXTOP(cl,yx);
       break;
+    case _get_yy_var:
+      if (cl->u.yyxx.x1 == iarg) {
+	clause->Tag = (CELL)NULL;
+	return;
+      }
+      if (cl->u.yyxx.x2 == iarg) {
+	clause->Tag = (CELL)NULL;
+	return;
+      }
+      cl = NEXTOP(cl,yyxx);
+      break;
 #ifdef YAPOR
 #endif
 #ifdef TABLING
diff --git a/H/rclause.h b/H/rclause.h
index 1b34cbd33..cbb80fa9a 100644
--- a/H/rclause.h
+++ b/H/rclause.h
@@ -856,6 +856,15 @@ restore_opcodes(yamop *pc)
       pc->u.yyx.x = XAdjust(pc->u.yyx.x);
       pc = NEXTOP(pc,yyx);
       break;
+      /* instructions type yyxx */
+    case _get_yy_var:
+    case _put_y_vals:
+      pc->u.yyxx.y1 = YAdjust(pc->u.yyxx.y1);
+      pc->u.yyxx.y2 = YAdjust(pc->u.yyxx.y2);
+      pc->u.yyxx.x1 = XAdjust(pc->u.yyxx.x1);
+      pc->u.yyxx.x2 = XAdjust(pc->u.yyxx.x2);
+      pc = NEXTOP(pc,yyxx);
+      break;
 #ifdef YAPOR
       /* instructions type Otapl */
     case _getwork:
diff --git a/H/walkclause.h b/H/walkclause.h
index 4ed3fd950..6986e43b3 100644
--- a/H/walkclause.h
+++ b/H/walkclause.h
@@ -655,6 +655,11 @@
     case _p_func2f_yy:
       pc = NEXTOP(pc,yyx);
       break;
+      /* instructions type yyxx */
+    case _get_yy_var:
+    case _put_y_vals:
+      pc = NEXTOP(pc,yyxx);
+      break;
 #ifdef YAPOR
       /* instructions type Otapl */
     case _getwork:
diff --git a/misc/buildops b/misc/buildops
index a61942b1d..e92c8191f 100644
--- a/misc/buildops
+++ b/misc/buildops
@@ -790,6 +790,7 @@ opinfo("write_y_val",[body]).
 opinfo("write_y_loc",[body]).
 opinfo("get_x_var",[dup("xr","xl")]).
 opinfo("get_y_var",[dup("x","y")]).
+opinfo("get_yy_var",[dup("x1","y1"),dup("x2","y2")]).
 opinfo("put_x_var",[new("xl"),new("xr")]).
 opinfo("put_y_var",[new("x"),new("y")]).
 opinfo("get_x_val",[unify("xl","xr")]).