X-Git-Url: https://git.stderr.nl/gitweb?p=matthijs%2Fprojects%2Fmontium-fft.git;a=blobdiff_plain;f=FFT_support.cpp;h=2ddf150b6f1bb8e3e215dac89d9256cbb4fe31cd;hp=6f21e5a24afa1e9cca6fe74a37bfa4965ff6d2ea;hb=HEAD;hpb=1efd07a9676d63cd5ffe6535ee45101e87f89c86

diff --git a/FFT_support.cpp b/FFT_support.cpp
index 6f21e5a..2ddf150 100644
--- a/FFT_support.cpp
+++ b/FFT_support.cpp
@@ -2,9 +2,8 @@
 #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
@@ -28,7 +27,7 @@ float from_fixed(int n)
 	return n / (float)(1<<FIXED_POINT);
 }
 
-void print_mem(mem m, int offset, int size, bool fixed)
+void print_mem(mem m, int offset, int size, bool fixed, bool newline)
 {
 	int i;
 	for(i = offset;i<offset+size;i++)
@@ -37,12 +36,12 @@ void print_mem(mem m, int offset, int size, bool fixed)
 			printf("%0.4f", from_fixed(get_mem(m->id, i)));
 		else
 			printf("%04hx", (short)get_mem(m->id, i));
-		if ((i + 1) % WORDS_PER_LINE == 0)
+		if (newline && (i + 1) % WORDS_PER_LINE == 0)
 			printf("\n");
 		else if ((i + 1) % WORDS_PER_GROUP == 0)
 			printf(" ");
 	}
-	if (i % WORDS_PER_LINE != 0)
+	if (newline && i % WORDS_PER_LINE != 0)
 		printf("\n");
 }
 
@@ -55,46 +54,98 @@ void pre_run()
 	input_a_im   = alloc_mem(P1M0);
 	input_b_re   = alloc_mem(P2M0);
 	input_b_im   = alloc_mem(P3M0);
-	output_a_re  = alloc_mem(P0M1);
-	output_a_im  = alloc_mem(P1M1);
-	output_b_re  = alloc_mem(P2M1);
-	output_b_im  = alloc_mem(P3M1);
+	
+	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 20*2*Pi, ie twenty periods. We divide 
+		 * the value by PARAM_N_t to prevent overflow. */
+		int value = to_fixed(sin((float)i*20*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, true);
 	printf("im(W)\n");
-	print_mem(twiddle_im, 0, SIZE, true);
+	print_mem(twiddle_im, 0, PARAM_N_t/2, true, 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, 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, true);
+
+	printf("re_in = [");
+	print_mem(input_a_re, 0, PARAM_N_t/2, true, false);
+	print_mem(input_b_re, 0, PARAM_N_t/2, true, false);
+	printf("];\n");
+
+/* 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 = [");
+	print_mem(output_a_re, 0, PARAM_N_t/2, true, false);
+	print_mem(output_b_re, 0, PARAM_N_t/2, true, false);
+	printf("];\n");
+	printf("im_out = [");
+	print_mem(output_a_im, 0, PARAM_N_t/2, true, false);
+	print_mem(output_b_im, 0, PARAM_N_t/2, true, false);
+	printf("];\n");
+	/*
+	printf("re(out)\n");
+	print_mem(output_a_re, 0, PARAM_N_t/2, false, true);
+	print_mem(output_b_re, 0, PARAM_N_t/2, false, true);
+	printf("im(out)\n");
+	print_mem(output_a_im, 0, PARAM_N_t/2, false, true);
+	print_mem(output_b_im, 0, PARAM_N_t/2, false, true);
+	*/
+
 }