diff --git a/src/Make_cyg.mak b/src/Make_cyg.mak
index 2b7fce9..e35e2e3 100644
--- a/src/Make_cyg.mak
+++ b/src/Make_cyg.mak
@@ -229,18 +229,26 @@
 ifneq ($(wildcard $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/i386-mingw32),)
 RUBY_PLATFORM = i386-mingw32
 else
+ifneq ($(wildcard $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/x64-mingw32),)
+RUBY_PLATFORM = x64-mingw32
+else
 RUBY_PLATFORM = i386-mswin32
 endif
 endif
 endif
+endif
 
 ifndef RUBY_INSTALL_NAME
 ifeq ($(RUBY_VER), 16)
 RUBY_INSTALL_NAME = mswin32-ruby$(RUBY_API_VER)
 else
+ifeq ($(ARCH),x86-64)
+RUBY_INSTALL_NAME = x64-msvcrt-ruby$(RUBY_API_VER)
+else
 RUBY_INSTALL_NAME = msvcrt-ruby$(RUBY_API_VER)
 endif
 endif
+endif
 
 ifeq (19, $(word 1,$(sort 19 $(RUBY_VER))))
 RUBY_19_OR_LATER = 1
diff --git a/src/Make_ming.mak b/src/Make_ming.mak
index 695b7e7..b8d7b20 100644
--- a/src/Make_ming.mak
+++ b/src/Make_ming.mak
@@ -288,18 +288,26 @@
 ifneq ($(wildcard $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/i386-mingw32),)
 RUBY_PLATFORM = i386-mingw32
 else
+ifneq ($(wildcard $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/x64-mingw32),)
+RUBY_PLATFORM = x64-mingw32
+else
 RUBY_PLATFORM = i386-mswin32
 endif
 endif
 endif
+endif
 
 ifndef RUBY_INSTALL_NAME
 ifeq ($(RUBY_VER), 16)
 RUBY_INSTALL_NAME = mswin32-ruby$(RUBY_API_VER)
 else
+ifeq ($(ARCH),x86-64)
+RUBY_INSTALL_NAME = x64-msvcrt-ruby$(RUBY_API_VER)
+else
 RUBY_INSTALL_NAME = msvcrt-ruby$(RUBY_API_VER)
 endif
 endif
+endif
 
 ifeq (19, $(word 1,$(sort 19 $(RUBY_VER))))
 RUBY_19_OR_LATER = 1
diff --git a/src/if_ruby.c b/src/if_ruby.c
index 818aacb..d810d37 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -39,6 +39,9 @@
  */
 # define rb_cFalseClass		(*dll_rb_cFalseClass)
 # define rb_cFixnum		(*dll_rb_cFixnum)
+# if defined(DYNAMIC_RUBY_VER) && DYNAMIC_RUBY_VER >= 20
+#  define rb_cFloat		(*dll_rb_cFloat)
+# endif
 # define rb_cNilClass		(*dll_rb_cNilClass)
 # define rb_cSymbol		(*dll_rb_cSymbol)
 # define rb_cTrueClass		(*dll_rb_cTrueClass)
@@ -249,6 +252,9 @@
 static VALUE (*dll_rb_assoc_new) (VALUE, VALUE);
 VALUE *dll_rb_cFalseClass;
 VALUE *dll_rb_cFixnum;
+#if defined(DYNAMIC_RUBY_VER) && DYNAMIC_RUBY_VER >= 20
+VALUE *dll_rb_cFloat;
+#endif
 VALUE *dll_rb_cNilClass;
 static VALUE *dll_rb_cObject;
 VALUE *dll_rb_cSymbol;
@@ -352,7 +358,7 @@
 {
     return dll_rb_float_new(d);
 }
-unsigned long rb_num2ulong(VALUE x)
+VALUE rb_num2ulong(VALUE x)
 {
     return (long)RSHIFT((SIGNED_VALUE)(x),1);
 }
@@ -373,6 +379,9 @@
     {"rb_assoc_new", (RUBY_PROC*)&dll_rb_assoc_new},
     {"rb_cFalseClass", (RUBY_PROC*)&dll_rb_cFalseClass},
     {"rb_cFixnum", (RUBY_PROC*)&dll_rb_cFixnum},
+#if defined(DYNAMIC_RUBY_VER) && DYNAMIC_RUBY_VER >= 20
+    {"rb_cFloat", (RUBY_PROC*)&dll_rb_cFloat},
+#endif
     {"rb_cNilClass", (RUBY_PROC*)&dll_rb_cNilClass},
     {"rb_cObject", (RUBY_PROC*)&dll_rb_cObject},
     {"rb_cSymbol", (RUBY_PROC*)&dll_rb_cSymbol},
diff --git a/src/version.c b/src/version.c
index 309f656..c6ce9c2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -729,6 +729,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    848,
+/**/
     847,
 /**/
     846,