From 8db54c9c229da8c0e1eee92ecd569475559b35d3 Mon Sep 17 00:00:00 2001
From: Josh Stewart <josh@noisymime.org>
Date: Fri, 16 Jun 2017 22:31:42 +1000
Subject: [PATCH] MISRA work on maths.ino

---
 speeduino/maths.ino | 91 +++++++++++++++++++++++----------------------
 1 file changed, 47 insertions(+), 44 deletions(-)

diff --git a/speeduino/maths.ino b/speeduino/maths.ino
index 4c142533..a8d662b4 100644
--- a/speeduino/maths.ino
+++ b/speeduino/maths.ino
@@ -9,7 +9,7 @@ int fastMap(unsigned long x, int in_min, int in_max, int out_min, int out_max)
   //return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
 }
 
-//This is a dedicated function that specifically handles the case of mapping 0-1023 values into a 0 to X range 
+//This is a dedicated function that specifically handles the case of mapping 0-1023 values into a 0 to X range
 //This is a common case because it means converting from a standard 10-bit analog input to a byte or 10-bit analog into 0-511 (Eg the temperature readings)
 //int fastMap1023toX(unsigned long x, int in_min, int in_max, int out_min, int out_max)
 //removed ununsed variables, in_min and out_min is aways 0, in_max is aways 1023
@@ -24,61 +24,63 @@ Ref: http://www.hackersdelight.org/divcMore.pdf
 */
 
 //Unsigned divide by 10
-unsigned int divu10(unsigned int n) {
- unsigned long q, r;
- q = (n >> 1) + (n >> 2);
- q = q + (q >> 4);
- q = q + (q >> 8);
- q = q + (q >> 16);
- q = q >> 3;
- r = n - q*10;
- return q + ((r + 6) >> 4);
-// return q + (r > 9);
+unsigned int divu10(unsigned int n)
+{
+  unsigned long q, r;
+  q = (n >> 1) + (n >> 2);
+  q = q + (q >> 4);
+  q = q + (q >> 8);
+  q = q + (q >> 16);
+  q = q >> 3;
+  r = n - (q * 10);
+  return q + ((r + 6) >> 4);
 }
 
 //Signed divide by 10
-int divs10(long n) {
- long q, r;
- n = n + (n>>31 & 9);
- q = (n >> 1) + (n >> 2);
- q = q + (q >> 4);
- q = q + (q >> 8);
- q = q + (q >> 16);
- q = q >> 3;
- r = n - q*10;
- return q + ((r + 6) >> 4);
-// return q + (r > 9);
+int divs10(long n)
+{
+  long q, r, p;
+  p = n + (n>>31 & 9);
+  q = (p >> 1) + (p >> 2);
+  q = q + (q >> 4);
+  q = q + (q >> 8);
+  q = q + (q >> 16);
+  q = q >> 3;
+  r = p - (q * 10);
+  return q + ((r + 6) >> 4);
 }
 
 //Signed divide by 100
-int divs100(long n) {
+int divs100(long n)
+{
   return (n / 100); // Amazingly, gcc is producing a better /divide by 100 function than this
- long q, r;
- n = n + (n>>31 & 99);
- q = (n >> 1) + (n >> 3) + (n >> 6) - (n >> 10) +
- (n >> 12) + (n >> 13) - (n >> 16);
- q = q + (q >> 20);
- q = q >> 6;
- r = n - q*100;
- return q + ((r + 28) >> 7);
-// return q + (r > 99);
+  /*
+  long q, r;
+  n = n + (n>>31 & 99);
+  q = (n >> 1) + (n >> 3) + (n >> 6) - (n >> 10) +
+  (n >> 12) + (n >> 13) - (n >> 16);
+  q = q + (q >> 20);
+  q = q >> 6;
+  r = n - q*100;
+  return q + ((r + 28) >> 7);
+  */
 }
 
 //Unsigned divide by 100
-unsigned long divu100(unsigned long n) {
-  //return (n / 100); // No difference with this on/off
- unsigned long q, r;
- q = (n >> 1) + (n >> 3) + (n >> 6) - (n >> 10) +
- (n >> 12) + (n >> 13) - (n >> 16);
- q = q + (q >> 20);
- q = q >> 6;
- r = n - q*100;
- return q + ((r + 28) >> 7);
-// return q + (r > 99);
+unsigned long divu100(unsigned long n)
+{
+  //return (n / 100);
+  unsigned long q, r;
+  q = (n >> 1) + (n >> 3) + (n >> 6) - (n >> 10) +
+  (n >> 12) + (n >> 13) - (n >> 16);
+  q = q + (q >> 20);
+  q = q >> 6;
+  r = n - (q * 100);
+  return q + ((r + 28) >> 7);
 }
 
 //Return x percent of y
-//This is a relatively fast approximation of a percentage value. 
+//This is a relatively fast approximation of a percentage value.
 unsigned long percentage(byte x, unsigned long y)
 {
   return (y * x) / 100; //For some reason this is faster
@@ -91,7 +93,8 @@ unsigned long percentage(byte x, unsigned long y)
 inline long powint(int factor, unsigned int exponent)
 {
    long product = 1;
-   while (exponent--)
+   unsigned int counter = exponent;
+   while ( (counter--) > 0)
       product *= factor;
    return product;
 }