diff --git a/src/simulator/cairo-wideint-private.h b/src/core/cairo-wideint-private.h
similarity index 99%
rename from src/simulator/cairo-wideint-private.h
rename to src/core/cairo-wideint-private.h
index bbbca4fd7..5b407ef14 100644
--- a/src/simulator/cairo-wideint-private.h
+++ b/src/core/cairo-wideint-private.h
@@ -32,7 +32,7 @@
 #ifndef CAIRO_WIDEINT_H
 #define CAIRO_WIDEINT_H
 
-#include "ns3/simulator-config.h"
+#include "ns3/core-config.h"
 #define cairo_private 
 #define HAVE_UINT64_T 1
 
diff --git a/src/simulator/cairo-wideint.c b/src/core/cairo-wideint.c
similarity index 100%
rename from src/simulator/cairo-wideint.c
rename to src/core/cairo-wideint.c
diff --git a/src/simulator/int64x64-128.cc b/src/core/int64x64-128.cc
similarity index 100%
rename from src/simulator/int64x64-128.cc
rename to src/core/int64x64-128.cc
diff --git a/src/simulator/int64x64-128.h b/src/core/int64x64-128.h
similarity index 100%
rename from src/simulator/int64x64-128.h
rename to src/core/int64x64-128.h
diff --git a/src/simulator/int64x64-cairo.cc b/src/core/int64x64-cairo.cc
similarity index 100%
rename from src/simulator/int64x64-cairo.cc
rename to src/core/int64x64-cairo.cc
diff --git a/src/simulator/int64x64-cairo.h b/src/core/int64x64-cairo.h
similarity index 100%
rename from src/simulator/int64x64-cairo.h
rename to src/core/int64x64-cairo.h
diff --git a/src/simulator/int64x64-double.h b/src/core/int64x64-double.h
similarity index 100%
rename from src/simulator/int64x64-double.h
rename to src/core/int64x64-double.h
diff --git a/src/simulator/int64x64.cc b/src/core/int64x64.cc
similarity index 100%
rename from src/simulator/int64x64.cc
rename to src/core/int64x64.cc
diff --git a/src/simulator/int64x64.h b/src/core/int64x64.h
similarity index 98%
rename from src/simulator/int64x64.h
rename to src/core/int64x64.h
index a6466a5fa..797160017 100644
--- a/src/simulator/int64x64.h
+++ b/src/core/int64x64.h
@@ -1,7 +1,7 @@
 #ifndef INT64X64_H
 #define INT64X64_H
 
-#include "ns3/simulator-config.h"
+#include "ns3/core-config.h"
 
 #if defined (INT64X64_USE_DOUBLE)
 #include "int64x64-double.h"
diff --git a/src/core/wscript b/src/core/wscript
index ae8b29f56..747ad0722 100644
--- a/src/core/wscript
+++ b/src/core/wscript
@@ -2,7 +2,41 @@
 import sys
 import Options
 
+def set_options(opt):
+    opt.add_option('--int64x64-as-double',
+                   help=('Whether to use a double floating point'
+                         ' type for int64x64 values'
+                         ' WARNING: this option only has effect '
+                         'with the configure command.'),
+                   action="store_true", default=False,
+                   dest='int64x64_as_double')
+
+
 def configure(conf):
+    a = conf.check(type_name='uint128_t', define_name='HAVE_UINT128_T')
+    b = conf.check(type_name='__uint128_t', define_name='HAVE___UINT128_T')
+
+
+    if Options.options.int64x64_as_double:
+        conf.define('INT64X64_USE_DOUBLE', 1)
+        conf.env['INT64X64_USE_DOUBLE'] = 1
+        highprec = 'long double'
+    elif a or b:
+        conf.define('INT64X64_USE_128', 1)
+        conf.env['INT64X64_USE_128'] = 1
+        highprec = '128-bit integer'
+    else:
+        conf.define('INT64X64_USE_CAIRO', 1)
+        conf.env['INT64X64_USE_CAIRO'] = 1
+        highprec = 'cairo 128-bit integer'
+
+    conf.check_message_custom('high precision time', 'implementation', highprec)
+
+    conf.check(header_name='stdint.h', define_name='HAVE_STDINT_H')
+    conf.check(header_name='inttypes.h', define_name='HAVE_INTTYPES_H')
+
+    conf.check(header_name='sys/inttypes.h', define_name='HAVE_SYS_INT_TYPES_H')
+
     if conf.check(header_name='stdlib.h'):
         conf.define('HAVE_STDLIB_H', 1)
         conf.define('HAVE_GETENV', 1)
@@ -81,6 +115,7 @@ def build(bld):
         'traced-callback-test-suite.cc',
         'ptr-test-suite.cc',
         'fatal-impl.cc',
+        'int64x64.cc',
         ]
 
     headers = bld.new_task_gen('ns3header')
@@ -130,6 +165,7 @@ def build(bld):
         'vector.h',
         'default-deleter.h',
         'fatal-impl.h',
+        'int64x64.h',
         ]
 
     if sys.platform == 'win32':
@@ -154,6 +190,21 @@ def build(bld):
                 'system-condition.h',
                 ])
 
+    env = bld.env_of_name('default')
+    if env['INT64X64_USE_DOUBLE']:
+        headers.source.extend(['int64x64-double.h'])
+    elif env['INT64X64_USE_128']:
+        headers.source.extend(['int64x64-128.h'])
+        core.source.extend(['int64x64-128.cc'])
+    elif env['INT64X64_USE_CAIRO']:
+        core.source.extend([
+            'int64x64-cairo.cc',
+            ])
+        headers.source.extend([
+            'int64x64-cairo.h',
+            'cairo-wideint-private.h',
+            ])
+
     if bld.env['ENABLE_GSL']:
         core.uselib = 'GSL GSLCBLAS M'
         core.source.extend(['rng-test-suite.cc'])
diff --git a/src/simulator/nstime.h b/src/simulator/nstime.h
index 75558e6f2..76db04dc0 100644
--- a/src/simulator/nstime.h
+++ b/src/simulator/nstime.h
@@ -23,7 +23,7 @@
 #include "ns3/assert.h"
 #include "ns3/attribute.h"
 #include "ns3/attribute-helper.h"
-#include "int64x64.h"
+#include "ns3/int64x64.h"
 #include <stdint.h>
 #include <math.h>
 #include <ostream>
diff --git a/src/simulator/wscript b/src/simulator/wscript
index 906aa703c..7d4c57daa 100644
--- a/src/simulator/wscript
+++ b/src/simulator/wscript
@@ -1,46 +1,8 @@
 ## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 import sys
 
-import Options
-
-
-def set_options(opt):
-    opt.add_option('--high-precision-as-double',
-                   help=('Whether to use a double floating point'
-                         ' type for high precision time values'
-                         ' WARNING: this option only has effect '
-                         'with the configure command.'),
-                   action="store_true", default=False,
-                   dest='high_precision_as_double')
-
 
 def configure(conf):
-    a = conf.check(type_name='uint128_t', define_name='HAVE_UINT128_T')
-    b = conf.check(type_name='__uint128_t', define_name='HAVE___UINT128_T')
-
-
-    if Options.options.high_precision_as_double:
-        conf.define('INT64X64_USE_DOUBLE', 1)
-        conf.env['USE_HIGH_PRECISION_DOUBLE'] = 1
-        highprec = 'long double'
-    elif a or b:
-        conf.define('INT64X64_USE_128', 1)
-        conf.env['USE_HIGH_PRECISION_128'] = 1
-        highprec = '128-bit integer'
-    else:
-        conf.define('INT64X64_USE_CAIRO', 1)
-        conf.env['USE_HIGH_PRECISION_CAIRO'] = 1
-        highprec = 'cairo 128-bit integer'
-
-    conf.check_message_custom('high precision time', 'implementation', highprec)
-
-    conf.check(header_name='stdint.h', define_name='HAVE_STDINT_H')
-    conf.check(header_name='inttypes.h', define_name='HAVE_INTTYPES_H')
-
-    conf.check(header_name='sys/inttypes.h', define_name='HAVE_SYS_INT_TYPES_H')
-
-    conf.write_config_header('ns3/simulator-config.h', top=True)
-
     if not conf.check(lib='rt', uselib='RT', define_name='HAVE_RT'):
         conf.report_optional_feature("RealTime", "Real Time Simulator",
                                      False, "librt is not available")
@@ -54,7 +16,6 @@ def configure(conf):
 def build(bld):
     sim = bld.create_ns3_module('simulator', ['core'])
     sim.source = [
-        'int64x64.cc',
         'time.cc',
         'event-id.cc',
         'scheduler.cc',
@@ -76,7 +37,6 @@ def build(bld):
     headers = bld.new_task_gen('ns3header')
     headers.module = 'simulator'
     headers.source = [
-        'int64x64.h',
         'nstime.h',
         'event-id.h',
         'event-impl.h',
@@ -98,20 +58,6 @@ def build(bld):
         ]
 
     env = bld.env_of_name('default')
-    if env['USE_HIGH_PRECISION_DOUBLE']:
-        headers.source.extend(['int64x64-double.h'])
-    elif env['USE_HIGH_PRECISION_128']:
-        headers.source.extend(['int64x64-128.h'])
-        sim.source.extend(['int64x64-128.cc'])
-    elif env['USE_HIGH_PRECISION_CAIRO']:
-        sim.source.extend([
-            'int64x64-cairo.cc',
-            ])
-        headers.source.extend([
-            'int64x64-cairo.h',
-            'cairo-wideint-private.h',
-            ])
-
     if env['ENABLE_REAL_TIME']:
         headers.source.extend([
                 'realtime-simulator-impl.h',
diff --git a/src/wscript b/src/wscript
index b833636c7..1d0ce6f0c 100644
--- a/src/wscript
+++ b/src/wscript
@@ -64,7 +64,7 @@ all_modules = (
     )
 
 def set_options(opt):
-    opt.sub_options('simulator')
+    opt.sub_options('core')
 
     opt.add_option('--enable-rpath',
                    help=("Link programs with rpath"