diff --git a/INSTALL b/INSTALL
index f067f4b6..3fa05e9d 100644
--- a/INSTALL
+++ b/INSTALL
@@ -67,7 +67,8 @@ In step 1 you could add the following switches:
         finished and isn't entirely accurate it's advised to leave it on. 
 
 --disable-fpu-x86
-        disables the assembly fpu core. Although relatively new the x86 fpu 
+--disable-fpu-x64
+        disables the assembly fpu core. Although relatively new, the x86/x64 fpu 
         core has more accuracy then the regular fpu core. 
 
 --disable-dynamic-x86
diff --git a/configure.ac b/configure.ac
index 8cf01bdf..847d6d33 100644
--- a/configure.ac
+++ b/configure.ac
@@ -328,10 +328,11 @@ else
   AC_MSG_RESULT(no)
 fi 
 
-AH_TEMPLATE(C_FPU_X86,[Define to 1 to use a x86 assembly fpu core])
+AH_TEMPLATE(C_FPU_X86,[Define to 1 to use a x86/x64 assembly fpu core])
 AC_ARG_ENABLE(fpu-x86,AC_HELP_STRING([--disable-fpu-x86],[Disable x86 assembly fpu core]),,enable_fpu_x86=yes)
-AC_MSG_CHECKING(whether x86 assembly fpu core will be enabled) 
-if test x$enable_fpu_x86 = xno ; then 
+AC_ARG_ENABLE(fpu-x64,AC_HELP_STRING([--disable-fpu-x64],[Disable x64 assembly fpu core]),,enable_fpu_x64=yes)
+AC_MSG_CHECKING(whether the x86/x64 assembly fpu core will be enabled) 
+if test x$enable_fpu_x86 = xno -o x$enable_fpu_x64 = xno; then 
    AC_MSG_RESULT(no)
 else
   if test x$enable_fpu = xyes; then