CMSIS-DSP  Version 1.9.0
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Variables
Complex FFT Tables
Complex FFT Functions

Variables

const uint16_t armBitRevTable [1024]
 Table for bit reversal process. More...
 
const uint64_t twiddleCoefF64_16 [32]
 Double Precision Floating-point Twiddle factors Table Generation. More...
 
const uint64_t twiddleCoefF64_32 [64]
 
const uint64_t twiddleCoefF64_64 [128]
 
const uint64_t twiddleCoefF64_128 [256]
 
const uint64_t twiddleCoefF64_256 [512]
 
const uint64_t twiddleCoefF64_512 [1024]
 
const uint64_t twiddleCoefF64_1024 [2048]
 
const uint64_t twiddleCoefF64_2048 [4096]
 
const uint64_t twiddleCoefF64_4096 [8192]
 
const float32_t twiddleCoef_16 [32]
 
const float32_t twiddleCoef_32 [64]
 
const float32_t twiddleCoef_64 [128]
 
const float32_t twiddleCoef_128 [256]
 
const float32_t twiddleCoef_256 [512]
 
const float32_t twiddleCoef_512 [1024]
 
const float32_t twiddleCoef_1024 [2048]
 
const float32_t twiddleCoef_2048 [4096]
 
const float32_t twiddleCoef_4096 [8192]
 
const q31_t twiddleCoef_16_q31 [24]
 Q31 Twiddle factors Table. More...
 
const q31_t twiddleCoef_32_q31 [48]
 
const q31_t twiddleCoef_64_q31 [96]
 
const q31_t twiddleCoef_128_q31 [192]
 
const q31_t twiddleCoef_256_q31 [384]
 
const q31_t twiddleCoef_512_q31 [768]
 
const q31_t twiddleCoef_1024_q31 [1536]
 
const q31_t twiddleCoef_2048_q31 [3072]
 
const q31_t twiddleCoef_4096_q31 [6144]
 
const q15_t twiddleCoef_16_q15 [24]
 q15 Twiddle factors Table More...
 
const q15_t twiddleCoef_32_q15 [48]
 
const q15_t twiddleCoef_64_q15 [96]
 
const q15_t twiddleCoef_128_q15 [192]
 
const q15_t twiddleCoef_256_q15 [384]
 
const q15_t twiddleCoef_512_q15 [768]
 
const q15_t twiddleCoef_1024_q15 [1536]
 
const q15_t twiddleCoef_2048_q15 [3072]
 
const q15_t twiddleCoef_4096_q15 [6144]
 
const float16_t twiddleCoefF16_16 [32]
 Floating-point Twiddle factors Table Generation. More...
 
const float16_t twiddleCoefF16_32 [64]
 
const float16_t twiddleCoefF16_64 [128]
 
const float16_t twiddleCoefF16_128 [256]
 
const float16_t twiddleCoefF16_256 [512]
 
const float16_t twiddleCoefF16_512 [1024]
 
const float16_t twiddleCoefF16_1024 [2048]
 
const float16_t twiddleCoefF16_2048 [4096]
 
const float16_t twiddleCoefF16_4096 [8192]
 
const float16_t twiddleCoefF16_rfft_32 [32]
 
const float16_t twiddleCoefF16_rfft_64 [64]
 
const float16_t twiddleCoefF16_rfft_128 [128]
 
const float16_t twiddleCoefF16_rfft_256 [256]
 
const float16_t twiddleCoefF16_rfft_512 [512]
 
const float16_t twiddleCoefF16_rfft_1024 [1024]
 
const float16_t twiddleCoefF16_rfft_2048 [2048]
 
const float16_t twiddleCoefF16_rfft_4096 [4096]
 

Description

Variable Documentation

const uint16_t armBitRevTable[1024]
Pseudo code for Generation of Bit reversal Table is 
for (l = 1; l <= N/4; l++)
{
  for (i = 0; i< logN2; i++)
  {
    a[i] = l & (1 << i);
  }
  for (j = 0; j < logN2; j++)
  {
    if (a[j] != 0)
    y[l] += (1 << ((logN2 - 1) - j));
  }
  y[l] = y[l] >> 1;
 }
where N = 4096, logN2 = 12
N is the maximum FFT Size supported
const float32_t twiddleCoef_1024[2048]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 1024, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_1024_q15[1536]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 1024, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_1024_q31[1536]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 1024, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_128[256]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 128, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_128_q15[192]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 128, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_128_q31[192]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i < 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 128, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_16[32]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i < N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 16, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_16_q15[24]
Example code for q15 Twiddle factors Generation:: 
fori = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 16, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_16_q31[24]
Example code for Q31 Twiddle factors Generation:: 
 for(i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 16, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_2048[4096]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 2048, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_2048_q15[3072]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 2048, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_2048_q31[3072]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 2048, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_256[512]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 256, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_256_q15[384]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 256, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_256_q31[384]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 256, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_32[64]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 32, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_32_q15[48]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 32, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_32_q31[48]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 32, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_4096[8192]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 4096, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_4096_q15[6144]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 4096, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_4096_q31[6144]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 4096, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_512[1024]
Example code for Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 512, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_512_q15[768]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 512, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_512_q31[768]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 512, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float32_t twiddleCoef_64[128]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i < N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 64, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const q15_t twiddleCoef_64_q15[96]
Example code for q15 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefq15[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefq15[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 64, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))
const q31_t twiddleCoef_64_q31[96]
Example code for Q31 Twiddle factors Generation:: 
for (i = 0; i< 3N/4; i++)
{
   twiddleCoefQ31[2*i]   = cos(i * 2*PI/(float)N);
   twiddleCoefQ31[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 64, PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))
const float16_t twiddleCoefF16_1024[2048]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 1024 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_128[256]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 128 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_16[32]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 16 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_2048[4096]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 2048 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_256[512]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 256 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_32[64]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 32 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_4096[8192]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 4096 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_512[1024]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 512 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_64[128]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
twiddleCoef[2*i]= cos(i * 2*PI/(float)N);
twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);
}
where N = 64 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const float16_t twiddleCoefF16_rfft_1024[1024]
const float16_t twiddleCoefF16_rfft_128[128]
const float16_t twiddleCoefF16_rfft_2048[2048]
const float16_t twiddleCoefF16_rfft_256[256]
const float16_t twiddleCoefF16_rfft_32[32]
Example code for Floating-point RFFT Twiddle factors Generation: 
TW = exp(pi/2*i-2*pi*i*[0:L/2-1]/L).'
Real and Imag values are in interleaved fashion
const float16_t twiddleCoefF16_rfft_4096[4096]
const float16_t twiddleCoefF16_rfft_512[512]
const float16_t twiddleCoefF16_rfft_64[64]
const uint64_t twiddleCoefF64_1024[2048]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 1024, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_128[256]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 128, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_16[32]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i < N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(double)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(double)N);
}
where N = 16, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_2048[4096]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 2048, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_256[512]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 256, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_32[64]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/N);
}
where N = 32, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_4096[8192]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 4096, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_512[1024]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for (i = 0; i< N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 512, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion
const uint64_t twiddleCoefF64_64[128]
Example code for Double Precision Floating-point Twiddle factors Generation: 
for(i = 0; i < N/; i++)
{
      twiddleCoef[2*i]   = cos(i * 2*PI/(float)N);
      twiddleCoef[2*i+1] = sin(i * 2*PI/(float)N);
}
where N = 64, PI = 3.14159265358979
Cos and Sin values are in interleaved fashion