diff --git a/tgt-vvp/eval_vec4.c b/tgt-vvp/eval_vec4.c
index b167b664e..193387196 100644
--- a/tgt-vvp/eval_vec4.c
+++ b/tgt-vvp/eval_vec4.c
@@ -1008,7 +1008,8 @@ static void draw_darray_pop(ivl_expr_t expr)
       ivl_expr_t arg = ivl_expr_parm(expr, 0);
       assert(ivl_expr_type(arg) == IVL_EX_SIGNAL);
 
-      fprintf(vvp_out, "    %%qpop/%s/v v%p_0;\n", fb, ivl_expr_signal(arg));
+      fprintf(vvp_out, "    %%qpop/%s/v v%p_0, %u;\n", fb, ivl_expr_signal(arg),
+                       ivl_expr_width(expr));
 }
 
 static void draw_sfunc_vec4(ivl_expr_t expr)
diff --git a/vvp/compile.cc b/vvp/compile.cc
index 4225d0433..441aa26fc 100644
--- a/vvp/compile.cc
+++ b/vvp/compile.cc
@@ -249,10 +249,10 @@ static const struct opcode_table_s opcode_table[] = {
       { "%putc/str/vec4",of_PUTC_STR_VEC4,2,{OA_FUNC_PTR,OA_BIT1,OA_NONE} },
       { "%qpop/b/real",of_QPOP_B_REAL,1,{OA_FUNC_PTR,OA_NONE,OA_NONE} },
       { "%qpop/b/str", of_QPOP_B_STR, 1,{OA_FUNC_PTR,OA_NONE,OA_NONE} },
-      { "%qpop/b/v",   of_QPOP_B_V,   1,{OA_FUNC_PTR,OA_NONE,OA_BIT2} },
+      { "%qpop/b/v",   of_QPOP_B_V,   2,{OA_FUNC_PTR,OA_BIT1,OA_NONE} },
       { "%qpop/f/real",of_QPOP_F_REAL,1,{OA_FUNC_PTR,OA_NONE,OA_NONE} },
       { "%qpop/f/str", of_QPOP_F_STR, 1,{OA_FUNC_PTR,OA_NONE,OA_NONE} },
-      { "%qpop/f/v",   of_QPOP_F_V,   1,{OA_FUNC_PTR,OA_NONE,OA_BIT2} },
+      { "%qpop/f/v",   of_QPOP_F_V,   2,{OA_FUNC_PTR,OA_BIT1,OA_NONE} },
       { "%release/net",of_RELEASE_NET,3,{OA_FUNC_PTR,OA_BIT1,OA_BIT2} },
       { "%release/reg",of_RELEASE_REG,3,{OA_FUNC_PTR,OA_BIT1,OA_BIT2} },
       { "%release/wr", of_RELEASE_WR, 2,{OA_FUNC_PTR,OA_BIT1,OA_NONE} },
diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index 731a25ecd..f518111cb 100644
--- a/vvp/vthread.cc
+++ b/vvp/vthread.cc
@@ -5025,15 +5025,17 @@ bool of_QPOP_B_REAL(vthread_t thr, vvp_code_t cp)
 {
       vvp_net_t*net = cp->net;
 
-      vvp_queue*dqueue = get_queue_object<vvp_queue_string>(thr, net);
+      vvp_queue*dqueue = get_queue_object<vvp_queue_real>(thr, net);
       assert(dqueue);
 
       size_t size = dqueue->get_size();
-      assert(size > 0);
 
       double value;
-      dqueue->get_word(size-1, value);
-      dqueue->pop_back();
+      if (size) {
+	    dqueue->get_word(size-1, value);
+	    dqueue->pop_back();
+      } else
+	    value = 0.0;
 
       thr->push_real(value);
       return true;
@@ -5050,11 +5052,13 @@ bool of_QPOP_B_STR(vthread_t thr, vvp_code_t cp)
       assert(dqueue);
 
       size_t size = dqueue->get_size();
-      assert(size > 0);
 
       string value;
-      dqueue->get_word(size-1, value);
-      dqueue->pop_back();
+      if (size) {
+	    dqueue->get_word(size-1, value);
+	    dqueue->pop_back();
+      } else
+	    value = "";
 
       thr->push_str(value);
       return true;
@@ -5066,17 +5070,21 @@ bool of_QPOP_B_STR(vthread_t thr, vvp_code_t cp)
 bool of_QPOP_B_V(vthread_t thr, vvp_code_t cp)
 {
       vvp_net_t*net = cp->net;
+      unsigned width  = cp->bit_idx[0];
 
       vvp_queue*dqueue = get_queue_object<vvp_queue_vec4>(thr, net);
       assert(dqueue);
 
       size_t size = dqueue->get_size();
-      assert(size > 0);
 
       vvp_vector4_t value;
-      dqueue->get_word(size-1, value);
-      dqueue->pop_back();
+      if (size) {
+	    dqueue->get_word(size-1, value);
+	    dqueue->pop_back();
+      } else
+	    value = vvp_vector4_t(width);
 
+      assert(width == value.size());
       thr->push_vec4(value);
       return true;
 }
@@ -5088,12 +5096,17 @@ bool of_QPOP_F_REAL(vthread_t thr, vvp_code_t cp)
 {
       vvp_net_t*net = cp->net;
 
-      vvp_queue*dqueue = get_queue_object<vvp_queue_string>(thr, net);
+      vvp_queue*dqueue = get_queue_object<vvp_queue_real>(thr, net);
       assert(dqueue);
 
+      size_t size = dqueue->get_size();
+
       double value;
-      dqueue->get_word(0, value);
-      dqueue->pop_front();
+      if (size) {
+	    dqueue->get_word(0, value);
+	    dqueue->pop_front();
+      } else
+	    value = 0.0;
 
       thr->push_real(value);
       return true;
@@ -5109,9 +5122,14 @@ bool of_QPOP_F_STR(vthread_t thr, vvp_code_t cp)
       vvp_queue*dqueue = get_queue_object<vvp_queue_string>(thr, net);
       assert(dqueue);
 
+      size_t size = dqueue->get_size();
+
       string value;
-      dqueue->get_word(0, value);
-      dqueue->pop_front();
+      if (size) {
+	    dqueue->get_word(0, value);
+	    dqueue->pop_front();
+      } else
+	    value = "";
 
       thr->push_str(value);
       return true;
@@ -5123,17 +5141,21 @@ bool of_QPOP_F_STR(vthread_t thr, vvp_code_t cp)
 bool of_QPOP_F_V(vthread_t thr, vvp_code_t cp)
 {
       vvp_net_t*net = cp->net;
+      unsigned width  = cp->bit_idx[0];
 
       vvp_queue*dqueue = get_queue_object<vvp_queue_vec4>(thr, net);
       assert(dqueue);
 
       size_t size = dqueue->get_size();
-      assert(size > 0);
 
       vvp_vector4_t value;
-      dqueue->get_word(0, value);
-      dqueue->pop_front();
+      if (size) {
+	    dqueue->get_word(0, value);
+	    dqueue->pop_front();
+      } else
+	    value = vvp_vector4_t(width);
 
+      assert(width == value.size());
       thr->push_vec4(value);
       return true;
 }