diff --git a/configure.ac b/configure.ac
index 91949944..14457955 100644
--- a/configure.ac
+++ b/configure.ac
@@ -70,8 +70,6 @@ AS_IF([test "x$EMSCRIPTEN" != "x"],[
   AC_MSG_WARN([compiling to javascript - asm implementations disabled])
 ])
 
-AS_CASE([$host], [x86_64-*-mingw*|x86_64-*-cygwin*|x86_64-*-msys], [enable_asm="no"])
-
 AC_ARG_ENABLE(pie,
 [AS_HELP_STRING(--disable-pie,Do not produce position independent executables)],
  enable_pie=$enableval, enable_pie="maybe")
@@ -326,6 +324,9 @@ AS_IF([test "$enable_asm" != "no"],[
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
   ]], [[
 #if defined(__amd64) || defined(__amd64__) || defined(__x86_64__)
+# if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) || defined(_WIN32) || defined(_WIN64)
+#  error Windows x86_64 calling conventions are not supported yet
+# endif
 /* neat */
 #else
 # error !amd64