viterbi decoder: separate viterbi implementations

reorganizes viterbi decoder source so that each implementation resides in a separate file.
2016-11-03 21:35:29 -04:00
parent c6502ae022
commit 9cf628359b
8 changed files with 554 additions and 192 deletions
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2016 Bastian Bloessl <bloessl@ccs-labs.org>
+ *
+ * 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef INCLUDED_IEEE802_11_VITERBI_DECODER_X86_H
+#define INCLUDED_IEEE802_11_VITERBI_DECODER_X86_H
+
+#include <xmmintrin.h>
+#include "utils.h"
+
+namespace gr {
+namespace ieee802_11 {
+
+// Maximum number of traceback bytes
+#define TRACEBACK_MAX 24
+
+/* This Viterbi decoder was taken from the gr-dvbt module of
+ * GNU Radio. It is an SSE2 version of the Viterbi Decoder
+ * created by Phil Karn. The SSE2 version was made by Bogdan
+ * Diaconescu. For more info see: gr-dvbt/lib/d_viterbi.h
+ */
+class viterbi_decoder
+{
+public:
+
+	viterbi_decoder();
+	virtual ~viterbi_decoder();
+
+	uint8_t* decode(ofdm_param *ofdm, frame_param *frame, uint8_t *in);
+
+private:
+
+	// Position in circular buffer where the current decoded byte is stored
+	int d_store_pos;
+	// Metrics for each state
+	unsigned char d_mmresult[64] __attribute__((aligned(16)));
+	// Paths for each state
+	unsigned char d_ppresult[TRACEBACK_MAX][64] __attribute__((aligned(16)));
+
+
+	union branchtab27 {
+		unsigned char c[32];
+		__m128i v[2];
+	} d_branchtab27_sse2[2];
+
+	__m128i d_metric0[4] __attribute__ ((aligned(16)));
+	__m128i d_metric1[4] __attribute__ ((aligned(16)));
+	__m128i d_path0[4] __attribute__ ((aligned(16)));
+	__m128i d_path1[4] __attribute__ ((aligned(16)));
+
+	int d_ntraceback;
+	int d_k;
+	ofdm_param *d_ofdm;
+	frame_param *d_frame;
+	const unsigned char *d_depuncture_pattern;
+
+	uint8_t d_depunctured[MAX_ENCODED_BITS];
+	uint8_t d_decoded[MAX_ENCODED_BITS * 3 / 4];
+
+	static const unsigned char PARTAB[256];
+	static const unsigned char PUNCTURE_1_2[2];
+	static const unsigned char PUNCTURE_2_3[4];
+	static const unsigned char PUNCTURE_3_4[6];
+
+	void reset();
+	uint8_t* depuncture(uint8_t *in);
+
+	void viterbi_chunks_init_sse2();
+	void viterbi_butterfly2_sse2(unsigned char *symbols,
+			__m128i m0[], __m128i m1[], __m128i p0[], __m128i p1[]);
+	unsigned char viterbi_get_output_sse2(__m128i *mm0,
+			__m128i *pp0, int ntraceback, unsigned char *outbuf);
+};
+
+} // namespace ieee802_11
+} // namespace gr
+
+#endif /* INCLUDED_IEEE802_11_VITERBI_DECODER_X86_H */