X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=FFT_support.cpp;h=7fc2484be97043c091505e99354a165015e2e2a1;hb=00b2c5a7eced88e39b762255d361d61f78e2abe3;hp=1876e36ce4302e6cae6511d7113c976b637bcdc6;hpb=e09e88b193ec1b84311b345abb2b9d7943060602;p=matthijs%2Fprojects%2Fmontium-fft.git

diff --git a/FFT_support.cpp b/FFT_support.cpp
index 1876e36..7fc2484 100644
--- a/FFT_support.cpp
+++ b/FFT_support.cpp
@@ -2,17 +2,14 @@
 #include <cstdio>
 #include <cmath>
 
-
-/* Didn't the Montium use Q15 instead of Q14? */
-#define FIXED_POINT 14
+/* Use Q15 fixed point format (1 sign bit plus 15 fractional bits) */
+#define FIXED_POINT 15
 #define WORD_SIZE   16
 
-#define WORDS_PER_LINE 4
+#define WORDS_PER_LINE 8
 #define WORDS_PER_GROUP 1
 
-extern 	mem input_a_re, input_a_im, input_b_re, input_b_im, output_a_re, output_a_im, output_b_re, output_b_im, twiddle_re, twiddle_im; 
-
-
+mem input_a_re, input_a_im, input_b_re, input_b_im, output_a_re, output_a_im, output_b_re, output_b_im, twiddle_re, twiddle_im; 
 
 int to_fixed(float n)
 {
@@ -52,42 +49,95 @@ void print_mem(mem m, int offset, int size, bool fixed)
 void pre_run()
 {
 	int i;
-
+	/* Assign memories, at least for the first stage */
+	input_a_re   = alloc_mem(P0M0);
+	input_a_im   = alloc_mem(P1M0);
+	input_b_re   = alloc_mem(P2M0);
+	input_b_im   = alloc_mem(P3M0);
+	
+	twiddle_re   = alloc_mem(P4M0);
+	twiddle_im   = alloc_mem(P4M1);
+	
 	/* TODO: Init memory and twiddles */
-	for (i=0;i<SIZE/2;i++)
+	for (i=0;i<PARAM_N_t/2;i++)
 	{
-		set_mem(twiddle_re->id, i, to_fixed(cos(2*M_PI/SIZE*i)));
-		set_mem(twiddle_im->id, i, to_fixed(sin(2*M_PI/SIZE*i)));
+		set_mem(twiddle_re->id, i, to_fixed(cos(i*2*M_PI/PARAM_N_t)));
+		set_mem(twiddle_im->id, i, to_fixed(sin(i*2*M_PI/PARAM_N_t)));
 	}
 	
-	for (i=0;i<SIZE;i++)
+	for (i=0;i<PARAM_N_t;i++)
 	{
-		int value = to_fixed(sin((float)i/SIZE*2*2*M_PI));
-		if (i<SIZE/2)
+		/* We take the sine from 0 to 2*2*Pi, ie two periods. We divide 
+		 * the value by PARAM_N_t to prevent overflow. */
+		int value = to_fixed(sin((float)i*2*2*M_PI/PARAM_N_t)/PARAM_N_t);
+
+		if (i<PARAM_N_t/2)
 		{
-			set_mem(input_a_re->id, i, value);
-			set_mem(input_a_im->id, i, 0);
+			if (i % 2 == 0) {
+				set_mem(input_a_re->id, i, value);
+				set_mem(input_a_im->id, i, 0);
+			} else {
+				set_mem(input_b_re->id, i, value);
+				set_mem(input_b_im->id, i, 0);
+			}
 		}
 		else
 		{
-			set_mem(input_a_re->id, i - SIZE / 2, value);
-			set_mem(input_a_im->id, i - SIZE / 2, 0);
+			if (i % 2 == 0) {
+				set_mem(input_b_re->id, i - PARAM_N_t/2, value);
+				set_mem(input_b_im->id, i - PARAM_N_t/2, 0);
+			} else {
+				set_mem(input_a_re->id, i - PARAM_N_t/2, value);
+				set_mem(input_a_im->id, i - PARAM_N_t/2, 0);
+			}
 		}
 	}
-}
-
-void post_run()
-{
+	
 	printf("re(W)\n");
-	print_mem(twiddle_re, 0, SIZE, true);
+	print_mem(twiddle_re, 0, PARAM_N_t/2, true);
 	printf("im(W)\n");
-	print_mem(twiddle_im, 0, SIZE, true);
+	print_mem(twiddle_im, 0, PARAM_N_t/2, true);
 	printf("re(in_a)\n");
-	print_mem(input_a_re, 0, SIZE, true);
+	print_mem(input_a_re, 0, PARAM_N_t/2, true);
 	printf("re(in_b)\n");
-	print_mem(input_b_re, 0, SIZE, true);
-	printf("re(out_a)\n");
-	print_mem(output_a_re, 0, SIZE, true);
-	printf("im(out_a)\n");
-	print_mem(output_a_im, 0, SIZE, true);
+	print_mem(input_b_re, 0, PARAM_N_t/2, true);
+	
+/* Write out memory contents for use by the python simulator */
+	save_mem_range_to_file(input_a_re->id, 0, PARAM_N_t/2, "Memory/sin_a_re.mm");
+	save_mem_range_to_file(input_a_im->id, 0, PARAM_N_t/2, "Memory/sin_a_im.mm");
+	save_mem_range_to_file(input_b_re->id, 0, PARAM_N_t/2, "Memory/sin_b_re.mm");
+	save_mem_range_to_file(input_b_im->id, 0, PARAM_N_t/2, "Memory/sin_b_im.mm");
+	save_mem_range_to_file(twiddle_re->id, 0, PARAM_N_t/2, "Memory/twiddle_re.mm");
+	save_mem_range_to_file(twiddle_im->id, 0, PARAM_N_t/2, "Memory/twiddle_im.mm");
+}
+
+void post_run()
+{
+	if (PARAM_n_t % 2 == 0) {
+		/* When the number of stages is even, the 
+		 * outputs end up at the left memories again */
+		output_a_re  = alloc_mem(P0M0);
+		output_a_im  = alloc_mem(P1M0);
+		output_b_re  = alloc_mem(P2M0);
+		output_b_im  = alloc_mem(P3M0);
+	} else {
+		output_a_re  = alloc_mem(P0M1);
+		output_a_im  = alloc_mem(P1M1);
+		output_b_re  = alloc_mem(P2M1);
+		output_b_im  = alloc_mem(P3M1);
+	}
+	printf("re(out)\n");
+	print_mem(output_a_re, 0, PARAM_N_t/2, true);
+	print_mem(output_b_re, 0, PARAM_N_t/2, true);
+	printf("im(out)\n");
+	print_mem(output_a_im, 0, PARAM_N_t/2, true);
+	print_mem(output_b_im, 0, PARAM_N_t/2, true);
+	
+	printf("re(out)\n");
+	print_mem(output_a_re, 0, PARAM_N_t/2, false);
+	print_mem(output_b_re, 0, PARAM_N_t/2, false);
+	printf("im(out)\n");
+	print_mem(output_a_im, 0, PARAM_N_t/2, false);
+	print_mem(output_b_im, 0, PARAM_N_t/2, false);
+
 }