This routine is used to compute the inverse, complex, radix-2, decimation-infrequency Fast Fourier Transform of a single-precision complex sequence of size n, and a power of 2. The routine requires bit-reversed input and bit-reversed coefficents (twiddle factors) and produces results that are in normal order.
@param x Input and output sequences (dim-n) (input/output) x has n complex numbers (2*n SP values). The real and imaginary
values are interleaved in memory. The input is in bit-reversed order nad output is in normal order.
@param w FFT coefficients (dim-n/2) (input) w has n/2 complex numbers (n SP values). FFT coeficients must be in
bit-reversed order. The real and imaginary values are interleaved in memory.
@param n FFT size (input).
- Algorithm:
- DSPF_sp_icfftr2_dif_cn.c is the natural C equivalent of the optimized linear assembly code without restrictions. Note that the linear assembly code is optimized and restrictions may apply.
- Assumptions:
- Both input x and coefficient w should be aligned on double-word boundary.
x should be padded with 4 words.
n should be greater than 8.
- Implementation Notes:
- Interruptibility: The code is interrupt-tolerant but not interruptible.
Endian Support: The code supports both big and little endian modes.