From a1bce2b54d7d6a0c6ee33930031f77c2c0c7ab17 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 17 Nov 2016 16:23:22 +1100
Subject: [PATCH] AP_Compass: use get_random16()

---
 libraries/AP_Compass/CompassCalibrator.cpp | 11 +----------
 libraries/AP_Compass/CompassCalibrator.h   |  2 --
 2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/libraries/AP_Compass/CompassCalibrator.cpp b/libraries/AP_Compass/CompassCalibrator.cpp
index 0f7039c3c1..b07f4df2ec 100644
--- a/libraries/AP_Compass/CompassCalibrator.cpp
+++ b/libraries/AP_Compass/CompassCalibrator.cpp
@@ -371,7 +371,7 @@ void CompassCalibrator::thin_samples() {
     // shuffle the samples http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
     // this is so that adjacent samples don't get sequentially eliminated
     for(uint16_t i=_samples_collected-1; i>=1; i--) {
-        uint16_t j = get_random() % (i+1);
+        uint16_t j = get_random16() % (i+1);
         CompassSample temp = _sample_buffer[i];
         _sample_buffer[i] = _sample_buffer[j];
         _sample_buffer[j] = temp;
@@ -686,15 +686,6 @@ void CompassCalibrator::run_ellipsoid_fit()
 }
 
 
-uint16_t CompassCalibrator::get_random(void)
-{
-    static uint32_t m_z = 1234;
-    static uint32_t m_w = 76542;
-    m_z = 36969 * (m_z & 65535) + (m_z >> 16);
-    m_w = 18000 * (m_w & 65535) + (m_w >> 16);
-    return ((m_z << 16) + m_w) & 0xFFFF;
-}
-
 //////////////////////////////////////////////////////////
 //////////// CompassSample public interface //////////////
 //////////////////////////////////////////////////////////
diff --git a/libraries/AP_Compass/CompassCalibrator.h b/libraries/AP_Compass/CompassCalibrator.h
index 16c1ef14aa..ed814afbea 100644
--- a/libraries/AP_Compass/CompassCalibrator.h
+++ b/libraries/AP_Compass/CompassCalibrator.h
@@ -135,6 +135,4 @@ private:
      * Reset and update #_completion_mask with the current samples.
      */
     void update_completion_mask();
-
-    uint16_t get_random();
 };