diff --git a/src/rpn-branch.hpp b/src/rpn-branch.hpp
index 2012e49..5b93bfc 100644
--- a/src/rpn-branch.hpp
+++ b/src/rpn-branch.hpp
@@ -89,17 +89,13 @@ void rpn_ift(void)
     if (!mpfr_zero_p(testee->_value.mpfr))
     {
         CHECK_MPFR(stack::copy_and_push_back(*_stack, _stack->size()-1, _calc_stack));
-        (void)_stack->pop_back();
-        (void)_stack->pop_back();
+        (void)_stack->pop_back(2);
 
         CHECK_MPFR(stack::copy_and_push_back(_calc_stack, _calc_stack.size()-1, *_stack));
         (void)_calc_stack.pop_back();
     }
     else
-    {
-        (void)_stack->pop_back();
-        (void)_stack->pop_back();
-    }
+        (void)_stack->pop_back(2);
 }
 
 void rpn_ifte(void)
@@ -116,9 +112,7 @@ void rpn_ifte(void)
     else
         CHECK_MPFR(stack::copy_and_push_back(*_stack, _stack->size()-1, _calc_stack));
 
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
+    (void)_stack->pop_back(3);
 
     CHECK_MPFR(stack::copy_and_push_back(_calc_stack, _calc_stack.size()-1, *_stack));
     (void)_calc_stack.pop_back();
@@ -242,8 +236,7 @@ int rpn_next(branch& myobj)
     {
         // end of loop
         myobj.arg_bool = false;// init again next time
-        _calc_stack.pop_back();
-        _calc_stack.pop_back();
+        _calc_stack.pop_back(2);
         return -1;
     }
     else
@@ -298,8 +291,7 @@ int rpn_step(branch& myobj)
         {
             // end of loop
             myobj.arg_bool = false;// init again next time
-            _calc_stack.pop_back();
-            _calc_stack.pop_back();
+            _calc_stack.pop_back(2);
             ret = -1;
         }
         else
diff --git a/src/rpn-complex.hpp b/src/rpn-complex.hpp
index e84c995..f7ed82c 100644
--- a/src/rpn-complex.hpp
+++ b/src/rpn-complex.hpp
@@ -62,8 +62,7 @@ void r2c()
     complex* cplx = (complex*)_stack->allocate_back(complex::calc_size(), cmd_complex);
     CHECK_MPFR(mpfr_set(cplx->re()->mpfr, ((number*)_calc_stack.get_obj(1))->_value.mpfr, floating_t::s_mpfr_rnd));
     CHECK_MPFR(mpfr_set(cplx->im()->mpfr, ((number*)_calc_stack.get_obj(0))->_value.mpfr, floating_t::s_mpfr_rnd));
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
+    _calc_stack.pop_back(2);
 }
 
 void c2r()
diff --git a/src/rpn-real.hpp b/src/rpn-real.hpp
index c3a854b..0088210 100644
--- a/src/rpn-real.hpp
+++ b/src/rpn-real.hpp
@@ -182,10 +182,7 @@ void do_divide_complexes()
     CHECK_MPFR(mpfr_div(left->im()->mpfr, left->im()->mpfr, ex->_value.mpfr, floating_t::s_mpfr_rnd));
 
     _stack->pop_back();
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
+    _calc_stack.pop_back(4);
 }
 
 void div()
@@ -216,17 +213,18 @@ void div()
         //1. copy out
         stack::copy_and_push_back(*_stack, _stack->size()-1, _calc_stack);//complex
         stack::copy_and_push_back(*_stack, _stack->size()-2, _calc_stack);//number
-        _stack->pop_back();
-        _stack->pop_back();
+        _stack->pop_back(2);
+
         //2. copy back (2 complexes on stack)
         stack::copy_and_push_back(_calc_stack, _calc_stack.size()-2, *_stack);//complex back to stack
         stack::copy_and_push_back(_calc_stack, _calc_stack.size()-2, *_stack);//complex back to stack
+
         //3. set complex level 2 to (number,0)
         complex* new_cplx = (complex*)_stack->get_obj(1);
         CHECK_MPFR(mpfr_set(new_cplx->re()->mpfr, ((number*)_calc_stack.get_obj(0))->_value.mpfr, floating_t::s_mpfr_rnd));
         CHECK_MPFR(mpfr_set_ui(new_cplx->im()->mpfr, 0UL, floating_t::s_mpfr_rnd));
-        _calc_stack.pop_back();
-        _calc_stack.pop_back();
+        _calc_stack.pop_back(2);
+
         //4. divide
         do_divide_complexes();
     }
@@ -501,8 +499,7 @@ void mant()
             while (mpfr_less_p(left->_value.mpfr, one->_value.mpfr))
                 mpfr_mul(left->_value.mpfr, left->_value.mpfr, ten->_value.mpfr, floating_t::s_mpfr_rnd);
 
-            _calc_stack.pop_back();
-            _calc_stack.pop_back();
+            _calc_stack.pop_back(2);
         }
     }
     else
diff --git a/src/rpn-stack.hpp b/src/rpn-stack.hpp
index bda1a41..0eefc6b 100644
--- a/src/rpn-stack.hpp
+++ b/src/rpn-stack.hpp
@@ -4,12 +4,10 @@ void swap(void)
     MIN_ARGUMENTS(2);
     stack::copy_and_push_back(*_stack, _stack->size()-1, _calc_stack);
     stack::copy_and_push_back(*_stack, _stack->size()-2, _calc_stack);
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
+    (void)_stack->pop_back(2);
     stack::copy_and_push_back(_calc_stack, _calc_stack.size()-2, *_stack);
     stack::copy_and_push_back(_calc_stack, _calc_stack.size()-1, *_stack);
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
+    _calc_stack.pop_back(2);
 
 }
 void drop(void)
@@ -21,8 +19,7 @@ void drop(void)
 void drop2(void)
 {
     MIN_ARGUMENTS(2);
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
+    (void)_stack->pop_back(2);
 }
 
 void dropn(void)
@@ -33,14 +30,12 @@ void dropn(void)
     int args = (int)mpfr_get_si(((number*)_stack->back())->_value.mpfr, floating_t::s_mpfr_rnd);
     MIN_ARGUMENTS(args+1);
 
-    for(int i=0;i<args+1;i++)
-        (void)_stack->pop_back();
+    (void)_stack->pop_back(args+1);
 }
 
 void erase(void)
 {
-    while(_stack->size()>0)
-        (void)_stack->pop_back();
+    (void)_stack->pop_back(_stack->size());
 }
 
 void dup(void)
@@ -93,15 +88,11 @@ void rot(void)
     stack::copy_and_push_back(*_stack, _stack->size()-3, _calc_stack);
     stack::copy_and_push_back(*_stack, _stack->size()-2, _calc_stack);
     stack::copy_and_push_back(*_stack, _stack->size()-1, _calc_stack);
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
-    (void)_stack->pop_back();
+    (void)_stack->pop_back(3);
     stack::copy_and_push_back(_calc_stack, _calc_stack.size()-2, *_stack);
     stack::copy_and_push_back(_calc_stack, _calc_stack.size()-1, *_stack);
     stack::copy_and_push_back(_calc_stack, _calc_stack.size()-3, *_stack);
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
-    _calc_stack.pop_back();
+    _calc_stack.pop_back(3);
 }
 
 void depth(void)
@@ -130,8 +121,7 @@ void roll(void)
         stack::copy_and_push_back(_calc_stack, args-1-i, *_stack);
     stack::copy_and_push_back(_calc_stack, args-1, *_stack);
 
-    for(int i=0;i<args;i++)
-        _calc_stack.pop_back();
+    _calc_stack.pop_back(args);
 }
 
 void rolld(void)
@@ -154,8 +144,7 @@ void rolld(void)
     for(int i=1;i<args;i++)
         stack::copy_and_push_back(_calc_stack, _calc_stack.size()-i, *_stack);
 
-    for(int i=0;i<args;i++)
-        _calc_stack.pop_back();
+    _calc_stack.pop_back(args);
 }
 
 void over(void)
diff --git a/src/rpn-string.hpp b/src/rpn-string.hpp
index dc5683d..90e8af7 100644
--- a/src/rpn-string.hpp
+++ b/src/rpn-string.hpp
@@ -93,8 +93,7 @@ void strpos()
     if (found != NULL)
         pos = (long)(found - src)+1L;
 
-    _stack->pop_back();
-    _stack->pop_back();
+    _stack->pop_back(2);
 
     number* numb = (number*)_stack->allocate_back(number::calc_size(), cmd_number);
     numb->_value = pos;
@@ -112,8 +111,7 @@ void strsub()
     long len = ((ostring*)_stack->get_obj(2))->_len;
     bool result_is_void = false;
 
-    _stack->pop_back();
-    _stack->pop_back();
+    _stack->pop_back(2);
 
     if (first < 0)
         first = 0;
diff --git a/src/stack.hpp b/src/stack.hpp
index 9d30a70..99603c0 100644
--- a/src/stack.hpp
+++ b/src/stack.hpp
@@ -109,14 +109,18 @@ public:
         return allocated;
     }
 
-    object* pop_back()
+    object* pop_back(int pop_count = 1)
     {
         object* back = NULL;
 
-        if (_count > 0)
+        // pop several entries, return the last
+        while (pop_count-- > 0)
         {
-            _current = (char*)_base_pointer[--_count];
-            back = (object*)_current;
+            if (_count > 0)
+            {
+                _current = (char*)_base_pointer[--_count];
+                back = (object*)_current;
+            }
         }
 
         return back;