Definition in file op_kfix_cos.c.
#include "dsp.h"
Go to the source code of this file.
Functions | |
dsp16_t | dsp16_op_kernel_cosfix (dsp16_t angle) |
dsp32_t | dsp32_op_kernel_cosfix (dsp32_t angle) |
Definition at line 49 of file op_kfix_cos.c.
References DSP16_Q, and DSP16_QB.
Referenced by dsp16_op_sin().
00050 { 00051 // Coefficients of the 4th order Tchebychev polynom to calculate a cosine. 00052 const dsp16_t c0 = DSP16_Q(1.); 00053 const dsp16_t c2 = DSP16_Q(0.61651611328125); 00054 const dsp16_t c4 = DSP16_Q(0.1231689453125); 00055 S32 z, suma; 00056 00057 // Computation of the polynom 00058 z = (angle*angle) >> (DSP16_QB - 3); 00059 suma = c2 - ((z*c4) >> (DSP16_QB + 1)); 00060 00061 return (c0 - ((z*suma) >> DSP16_QB)); 00062 }
Definition at line 65 of file op_kfix_cos.c.
References DSP32_Q, and DSP32_QB.
Referenced by dsp32_op_sin().
00066 { 00067 // Coefficients of the 12th order Tchebychev polynom to calculate a cosine. 00068 const dsp32_t one = DSP32_Q(1.); 00069 const dsp32_t half = DSP32_Q(0.61685027507); //0.5*(pi^2/8); 00070 const dsp32_t C1 = DSP32_Q(0.50733903092); //(4.1666667908e-02*pi^2)*(pi^2/8); 00071 const dsp32_t C2 = DSP32_Q(-0.16690785015); //(-1.3888889225e-03*pi^4)*(pi^2/8); 00072 const dsp32_t C3 = DSP32_Q(0.02941632920); //(2.4801587642e-05*pi^6)*(pi^2/8); 00073 const dsp32_t C4 = DSP32_Q(-0.00322586085); //(-2.7557314297e-07*pi^8)*(pi^2/8); 00074 const dsp32_t C5 = DSP32_Q(0.00024118485); //(2.0875723372e-09*pi^10)*(pi^2/8); 00075 const dsp32_t C6 = DSP32_Q(-0.00001295308); //(-1.1359647598e-11*pi^12)*(pi^2/8); 00076 long long z, suma, produ; 00077 00078 // Computation of the polynom 00079 z = (long long) angle; 00080 z = (z*z) >> DSP32_QB; 00081 00082 produ = (z*C6) >> DSP32_QB; 00083 00084 suma = C5 + produ; 00085 produ = (z*suma) >> DSP32_QB; 00086 suma = C4 + produ; 00087 produ = (z*suma) >> DSP32_QB; 00088 suma = C3 + produ; 00089 produ = (z*suma) >> DSP32_QB; 00090 suma = C2 + produ; 00091 produ = (z*suma) >> DSP32_QB; 00092 suma = C1 + produ; 00093 produ = (z*suma) >> DSP32_QB; 00094 produ = z*produ; 00095 00096 return (one - (((half*z - produ)) >> (DSP32_QB - 3))); 00097 }