AP_Math: change fast_atan2 to use atan2f on fast CPUs

libraries/AP_Math/AP_Math.cpp

@@ -38,13 +38,14 @@ float fast_atan(float v)
     return (v*(1.6867629106f + v2*0.4378497304f)/(1.6867633134f + v2));
 }
 
-#define FAST_ATAN2_PIBY2_FLOAT  1.5707963f
-// fast_atan2 - faster version of atan2
-//      126 us on AVR cpu vs 199 for regular atan2
-//      absolute error is < 0.005 radians or 0.28 degrees
-//      origin source: https://gist.github.com/volkansalma/2972237/raw/
-float fast_atan2(float y, float x)
-{
+#if HAL_CPU_CLASS < HAL_CPU_CLASS_75 || CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
+    #define FAST_ATAN2_PIBY2_FLOAT  1.5707963f
+    // fast_atan2 - faster version of atan2
+    //      126 us on AVR cpu vs 199 for regular atan2
+    //      absolute error is < 0.005 radians or 0.28 degrees
+    //      origin source: https://gist.github.com/volkansalma/2972237/raw/
+    float fast_atan2(float y, float x)
+    {
         if (x == 0.0f) {
             if (y > 0.0f) {
                 return FAST_ATAN2_PIBY2_FLOAT;
@@ -71,7 +72,13 @@ float fast_atan2(float y, float x)
             }
         }
         return atan;
-}
+    }
+#else
+    float fast_atan2(float y, float x)
+    {
+        return atan2f(y,x);
+    }
+#endif
 
 #if ROTATION_COMBINATION_SUPPORT
 // find a rotation that is the combination of two other