Minor sin_f32_table correction and comments

firmware/common/sine_table.hpp

@@ -35,7 +35,10 @@ w = numpy.arange(length, dtype=numpy.float64) * (2 * numpy.pi / length)
 v = numpy.sin(w)
 print(v)
 */
-constexpr uint16_t sine_table_f32_period = 256;
+constexpr uint16_t sine_table_f32_period = 256;	
+// periode is 256 . means sine_table_f32[0]= sine_table_f32[0+256], sine_table_f32[1]=sine_table_f32[1+256] (those two added manualy)
+// Then table has 257 values , [0,..255] + [256] and [257], those two are  used when we interpolate[255] with [255+1], and [256] with [256+1]
+// [256] index is needed in the function sin_f32() when we are inputing very small radian values , example , sin_f32((-1e-14) in radians) 
 
 static constexpr std::array<float, sine_table_f32_period + 2> sine_table_f32{
 	 0.00000000e+00,   2.45412285e-02,   4.90676743e-02,
@@ -123,7 +126,7 @@ static constexpr std::array<float, sine_table_f32_period + 2> sine_table_f32{
 	-2.42980180e-01,  -2.19101240e-01,  -1.95090322e-01,
 	-1.70961889e-01,  -1.46730474e-01,  -1.22410675e-01,
 	-9.80171403e-02,  -7.35645636e-02,  -4.90676743e-02,
-	-2.45412285e-02,   0.00000000e+00,  0.00000000e+00
+	-2.45412285e-02,   0.00000000e+00,   2.45412285e-02
 };
 
 inline float sin_f32(const float w) {