From 4f81a60ef662886009f8a596485f6dafeb58d064 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Tue, 31 May 2016 06:31:04 -0600
Subject: [PATCH] Add a NAN test on 'x' in asin function of lib_asin.c. 
 Suggested by Pierre-noel Bouteville.

---
 libc/math/lib_asin.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libc/math/lib_asin.c b/libc/math/lib_asin.c
index 08a2dc9573..2f45a24a1d 100644
--- a/libc/math/lib_asin.c
+++ b/libc/math/lib_asin.c
@@ -3,7 +3,7 @@
  *
  * This file is a part of NuttX:
  *
- *   Copyright (C) 2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012, 2015-2016 Gregory Nutt. All rights reserved.
  *   Ported by: Darcy Gong
  *
  * It derives from the Rhombs OS math library by Nick Johnson which has
@@ -55,7 +55,7 @@ double asin(double x)
 
   /* Verify that the input value is in the domain of the function */
 
-  if (x < -1.0 || x > 1.0)
+  if (x < -1.0 || x > 1.0 || isnan(x))
     {
       return NAN;
     }