diff --git a/src/constant.h b/src/constant.h
index 280a717..5714513 100644
--- a/src/constant.h
+++ b/src/constant.h
@@ -1,25 +1,33 @@
+// default values
+//
+
 // default mode and number of printed digits
 //
 #define DEFAULT_MODE number::std
 #define DEFAULT_PRECISION 20
+#define MPFR_DEFAULT_FORMAT "%.20Rg"
 
-// MPFR related constants
+// MPFR related defaults
 //
 
 // rounding method
-#define MPFR_DEF_RND MPFR_RNDN
+#define MPFR_DEFAULT_RND MPFR_RNDN
+
 // 128 bits significand precision
 #define MPFR_DEFAULT_PREC_BITS 128
+
 // 128 bits significand storing length in bytes, result of mpfr_custom_get_size(128)
 #define MPFR_DEFAULT_STORING_LENGTH_BYTES 16
 
+// constants
+//
+
 // show formats
 #define MPFR_FORMAT_BEG "%."
 #define MPFR_FORMAT_STD "Rg"
 #define MPFR_FORMAT_FIX "Rf"
 #define MPFR_FORMAT_SCI "Re"
 #define MPFR_FORMAT_HEX "%Ra"
-#define MPFR_FORMAT "%.20Rg"
 
 #define MPFR_RND_STRINGS { "nearest", "toward zero", "toward +inf", "toward -inf", "away from zero" }
 
diff --git a/src/parse.h b/src/parse.h
index 7a86fce..7a314a1 100644
--- a/src/parse.h
+++ b/src/parse.h
@@ -340,7 +340,7 @@ static bool get_number(const string& entry, program& prog, string& remaining_ent
         {
             number* num = (number*)prog.allocate_back(number::calc_size(), cmd_number);
 
-            int mpfr_ret = mpfr_strtofr(num->_value.mpfr, entry.c_str(), &endptr, 0, MPFR_DEF_RND);
+            int mpfr_ret = mpfr_strtofr(num->_value.mpfr, entry.c_str(), &endptr, 0, MPFR_DEFAULT_RND);
             if (endptr != NULL && endptr != entry.c_str())
             {
                 // determine representation
diff --git a/src/rpn-branch.h b/src/rpn-branch.h
index 4078f79..ce1181d 100644
--- a/src/rpn-branch.h
+++ b/src/rpn-branch.h
@@ -125,7 +125,7 @@ int rpn_next(branch& myobj)
     }
 
     // increment then test
-    mpfr_add_si(myobj.farg1->_value.mpfr, myobj.farg1->_value.mpfr, 1UL, MPFR_DEF_RND);
+    mpfr_add_si(myobj.farg1->_value.mpfr, myobj.farg1->_value.mpfr, 1UL, MPFR_DEFAULT_RND);
 
     // for command: increment symbol too
     if (start_or_for->arg1 != -1)
@@ -181,7 +181,7 @@ int rpn_step(branch& myobj)
         }
 
         // increment then test
-        mpfr_add(myobj.farg1->_value.mpfr, myobj.farg1->_value.mpfr, step->_value.mpfr, MPFR_DEF_RND);
+        mpfr_add(myobj.farg1->_value.mpfr, myobj.farg1->_value.mpfr, step->_value.mpfr, MPFR_DEFAULT_RND);
 
         // for command: increment symbol too
         if (start_or_for->arg1 != -1)
diff --git a/src/rpn-general.h b/src/rpn-general.h
index d99ab69..5da11a4 100644
--- a/src/rpn-general.h
+++ b/src/rpn-general.h
@@ -168,7 +168,7 @@ void round()
     
     ostring* str = (ostring*)_stack->pop_back();
     bool done = false;
-    for(int rnd = (int)MPFR_DEF_RND; rnd <= (int)MPFR_RNDA; rnd++)
+    for(int rnd = (int)MPFR_DEFAULT_RND; rnd <= (int)MPFR_RNDA; rnd++)
     {
         if (string(s_mpfr_rnd_str[rnd]) == str->_value)
         {
diff --git a/src/rpn.cpp b/src/rpn.cpp
index 0d1db54..383004b 100644
--- a/src/rpn.cpp
+++ b/src/rpn.cpp
@@ -41,11 +41,11 @@ extern "C" {
 #include <fstream>
 using namespace std;
 
-static string s_mpfr_printf_format = string(MPFR_FORMAT);
+static string s_mpfr_printf_format = string(MPFR_DEFAULT_FORMAT);
 static mpfr_prec_t s_mpfr_prec = MPFR_DEFAULT_PREC_BITS;
 static unsigned int s_mpfr_prec_bytes = MPFR_DEFAULT_STORING_LENGTH_BYTES;
 
-static mpfr_rnd_t s_mpfr_rnd = MPFR_DEF_RND;
+static mpfr_rnd_t s_mpfr_rnd = MPFR_DEFAULT_RND;
 static const char* s_mpfr_rnd_str[5] = MPFR_RND_STRINGS;
 
 //