added fft_twiddle_gen func that calculates twiddles inside provided arrays

C/FFT_FP_realisation.c

@@ -6,12 +6,18 @@
 static int64_t twiddle_re[TWIDDLE_L] = {0,};
 static int64_t twiddle_im[TWIDDLE_L] = {0,};
 
-void fft_fp_prepare(void){
+void fft_twiddle_gen(int64_t* tw_re, int64_t* tw_im){
 	for (uint32_t k = 0; k < TWIDDLE_L; ++k){
 		double angle = 2.0 * PI * k / DATA_L;
-		twiddle_re[k] = lround(cos(angle) * FP_acc);
-		twiddle_im[k] = lround(-sin(angle) * FP_acc);
-		printf("k, angle, tw_re, tw_im: %u %g %lld %lld\n", k, angle, (long long)twiddle_re[k], (long long)twiddle_im[k]);
+		tw_re[k] = lround(cos(angle) * FP_acc);
+		tw_im[k] = lround(-sin(angle) * FP_acc);
+	}
+}
+
+void fft_fp_prepare(void){
+	fft_twiddle_gen(twiddle_re, twiddle_im);
+	for (uint32_t k = 0; k < TWIDDLE_L; ++k){
+		printf("k, angle, tw_re, tw_im: %u %g %lld %lld\n", k, 2.0 * PI * k / DATA_L, (long long)twiddle_re[k], (long long)twiddle_im[k]);
 	}
 }
 

C/FFT_FP_realisation.h

@@ -19,6 +19,7 @@
 #define PI 3.141592653589793238462643383279502884197169399375105820974944
 #endif
 
+void fft_twiddle_gen(int64_t* twiddle_re, int64_t* twiddle_im);
 void fft_fp_prepare(void);
 void FFT_fp(int64_t* inp, uint32_t inp_L, int64_t* buf);