diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index c0422e2e4..4eca71f1c 100644
--- a/vvp/vthread.cc
+++ b/vvp/vthread.cc
@@ -123,7 +123,7 @@ struct vthread_s {
 static inline void thr_check_addr(struct vthread_s*thr, unsigned addr)
 {
       if (thr->bits4.size() <= addr)
-	    thr->bits4.resize(addr + CPU_WORD_BITS);
+	    thr->bits4.resize(addr+1);
 }
 
 static inline vvp_bit4_t thr_get_bit(struct vthread_s*thr, unsigned addr)
@@ -2673,8 +2673,8 @@ static bool of_MOV_(vthread_t thr, vvp_code_t cp)
 	   neither the source nor the destination to be <4. Otherwise,
 	   we copy all the bits manually. */
 
-      thr_check_addr(thr, cp->bit_idx[0]+cp->number);
-      thr_check_addr(thr, cp->bit_idx[1]+cp->number);
+      thr_check_addr(thr, cp->bit_idx[0]+cp->number-1);
+      thr_check_addr(thr, cp->bit_idx[1]+cp->number-1);
 	// Read the source vector out
       vvp_vector4_t tmp (thr->bits4, cp->bit_idx[1], cp->number);
 	// Write it in the new place.
@@ -2717,7 +2717,7 @@ bool of_MOVI(vthread_t thr, vvp_code_t cp)
       unsigned val = cp->bit_idx[1];
       unsigned wid = cp->number;
 
-      thr_check_addr(thr, dst+wid);
+      thr_check_addr(thr, dst+wid-1);
 
       for (unsigned idx = 0 ;  idx < wid ;  idx += 1, val >>= 1)
 	    thr->bits4.set_bit(dst+idx, (val&1)? BIT4_1 : BIT4_0);
diff --git a/vvp/vvp_net.cc b/vvp/vvp_net.cc
index cd989b1de..788d99c20 100644
--- a/vvp/vvp_net.cc
+++ b/vvp/vvp_net.cc
@@ -526,33 +526,33 @@ void vvp_vector4_t::set_vec(unsigned adr, const vvp_vector4_t&that)
 		  sptr += 1;
 	    }
 
-	    unsigned long hshift = doff+remain;
-	    unsigned long hmask;
-	    if (hshift >= BITS_PER_WORD)
-		  hmask = -1UL;
-	    else
-		  hmask = (1UL << 2UL*(doff+remain)) - 1;
-
-	    unsigned long mask = hmask & ~lmask;
-
-	    bits_ptr_[dptr] =
-		  (bits_ptr_[dptr] & ~mask)
-		  | ((that.bits_ptr_[sptr] << 2UL*doff) & mask);
-
-	    if ((doff + remain) > BITS_PER_WORD) {
-		  unsigned tail = doff + remain - BITS_PER_WORD;
-		  if (tail >= BITS_PER_WORD)
-			mask = -1UL;
+	    if (remain > 0) {
+		  unsigned long hshift = doff+remain;
+		  unsigned long hmask;
+		  if (hshift >= BITS_PER_WORD)
+			hmask = -1UL;
 		  else
-			mask = (1UL << 2UL*tail) - 1;
+			hmask = (1UL << 2UL*(doff+remain)) - 1;
 
-		  dptr += 1;
-		  bits_ptr_[dptr] =
-			(bits_ptr_[dptr] & ~mask)
-			| ((that.bits_ptr_[sptr] >> 2UL*(remain-tail))&mask);
+		  unsigned long mask = hmask & ~lmask;
+
+		  bits_ptr_[dptr] = (bits_ptr_[dptr] & ~mask)
+		        | ((that.bits_ptr_[sptr] << 2UL*doff) & mask);
+
+		  if ((doff + remain) > BITS_PER_WORD) {
+			unsigned tail = doff + remain - BITS_PER_WORD;
+			if (tail >= BITS_PER_WORD)
+			      mask = -1UL;
+			else
+			      mask = (1UL << 2UL*tail) - 1;
+
+			dptr += 1;
+			bits_ptr_[dptr] = (bits_ptr_[dptr] & ~mask) |
+			      ((that.bits_ptr_[sptr] >> 2UL*
+			        (remain-tail))&mask);
+		  }
 	    }
 
-
       }
 }