DSP_fft16x16t
if (radix == 2) |
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{ |
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n02 | = x_8 | + x_a; | n03 | = x_9 | + x_b; |
n22 | = x_8 | − x_a; | n23 | = x_9 | − x_b; |
n12 | = x_c + x_e; | n13 | = x_d + x_f; | ||
n32 | = x_c − x_e; | n33 | = x_d − x_f; | ||
}
/*−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−*/
/* | Points that are | read | from succesive | locations map to y, y[N/4] | */ |
/* | y[N/2], y[3N/4] | in a | radix4 scheme, | y, y[N/8], y[N/2],y[5N/8] | */ |
/*−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−*/
y0[2*h2+2] = n02; | y0[2*h2+3] = n03; |
y1[2*h2+2] = n12; | y1[2*h2+3] = n13; |
y2[2*h2+2] = n22; | y2[2*h2+3] = n23; |
y3[2*h2+2] = n32; | y3[2*h2+3] = n33; |
/*−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−*/ /* Increment ”j” by ”j0”. If j equals n0, then increment both ”x0” */
/* and ”x2” so that double inversion is avoided.*/
/*−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−*/ j += j0;
if (j == n0)
{
j += n0;
x0 += (int) npoints>>1;
x2 += (int) npoints>>1;
}
}
}
C64x+ DSPLIB Reference |
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