diff --git a/src/Adafruit_AHRS_Madgwick.cpp b/src/Adafruit_AHRS_Madgwick.cpp
index d8234ff..14aef48 100644
--- a/src/Adafruit_AHRS_Madgwick.cpp
+++ b/src/Adafruit_AHRS_Madgwick.cpp
@@ -280,15 +280,17 @@ void Adafruit_Madgwick::updateIMU(float gx, float gy, float gz, float ax,
 // Fast inverse square-root
 // See: http://en.wikipedia.org/wiki/Fast_inverse_square_root
 
-float Adafruit_Madgwick::invSqrt(float x) {
-  float halfx = 0.5f * x;
-  float y = x;
-  long i = *(long *)&y;
-  i = 0x5f3759df - (i >> 1);
-  y = *(float *)&i;
-  y = y * (1.5f - (halfx * y * y));
-  y = y * (1.5f - (halfx * y * y));
-  return y;
+float Adafruit_Madgwick::invSqrt(float x)
+{
+ 	float halfx = 0.5f * x;
+ 	union {
+ 	  float    f;
+ 	  uint32_t i;
+ 	} conv = { .f = x };
+ 	conv.i = 0x5f3759df - (conv.i >> 1);
+ 	conv.f *= 1.5f - (halfx * conv.f * conv.f);
+ 	conv.f *= 1.5f - (halfx * conv.f * conv.f);
+ 	return y;
 }
 
 //-------------------------------------------------------------------------------------------
diff --git a/src/Adafruit_AHRS_Mahony.cpp b/src/Adafruit_AHRS_Mahony.cpp
index c01b510..c0e0693 100644
--- a/src/Adafruit_AHRS_Mahony.cpp
+++ b/src/Adafruit_AHRS_Mahony.cpp
@@ -259,15 +259,17 @@ void Adafruit_Mahony::updateIMU(float gx, float gy, float gz, float ax,
 // Fast inverse square-root
 // See: http://en.wikipedia.org/wiki/Fast_inverse_square_root
 
-float Adafruit_Mahony::invSqrt(float x) {
-  float halfx = 0.5f * x;
-  float y = x;
-  long i = *(long *)&y;
-  i = 0x5f3759df - (i >> 1);
-  y = *(float *)&i;
-  y = y * (1.5f - (halfx * y * y));
-  y = y * (1.5f - (halfx * y * y));
-  return y;
+float Adafruit_Mahony::invSqrt(float x)
+{
+ 	float halfx = 0.5f * x;
+ 	union {
+ 	  float    f;
+ 	  uint32_t i;
+ 	} conv = { .f = x };
+ 	conv.i = 0x5f3759df - (conv.i >> 1);
+ 	conv.f *= 1.5f - (halfx * conv.f * conv.f);
+ 	conv.f *= 1.5f - (halfx * conv.f * conv.f);
+ 	return y;
 }
 
 //-------------------------------------------------------------------------------------------