X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=FFT.mc;h=5969315c8a174d1cadc4b8e49e60bee63f813f1c;hb=7a5f3f2a9974d0fa0f3c888944d9120b22f254eb;hp=3ad081668c51b058cece7d041f772a5c415ad94c;hpb=a62dbd706365d44bdcac9f8ac4c7c6dd05484642;p=matthijs%2Fprojects%2Fmontium-fft.git

diff --git a/FFT.mc b/FFT.mc
index 3ad0816..5969315 100644
--- a/FFT.mc
+++ b/FFT.mc
@@ -6,6 +6,7 @@
 
 #include "FFT.h"
 
+int stage = 1;
 /**
  * Executes a single butterfly on ALU 0-3. The inputs are the words taken from
  * in, which will be read on various inputs of ALU 0-3. Outputs will be
@@ -51,7 +52,7 @@ INLINE void write_output_regular(struct mems m, struct bf_out res, bool second_h
 	add_offset(m.output_b_re, 2);
 	add_offset(m.output_b_im, 2);
 	
-	if (second_half) {
+	if (!second_half) {
 		write_mem(m.output_a_re, res.a_re);
 		write_mem(m.output_a_im, res.a_im);
 		write_mem(m.output_b_re, res.b_re);
@@ -98,7 +99,13 @@ INLINE struct bf_in read_input_regular(struct mems m, bool cycle_odd, bool stage
 	add_offset(m.input_a_im, 1);
 	add_offset(m.input_b_re, 1);
 	add_offset(m.input_b_im, 1);
-	/* TODO: Update twiddle offsets */
+	
+	/* TODO: Is this true? */
+	add_offset(m.twiddle_re, (PARAM_N_t>>stage));
+	add_offset(m.twiddle_im, (PARAM_N_t>>stage));
+	use_mask(m.twiddle_re, (PARAM_N_t/2)-1);
+	use_mask(m.twiddle_im, (PARAM_N_t/2)-1);
+
 	return in;
 }
 
@@ -180,8 +187,8 @@ INLINE void do_half_regular_stage(struct mems m, bool stage_odd, bool second_hal
 
 	/* Now, do half a single stage. That means N_t / 4 cycles. Since we do 2
 	 * cycles on every iteration, plus one before and after the loop,
-	 * we will loop N_t / 8 - 1 times. */
-	init_loop(LC2, (PARAM_N_t / 8) - 1);
+	 * we will loop N_t / 8 - 1 times. We add an extra - 1 because this is a do while loop... */
+	init_loop(LC2, (PARAM_N_t / 8) - 1 - 1);
 	do {
 		/* Write outputs of previous cycle */
 		write_output_regular(m, out, second_half);
@@ -247,8 +254,8 @@ void run() {
 	struct mems m;
 
 	/* We need to do n_t regular stages. Since we do two stages each
-	 * iteration, we'll do n_t / 2 iterations. */
-	init_loop(LC1, (PARAM_n_t / 2));
+	 * iteration, we'll do n_t / 2 iterations (and a -1 because we check after looping) */
+	init_loop(LC1, (PARAM_n_t / 2) - 1);
 	do {
 		m = init_mem_mapping(EVEN_STAGE);
 		init_input_addresses_regular(m, EVEN_STAGE);
@@ -256,11 +263,13 @@ void run() {
 		next_cycle();
 		do_half_regular_stage(m, EVEN_STAGE, FIRST_HALF);
 		do_half_regular_stage(m, EVEN_STAGE, SECOND_HALF);
+		stage++;
 		next_cycle();
 		init_input_addresses_regular(m, ODD_STAGE);
 		m = init_mem_mapping(ODD_STAGE);
 		next_cycle();
 		do_half_regular_stage(m, ODD_STAGE, FIRST_HALF);
 		do_half_regular_stage(m, ODD_STAGE, SECOND_HALF);
+		stage++;
 	} while (loop_next(LC1));
 }