From 776035ee9eed5bbaae6c36f41dbb3a29e80b27e7 Mon Sep 17 00:00:00 2001
From: Petro Karashchenko <petro.karashchenko@gmail.com>
Date: Sun, 29 Sep 2024 23:12:33 +0200
Subject: [PATCH] nuttx/libm: fix powl wrong if first parameter is negative

Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
---
 libs/libm/libm/lib_powl.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/libs/libm/libm/lib_powl.c b/libs/libm/libm/lib_powl.c
index f3b97e4fddc..a71de03d02e 100644
--- a/libs/libm/libm/lib_powl.c
+++ b/libs/libm/libm/lib_powl.c
@@ -41,6 +41,22 @@
 #ifdef CONFIG_HAVE_LONG_DOUBLE
 long double powl(long double b, long double e)
 {
-  return expl(e * logl(b));
+  if (b > 0.0)
+    {
+      return expl(e * logl(b));
+    }
+  else if (b < 0.0 && e == (int)e)
+    {
+      if ((int)e % 2 == 0)
+        {
+          return expl(e * logl(fabsl(b)));
+        }
+      else
+        {
+          return -expl(e * logl(fabsl(b)));
+        }
+    }
+
+  return 0.0;
 }
 #endif