写一段CCS5.5的c语言代码，内容是实现基2的FFT，256点数，能够实现一个信号是复数数组的实部，另一个信号是数组的虚部，进行FFT变换。

以下是一个基于CCS5.5的C语言代码，实现了基2的FFT，可以对256点数进行FFT变换。该代码能够处理包含复数数组的实部和虚部的两个信号。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define N 256

//定义复数结构体
typedef struct {
    float real;
    float imag;
} complex;

//计算旋转因子
void calc_twiddle(int n, complex *twiddle_factors) {
    int i;
    for (i = 0; i < n; i++) {
        twiddle_factors[i].real = cos(2 * M_PI * i / n);
        twiddle_factors[i].imag = -sin(2 * M_PI * i / n);
    }
}

//FFT变换
void fft(complex *x, int n) {
    int i, j, k;
    int n1, n2;
    complex t, u;

    //计算旋转因子
    complex *twiddle_factors = (complex *) malloc(sizeof(complex) * n / 2);
    calc_twiddle(n / 2, twiddle_factors);

    //开始FFT变换
    for (i = 1, j = 0; i < n; i++) {
        //计算位逆序置换
        int bit = n / 2;
        while (!((j ^= bit) & bit)) {
            bit /= 2;
        }

        if (i < j) {
            //交换数据
            t = x[i];
            x[i] = x[j];
            x[j] = t;
        }
    }

    for (n1 = 2; n1 <= n; n1 <<= 1) {
        n2 = n1 / 2;
        for (j = 0; j < n; j += n1) {
            for (k = j; k < j + n2; k++) {
                //计算蝴蝶运算
                t.real = x[k + n2].real * twiddle_factors[k - j].real - x[k + n2].imag * twiddle_factors[k - j].imag;
                t.imag = x[k + n2].real * twiddle_factors[k - j].imag + x[k + n2].imag * twiddle_factors[k - j].real;
                u.real = x[k].real;
                u.imag = x[k].imag;
                x[k].real = u.real + t.real;
                x[k].imag = u.imag + t.imag;
                x[k + n2].real = u.real - t.real;
                x[k + n2].imag = u.imag - t.imag;
            }
        }
    }
}

int main() {
    //生成测试数据
    complex input[N];
    complex output[N];
    int i;
    for (i = 0; i < N; i++) {
        input[i].real = sin(2 * M_PI * i / N);
        input[i].imag = 0;
    }

    //FFT变换
    fft(input, N);

    //输出结果
    for (i = 0; i < N; i++) {
        printf("Input[%d]: (%.3f, %.3f)\t Output[%d]: (%.3f, %.3f)\n",
               i, input[i].real, input[i].imag, i, output[i].real, output[i].imag);
    }

    return 0;
}