Stephen Wolfe
c6502ae022
Add generic version of viterbi decoder that does not utilize x86 intrinsics to provide support for other architectures such as ARM.
115 lines
3.4 KiB
C++
115 lines
3.4 KiB
C++
/*
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* Copyright (C) 2016 Bastian Bloessl <bloessl@ccs-labs.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_IEEE802_11_VITERBI_DECODER_H
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#define INCLUDED_IEEE802_11_VITERBI_DECODER_H
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#ifdef IEEE80211_MSSE2
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#include <xmmintrin.h>
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#endif
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#include "utils.h"
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namespace gr {
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namespace ieee802_11 {
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// Maximum number of traceback bytes
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#define TRACEBACK_MAX 24
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/* This Viterbi decoder was taken from the gr-dvbt module of
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* GNU Radio. It is an SSE2 version of the Viterbi Decoder
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* created by Phil Karn. The SSE2 version was made by Bogdan
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* Diaconescu. For more info see: gr-dvbt/lib/d_viterbi.h
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*/
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class viterbi_decoder
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{
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public:
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viterbi_decoder();
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virtual ~viterbi_decoder();
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uint8_t* decode(ofdm_param *ofdm, frame_param *frame, uint8_t *in);
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private:
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// Position in circular buffer where the current decoded byte is stored
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int d_store_pos;
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// Metrics for each state
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unsigned char d_mmresult[64] __attribute__((aligned(16)));
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// Paths for each state
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unsigned char d_ppresult[TRACEBACK_MAX][64] __attribute__((aligned(16)));
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#ifdef IEEE80211_MSSE2
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union branchtab27 {
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unsigned char c[32];
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__m128i v[2];
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} d_branchtab27_sse2[2];
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#else
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union branchtab27 {
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unsigned char c[32];
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} d_branchtab27_generic[2];
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#endif
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#ifdef IEEE80211_MSSE2
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__m128i d_metric0[4] __attribute__ ((aligned(16)));
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__m128i d_metric1[4] __attribute__ ((aligned(16)));
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__m128i d_path0[4] __attribute__ ((aligned(16)));
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__m128i d_path1[4] __attribute__ ((aligned(16)));
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#else
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unsigned char d_metric0_generic[64] __attribute__ ((aligned(16)));
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unsigned char d_metric1_generic[64] __attribute__ ((aligned(16)));
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unsigned char d_path0_generic[64] __attribute__ ((aligned(16)));
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unsigned char d_path1_generic[64] __attribute__ ((aligned(16)));
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#endif
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int d_ntraceback;
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int d_k;
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ofdm_param *d_ofdm;
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frame_param *d_frame;
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const unsigned char *d_depuncture_pattern;
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uint8_t d_depunctured[MAX_ENCODED_BITS];
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uint8_t d_decoded[MAX_ENCODED_BITS * 3 / 4];
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static const unsigned char PARTAB[256];
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static const unsigned char PUNCTURE_1_2[2];
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static const unsigned char PUNCTURE_2_3[4];
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static const unsigned char PUNCTURE_3_4[6];
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void reset();
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uint8_t* depuncture(uint8_t *in);
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#ifdef IEEE80211_MSSE2
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void viterbi_chunks_init_sse2();
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void viterbi_butterfly2_sse2(unsigned char *symbols,
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__m128i m0[], __m128i m1[], __m128i p0[], __m128i p1[]);
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unsigned char viterbi_get_output_sse2(__m128i *mm0,
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__m128i *pp0, int ntraceback, unsigned char *outbuf);
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#else
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void viterbi_chunks_init_generic();
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void viterbi_butterfly2_generic(unsigned char *symbols,
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unsigned char m0[], unsigned char m1[], unsigned char p0[],
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unsigned char p1[]);
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unsigned char viterbi_get_output_generic(unsigned char *mm0,
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unsigned char *pp0, int ntraceback, unsigned char *outbuf);
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#endif
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};
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} // namespace ieee802_11
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} // namespace gr
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#endif /* INCLUDED_IEEE802_11_VITERBI_DECODER_H */
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