1 files changed, 14 insertions, 0 deletions
diff --git a/winsup/mingw/mingwex/math/isnan.c b/winsup/mingw/mingwex/math/isnan.c
new file mode 100644
index 000000000..b38bc290e
--- /dev/null
+++ b/winsup/mingw/mingwex/math/isnan.c
@@ -0,0 +1,14 @@
+#include <math.h>
+
+int
+__isnan (double _x)
+{
+  unsigned short _sw;
+  __asm__ ("fxam;"
+	   "fstsw %%ax": "=a" (_sw) : "t" (_x));
+  return (_sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL))
+    == FP_NAN;
+}
+
+#undef isnan
+int __attribute__ ((alias ("__isnan"))) isnan (double);