函数说明
void DSPF_sp_fftSPxSP ( int N,
float * ptr_x,
float * ptr_w,
float * ptr_y,
unsigned char * brev,
int n_min,
int offset,
int n_max
)
The benchmark performs a mixed radix forwards fft.
Parameters:
N length of FFT in complex samples
ptr_x pointer to complex data input
ptr_w pointer to complex twiddle factor
ptr_y pointer to complex output data
brev pointer to bit reverse table containing 64 entries
n_min should be 4 if N can be represented as Power of 4 else, n_min should be 2
offset index in complex samples of sub-fft from start of main fft
n_max size of main fft in complex samples
Algorithm:
DSPF_sp_fftSPxSP_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:
N needs to be power of 2
8 <= N <= 131072, 32 <= N for linear assembly implementation
Arrays pointed by ptr_x, ptr_w, and ptr_y should not overlap
Arrays pointed by ptr_x, ptr_w, and ptr_y should align on the double words boundary
Implementation Notes:
Interruptibility: The code is interrupt-tolerant but not interruptible.
Endian Support: The code supports both big and little endian modes.
但是我看到TI库里的例子却是#pragma DATA_ALIGN(x_i, 8); 这样写的8字节对齐，我的意思double Words 不就是4字节对齐么 为什么会写8？？？
