Move IIR struct and configs to common/.

firmware/common/dsp_iir.cpp

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "dsp_iir.hpp"
+
+#include <hal.h>
+
+void IIRBiquadFilter::configure(const iir_biquad_config_t& new_config) {
+	config = new_config;
+}
+
+void IIRBiquadFilter::execute(const buffer_f32_t& buffer_in, const buffer_f32_t& buffer_out) {
+	const auto a_ = config.a;
+	const auto b_ = config.b;
+	
+	auto x_ = x;
+	auto y_ = y;
+
+	// TODO: Assert that buffer_out.count == buffer_in.count.
+	for(size_t i=0; i<buffer_out.count; i++) {
+		x_[0] = x_[1];
+		x_[1] = x_[2];
+		x_[2] = buffer_in.p[i];
+
+		y_[0] = y_[1];
+		y_[1] = y_[2];
+		y_[2] = b_[0] * x_[2] + b_[1] * x_[1] + b_[2] * x_[0]
+		                      - a_[1] * y_[1] - a_[2] * y_[0];
+
+		buffer_out.p[i] = y_[2];
+	}
+
+	x = x_;
+	y = y_;
+}
+
+void IIRBiquadFilter::execute_in_place(const buffer_f32_t& buffer) {
+	execute(buffer, buffer);
+}