Merge pull request #262 from runger1101001/sine_optimisations

make foc_utils functions WEAK

Author: runger1101001

src/common/foc_utils.cpp

@@ -1,17 +1,18 @@
 #include "foc_utils.h"
 
-// int array instead of float array
-// 4x200 points per 360 deg
-// 2x storage save (int 2Byte float 4 Byte )
-// sin*10000
-const int sine_array[200] = {0,79,158,237,316,395,473,552,631,710,789,867,946,1024,1103,1181,1260,1338,1416,1494,1572,1650,1728,1806,1883,1961,2038,2115,2192,2269,2346,2423,2499,2575,2652,2728,2804,2879,2955,3030,3105,3180,3255,3329,3404,3478,3552,3625,3699,3772,3845,3918,3990,4063,4135,4206,4278,4349,4420,4491,4561,4631,4701,4770,4840,4909,4977,5046,5113,5181,5249,5316,5382,5449,5515,5580,5646,5711,5775,5839,5903,5967,6030,6093,6155,6217,6279,6340,6401,6461,6521,6581,6640,6699,6758,6815,6873,6930,6987,7043,7099,7154,7209,7264,7318,7371,7424,7477,7529,7581,7632,7683,7733,7783,7832,7881,7930,7977,8025,8072,8118,8164,8209,8254,8298,8342,8385,8428,8470,8512,8553,8594,8634,8673,8712,8751,8789,8826,8863,8899,8935,8970,9005,9039,9072,9105,9138,9169,9201,9231,9261,9291,9320,9348,9376,9403,9429,9455,9481,9506,9530,9554,9577,9599,9621,9642,9663,9683,9702,9721,9739,9757,9774,9790,9806,9821,9836,9850,9863,9876,9888,9899,9910,9920,9930,9939,9947,9955,9962,9969,9975,9980,9985,9989,9992,9995,9997,9999,10000,10000};
 
 // function approximating the sine calculation by using fixed size array
 // ~40us (float array)
 // ~50us (int array)
 // precision +-0.005
 // it has to receive an angle in between 0 and 2PI
-float _sin(float a){
+__attribute__((weak)) float _sin(float a){
+  // int array instead of float array
+  // 4x200 points per 360 deg
+  // 2x storage save (int 2Byte float 4 Byte )
+  // sin*10000
+  static const uint16_t sine_array[200] = {0,79,158,237,316,395,473,552,631,710,789,867,946,1024,1103,1181,1260,1338,1416,1494,1572,1650,1728,1806,1883,1961,2038,2115,2192,2269,2346,2423,2499,2575,2652,2728,2804,2879,2955,3030,3105,3180,3255,3329,3404,3478,3552,3625,3699,3772,3845,3918,3990,4063,4135,4206,4278,4349,4420,4491,4561,4631,4701,4770,4840,4909,4977,5046,5113,5181,5249,5316,5382,5449,5515,5580,5646,5711,5775,5839,5903,5967,6030,6093,6155,6217,6279,6340,6401,6461,6521,6581,6640,6699,6758,6815,6873,6930,6987,7043,7099,7154,7209,7264,7318,7371,7424,7477,7529,7581,7632,7683,7733,7783,7832,7881,7930,7977,8025,8072,8118,8164,8209,8254,8298,8342,8385,8428,8470,8512,8553,8594,8634,8673,8712,8751,8789,8826,8863,8899,8935,8970,9005,9039,9072,9105,9138,9169,9201,9231,9261,9291,9320,9348,9376,9403,9429,9455,9481,9506,9530,9554,9577,9599,9621,9642,9663,9683,9702,9721,9739,9757,9774,9790,9806,9821,9836,9850,9863,9876,9888,9899,9910,9920,9930,9939,9947,9955,9962,9969,9975,9980,9985,9989,9992,9995,9997,9999,10000,10000};
+
   if(a < _PI_2){
     //return sine_array[(int)(199.0f*( a / (_PI/2.0)))];
     //return sine_array[(int)(126.6873f* a)];           // float array optimized
@@ -36,15 +37,15 @@ float _sin(float a){
 // ~56us (int array)
 // precision +-0.005
 // it has to receive an angle in between 0 and 2PI
-float _cos(float a){
+__attribute__((weak)) float _cos(float a){
   float a_sin = a + _PI_2;
   a_sin = a_sin > _2PI ? a_sin - _2PI : a_sin;
   return _sin(a_sin);
 }
 
 
 // normalizing radian angle to [0,2PI]
-float _normalizeAngle(float angle){
+__attribute__((weak)) float _normalizeAngle(float angle){
   float a = fmod(angle, _2PI);
   return a >= 0 ? a : (a + _2PI);
 }
@@ -57,15 +58,13 @@ float _electricalAngle(float shaft_angle, int pole_pairs) {
 // square root approximation function using
 // https://reprap.org/forum/read.php?147,219210
 // https://en.wikipedia.org/wiki/Fast_inverse_square_root
-float _sqrtApprox(float number) {//low in fat
-  long i;
-  float y;
+__attribute__((weak)) float _sqrtApprox(float number) {//low in fat
   // float x;
   // const float f = 1.5F; // better precision
 
   // x = number * 0.5F;
-  y = number;
-  i = * ( long * ) &y;
+  float y = number;
+  long i = * ( long * ) &y;
   i = 0x5f375a86 - ( i >> 1 );
   y = * ( float * ) &i;
   // y = y * ( f - ( x * y * y ) ); // better precision