From cad7efa639e67e12a7135931af15fd7d51a8096e Mon Sep 17 00:00:00 2001
From: Matt Mascarenhas <matt@handmadedev.org>
Date: Mon, 29 Aug 2016 21:58:14 +0100
Subject: [PATCH] Accelerate HMM_Power() with the squaring technique

Thanks to @mmozeiko for the algorithm
---
 HandmadeMath.h | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/HandmadeMath.h b/HandmadeMath.h
index 5e6c8e9..540d512 100644
--- a/HandmadeMath.h
+++ b/HandmadeMath.h
@@ -598,28 +598,22 @@ HMM_Length(hmm_vec3 A)
 HINLINE float
 HMM_Power(float Base, int Exponent)
 {
-    float Result = 1;
-
-    if(Exponent > 0)
+    float Result = 1.0f;
+    float Mul = Exponent < 0 ? 1.f / Base : Base;
+    unsigned int X = Exponent < 0 ? -Exponent : Exponent;
+    while (X)
     {
-        int i;
-        for(i = 0; i < Exponent; ++i)
+        if (X & 1)
         {
-            Result *= Base;
+            Result *= Mul;
         }
+        Mul *= Mul;
+        X >>= 1;
     }
-    else
-    {
-        int i;
-        for(i = 0; i > Exponent; --i)
-        {
-            Result /= Base;
-        }
-    }
-
     return (Result);
 }
 
+
 HINLINE float
 HMM_Lerp(float A, float Time, float B)
 {