From a310b0952f9329ea483e642c6b55c6e52f041fcb Mon Sep 17 00:00:00 2001
From: zouboan <fft@feedforward.com.cn>
Date: Fri, 21 Jan 2022 22:46:34 +0800
Subject: [PATCH] bug patch for frexpf function

---
 libs/libc/math/lib_frexpf.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/libs/libc/math/lib_frexpf.c b/libs/libc/math/lib_frexpf.c
index 76284fd3a81..e8a6b1feb44 100644
--- a/libs/libc/math/lib_frexpf.c
+++ b/libs/libc/math/lib_frexpf.c
@@ -37,6 +37,21 @@
 
 float frexpf(float x, int *exponent)
 {
-  *exponent = (int)ceilf(log2f(x));
-  return x / ldexpf(1.0F, *exponent);
+  float res;
+
+  *exponent = (int)ceilf(log2f(fabsf(x)));
+  res = x / ldexpf(1.0F, *exponent);
+  if (res >= 1.0)
+    {
+      res -= 0.5;
+      *exponent += 1;
+    }
+
+  if (res <= -1.0)
+    {
+      res += 0.5;
+      *exponent += 1;
+    }
+
+  return res;
 }