- Added new Viterbi convolutional decoder to the OFDM Decode Mac block replacing the former IT++ version. This new decoder uses
SSE2 and improves the performance significantly. The decoder was taken from the gr-dvbt module from GNU Radio. - Disabled some logging functions in the ofdm_mac and ofdm_decode_signal blocks that were degrading the performance significantly. [Gonzalo Arcos | Rodrigo Ferreri]
This commit is contained in:
Gonzalo Arcos
committed by
Bastian Bloessl
Bastian Bloessl
parent
74ae445143
commit
0f56254df3
+694
@@ -340,3 +340,697 @@ void generate_bits(const char *psdu, char *data_bits, tx_param &tx) {
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}
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}
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}
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/* Here starts the SSE2 Viterbi convolutional decoder implementation */
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/*
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* Copyright 1995 Phil Karn, KA9Q
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* Copyright 2008 Free Software Foundation, Inc.
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* 2014 Added SSE2 implementation Bogdan Diaconescu
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*
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* This file is part of GNU Radio
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*
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* GNU Radio 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, or (at your option)
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* any later version.
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*
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* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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/*
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* Viterbi decoder for K=7 rate=1/2 convolutional code
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* Some modifications from original Karn code by Matt Ettus
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* Major modifications by adding SSE2 code by Bogdan Diaconescu
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*/
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#include <xmmintrin.h>
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/* The two generator polynomials for the NASA Standard K=7 code.
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* Since these polynomials are known to be optimal for this constraint
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* length there is not much point in changing them. But if you do, you
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* will have to regenerate the BUTTERFLY macro calls in viterbi()
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*/
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#define POLYA 0x6d
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#define POLYB 0x4f
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/* The basic Viterbi decoder operation, called a "butterfly"
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* operation because of the way it looks on a trellis diagram. Each
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* butterfly involves an Add-Compare-Select (ACS) operation on the two nodes
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* where the 0 and 1 paths from the current node merge at the next step of
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* the trellis.
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*
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* The code polynomials are assumed to have 1's on both ends. Given a
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* function encode_state() that returns the two symbols for a given
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* encoder state in the low two bits, such a code will have the following
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* identities for even 'n' < 64:
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*
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* encode_state(n) = encode_state(n+65)
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* encode_state(n+1) = encode_state(n+64) = (3 ^ encode_state(n))
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*
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* Any convolutional code you would actually want to use will have
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* these properties, so these assumptions aren't too limiting.
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*
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* Doing this as a macro lets the compiler evaluate at compile time the
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* many expressions that depend on the loop index and encoder state and
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* emit them as immediate arguments.
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* This makes an enormous difference on register-starved machines such
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* as the Intel x86 family where evaluating these expressions at runtime
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* would spill over into memory.
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*/
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static union branchtab27 { unsigned char c[32]; __m128i v[2];} Branchtab27_sse2[2];
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// Maximum number of traceback bytes
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#define TRACEBACK_MAX 24
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// Metrics for each state
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static unsigned char mmresult[64] __attribute__((aligned(16))) = {0};
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// Paths for each state
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static unsigned char ppresult[TRACEBACK_MAX][64] __attribute__((aligned(16))) = {{0,0}};
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// Position in circular buffer where the current decoded byte is stored
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static int store_pos = 0;
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#define BUTTERFLY(i,sym) { \
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int m0,m1,m2,m3;\
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/* ACS for 0 branch */\
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m0 = state[i].metric + mets[sym]; /* 2*i */\
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m1 = state[i+32].metric + mets[3 ^ sym]; /* 2*i + 64 */\
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if(m0 > m1){\
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next[2*i].metric = m0;\
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next[2*i].path = state[i].path << 1;\
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} else {\
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next[2*i].metric = m1;\
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next[2*i].path = (state[i+32].path << 1)|1;\
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}\
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/* ACS for 1 branch */\
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m2 = state[i].metric + mets[3 ^ sym]; /* 2*i + 1 */\
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m3 = state[i+32].metric + mets[sym]; /* 2*i + 65 */\
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if(m2 > m3){\
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next[2*i+1].metric = m2;\
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next[2*i+1].path = state[i].path << 1;\
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} else {\
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next[2*i+1].metric = m3;\
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next[2*i+1].path = (state[i+32].path << 1)|1;\
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}\
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}
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unsigned char d_Partab[] = {
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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0, 1, 1, 0, 1, 0, 0, 1,
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0, 1, 1, 0, 1, 0, 0, 1,
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1, 0, 0, 1, 0, 1, 1, 0,
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};/* Parity lookup table */
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/* Convolutionally encode data into binary symbols */
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unsigned char
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d_encode(unsigned char *symbols,
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unsigned char *data,
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unsigned int nbytes,
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unsigned char encstate)
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{
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int i;
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while(nbytes-- != 0){
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for(i=7;i>=0;i--){
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encstate = (encstate << 1) | ((*data >> i) & 1);
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*symbols++ = d_Partab[encstate & POLYA];
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*symbols++ = d_Partab[encstate & POLYB];
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}
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data++;
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}
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return encstate;
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}
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/* Viterbi decoder */
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int
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d_viterbi(unsigned long *metric, /* Final path metric (returned value) */
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unsigned char *data, /* Decoded output data */
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unsigned char *symbols, /* Raw deinterleaved input symbols */
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unsigned int nbits, /* Number of output bits */
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int mettab[2][256] /* Metric table, [sent sym][rx symbol] */
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){
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unsigned int bitcnt = 0;
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int mets[4];
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long bestmetric;
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int beststate,i;
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struct viterbi_state state0[64],state1[64],*state,*next;
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state = state0;
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next = state1;
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/* Initialize starting metrics to prefer 0 state */
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state[0].metric = 0;
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for(i=1;i<64;i++)
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state[i].metric = -999999;
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state[0].path = 0;
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for(bitcnt = 0;bitcnt < nbits;bitcnt++){
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/* Read input symbol pair and compute all possible branch
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* metrics
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*/
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mets[0] = mettab[0][symbols[0]] + mettab[0][symbols[1]];
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mets[1] = mettab[0][symbols[0]] + mettab[1][symbols[1]];
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mets[2] = mettab[1][symbols[0]] + mettab[0][symbols[1]];
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mets[3] = mettab[1][symbols[0]] + mettab[1][symbols[1]];
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symbols += 2;
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BUTTERFLY(0,0); BUTTERFLY(1,1); BUTTERFLY(2,3); BUTTERFLY(3,2);
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BUTTERFLY(4,3); BUTTERFLY(5,2); BUTTERFLY(6,0); BUTTERFLY(7,1);
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BUTTERFLY(8,0); BUTTERFLY(9,1); BUTTERFLY(10,3); BUTTERFLY(11,2);
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BUTTERFLY(12,3); BUTTERFLY(13,2); BUTTERFLY(14,0); BUTTERFLY(15,1);
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BUTTERFLY(16,2); BUTTERFLY(17,3); BUTTERFLY(18,1); BUTTERFLY(19,0);
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BUTTERFLY(20,1); BUTTERFLY(21,0); BUTTERFLY(22,2); BUTTERFLY(23,3);
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BUTTERFLY(24,2); BUTTERFLY(25,3); BUTTERFLY(26,1); BUTTERFLY(27,0);
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BUTTERFLY(28,1); BUTTERFLY(29,0); BUTTERFLY(30,2); BUTTERFLY(31,3);
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/* Swap current and next states */
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if(bitcnt & 1){
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state = state0;
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next = state1;
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} else {
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state = state1;
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next = state0;
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}
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// ETTUS
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//if(bitcnt > nbits-7){
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/* In tail, poison non-zero nodes */
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//for(i=1;i<64;i += 2)
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// state[i].metric = -9999999;
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//}
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/* Produce output every 8 bits once path memory is full */
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if((bitcnt % 8) == 5 && bitcnt > 32){
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/* Find current best path */
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bestmetric = state[0].metric;
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beststate = 0;
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for(i=1;i<64;i++){
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if(state[i].metric > bestmetric){
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bestmetric = state[i].metric;
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beststate = i;
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}
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}
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#ifdef notdef
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printf("metrics[%d] = %d state = %lx\n",beststate,
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state[beststate].metric,state[beststate].path);
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#endif
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*data++ = state[beststate].path >> 24;
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}
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}
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/* Output remaining bits from 0 state */
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// ETTUS Find best state instead
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bestmetric = state[0].metric;
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beststate = 0;
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for(i=1;i<64;i++){
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if(state[i].metric > bestmetric){
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bestmetric = state[i].metric;
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beststate = i;
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}
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}
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if((i = bitcnt % 8) != 6)
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state[beststate].path <<= 6-i;
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*data++ = state[beststate].path >> 24;
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*data++ = state[beststate].path >> 16;
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*data++ = state[beststate].path >> 8;
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*data = state[beststate].path;
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//printf ("BS = %d\tBSM = %d\tM0 = %d\n",beststate,state[beststate].metric,state[0].metric);
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*metric = state[beststate].metric;
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return 0;
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}
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void
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d_viterbi_chunks_init(struct viterbi_state* state) {
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// Initialize starting metrics to prefer 0 state
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int i;
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state[0].metric = 0;
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state[0].path = 0;
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for(i=1;i<64;i++)
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{
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state[i].metric = 0;//-999999;
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state[i].path = 0;
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}
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}
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void
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d_viterbi_chunks_init_sse2(__m128i *mm0, __m128i *pp0) {
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// Initialize starting metrics to prefer 0 state
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int i, j;
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for (i = 0; i < 4; i++)
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{
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mm0[i] = _mm_setzero_si128();
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pp0[i] = _mm_setzero_si128();
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}
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int polys[2] = { POLYA, POLYB };
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for(i=0; i < 32; i++)
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{
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Branchtab27_sse2[0].c[i] = (polys[0] < 0) ^ d_Partab[(2*i) & abs(polys[0])] ? 1 : 0;
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Branchtab27_sse2[1].c[i] = (polys[1] < 0) ^ d_Partab[(2*i) & abs(polys[1])] ? 1 : 0;
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}
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for (i = 0; i < 64; i++)
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{
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mmresult[i] = 0;
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for (j = 0; j < TRACEBACK_MAX; j++)
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ppresult[j][i] = 0;
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}
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}
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void
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d_viterbi_butterfly8(unsigned char *symbols, int mettab[2][256], struct viterbi_state *state0, struct viterbi_state *state1)
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{
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unsigned int bitcnt;
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int mets[4];
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struct viterbi_state *state, *next;
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state = state0;
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next = state1;
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// Operate on 16 symbols (8 bits) at a time
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for(bitcnt = 0;bitcnt < 8;bitcnt++){
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// Read input symbol pair and compute all possible branch metrics
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mets[0] = mettab[0][symbols[0]] + mettab[0][symbols[1]];
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mets[1] = mettab[0][symbols[0]] + mettab[1][symbols[1]];
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mets[2] = mettab[1][symbols[0]] + mettab[0][symbols[1]];
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mets[3] = mettab[1][symbols[0]] + mettab[1][symbols[1]];
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symbols += 2;
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// These macro calls were generated by genbut.c
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BUTTERFLY(0,0); BUTTERFLY(1,1); BUTTERFLY(2,3); BUTTERFLY(3,2);
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BUTTERFLY(4,3); BUTTERFLY(5,2); BUTTERFLY(6,0); BUTTERFLY(7,1);
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BUTTERFLY(8,0); BUTTERFLY(9,1); BUTTERFLY(10,3); BUTTERFLY(11,2);
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BUTTERFLY(12,3); BUTTERFLY(13,2); BUTTERFLY(14,0); BUTTERFLY(15,1);
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BUTTERFLY(16,2); BUTTERFLY(17,3); BUTTERFLY(18,1); BUTTERFLY(19,0);
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BUTTERFLY(20,1); BUTTERFLY(21,0); BUTTERFLY(22,2); BUTTERFLY(23,3);
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BUTTERFLY(24,2); BUTTERFLY(25,3); BUTTERFLY(26,1); BUTTERFLY(27,0);
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BUTTERFLY(28,1); BUTTERFLY(29,0); BUTTERFLY(30,2); BUTTERFLY(31,3);
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// Swap current and next states
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if(bitcnt & 1){
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state = state0;
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next = state1;
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} else {
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state = state1;
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next = state0;
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}
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}
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}
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void
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d_viterbi_butterfly2(unsigned char *symbols, int mettab[2][256], struct viterbi_state *state0, struct viterbi_state *state1)
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{
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int mets[4];
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struct viterbi_state *state, *next;
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state = state0;
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next = state1;
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// Operate on 4 symbols (2 bits) at a time
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// Read input symbol pair and compute all possible branch metrics
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#if 0
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if (symbols[0] == 2)
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{
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mets[0] = mettab[0][symbols[1]];
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mets[1] = mettab[1][symbols[1]];
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mets[2] = mettab[0][symbols[1]];
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mets[3] = mettab[1][symbols[1]];
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}
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else if (symbols[1] == 2)
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{
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mets[0] = mettab[0][symbols[0]];
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mets[1] = mettab[1][symbols[0]];
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mets[2] = mettab[0][symbols[0]];
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mets[3] = mettab[1][symbols[0]];
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}
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else
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#endif
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{
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mets[0] = mettab[0][symbols[0]] + mettab[0][symbols[1]];
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mets[1] = mettab[0][symbols[0]] + mettab[1][symbols[1]];
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mets[2] = mettab[1][symbols[0]] + mettab[0][symbols[1]];
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mets[3] = mettab[1][symbols[0]] + mettab[1][symbols[1]];
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}
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// These macro calls were generated by genbut.c
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BUTTERFLY(0,0); BUTTERFLY(1,1); BUTTERFLY(2,3); BUTTERFLY(3,2);
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BUTTERFLY(4,3); BUTTERFLY(5,2); BUTTERFLY(6,0); BUTTERFLY(7,1);
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BUTTERFLY(8,0); BUTTERFLY(9,1); BUTTERFLY(10,3); BUTTERFLY(11,2);
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BUTTERFLY(12,3); BUTTERFLY(13,2); BUTTERFLY(14,0); BUTTERFLY(15,1);
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BUTTERFLY(16,2); BUTTERFLY(17,3); BUTTERFLY(18,1); BUTTERFLY(19,0);
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BUTTERFLY(20,1); BUTTERFLY(21,0); BUTTERFLY(22,2); BUTTERFLY(23,3);
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BUTTERFLY(24,2); BUTTERFLY(25,3); BUTTERFLY(26,1); BUTTERFLY(27,0);
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BUTTERFLY(28,1); BUTTERFLY(29,0); BUTTERFLY(30,2); BUTTERFLY(31,3);
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state = state1;
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next = state0;
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// Read input symbol pair and compute all possible branch metrics
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#if 0
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if (symbols[2] == 2)
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{
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mets[0] = mettab[0][symbols[3]];
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mets[1] = mettab[1][symbols[3]];
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mets[2] = mettab[0][symbols[3]];
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mets[3] = mettab[1][symbols[3]];
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}
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else if (symbols[3] == 2)
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{
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mets[0] = mettab[0][symbols[2]];
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mets[1] = mettab[1][symbols[2]];
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mets[2] = mettab[0][symbols[2]];
|
||||
mets[3] = mettab[1][symbols[2]];
|
||||
}
|
||||
else
|
||||
#endif
|
||||
{
|
||||
mets[0] = mettab[0][symbols[2]] + mettab[0][symbols[3]];
|
||||
mets[1] = mettab[0][symbols[2]] + mettab[1][symbols[3]];
|
||||
mets[2] = mettab[1][symbols[2]] + mettab[0][symbols[3]];
|
||||
mets[3] = mettab[1][symbols[2]] + mettab[1][symbols[3]];
|
||||
}
|
||||
|
||||
// These macro calls were generated by genbut.c
|
||||
BUTTERFLY(0,0); BUTTERFLY(1,1); BUTTERFLY(2,3); BUTTERFLY(3,2);
|
||||
BUTTERFLY(4,3); BUTTERFLY(5,2); BUTTERFLY(6,0); BUTTERFLY(7,1);
|
||||
BUTTERFLY(8,0); BUTTERFLY(9,1); BUTTERFLY(10,3); BUTTERFLY(11,2);
|
||||
BUTTERFLY(12,3); BUTTERFLY(13,2); BUTTERFLY(14,0); BUTTERFLY(15,1);
|
||||
BUTTERFLY(16,2); BUTTERFLY(17,3); BUTTERFLY(18,1); BUTTERFLY(19,0);
|
||||
BUTTERFLY(20,1); BUTTERFLY(21,0); BUTTERFLY(22,2); BUTTERFLY(23,3);
|
||||
BUTTERFLY(24,2); BUTTERFLY(25,3); BUTTERFLY(26,1); BUTTERFLY(27,0);
|
||||
BUTTERFLY(28,1); BUTTERFLY(29,0); BUTTERFLY(30,2); BUTTERFLY(31,3);
|
||||
}
|
||||
|
||||
void
|
||||
d_viterbi_butterfly2_sse2(unsigned char *symbols, __m128i *mm0, __m128i *mm1, __m128i *pp0, __m128i *pp1)
|
||||
{
|
||||
int i;
|
||||
|
||||
__m128i *metric0, *metric1;
|
||||
__m128i *path0, *path1;
|
||||
|
||||
metric0 = mm0;
|
||||
path0 = pp0;
|
||||
metric1 = mm1;
|
||||
path1 = pp1;
|
||||
|
||||
// Operate on 4 symbols (2 bits) at a time
|
||||
|
||||
__m128i m0, m1, m2, m3, decision0, decision1, survivor0, survivor1;
|
||||
__m128i metsv, metsvm;
|
||||
__m128i shift0, shift1;
|
||||
__m128i tmp0, tmp1;
|
||||
__m128i sym0v, sym1v;
|
||||
|
||||
sym0v = _mm_set1_epi8(symbols[0]);
|
||||
sym1v = _mm_set1_epi8(symbols[1]);
|
||||
|
||||
for (i = 0; i < 2; i++)
|
||||
{
|
||||
if (symbols[0] == 2)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v);
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(1),metsvm);
|
||||
}
|
||||
else if (symbols[1] == 2)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v);
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(1),metsvm);
|
||||
}
|
||||
else
|
||||
{
|
||||
metsvm = _mm_add_epi8(_mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v),_mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v));
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(2),metsvm);
|
||||
}
|
||||
|
||||
m0 = _mm_add_epi8(metric0[i], metsv);
|
||||
m1 = _mm_add_epi8(metric0[i+2], metsvm);
|
||||
m2 = _mm_add_epi8(metric0[i], metsvm);
|
||||
m3 = _mm_add_epi8(metric0[i+2], metsv);
|
||||
|
||||
decision0 = _mm_cmpgt_epi8(_mm_sub_epi8(m0,m1),_mm_setzero_si128());
|
||||
decision1 = _mm_cmpgt_epi8(_mm_sub_epi8(m2,m3),_mm_setzero_si128());
|
||||
survivor0 = _mm_or_si128(_mm_and_si128(decision0,m0),_mm_andnot_si128(decision0,m1));
|
||||
survivor1 = _mm_or_si128(_mm_and_si128(decision1,m2),_mm_andnot_si128(decision1,m3));
|
||||
|
||||
shift0 = _mm_slli_epi16(path0[i], 1);
|
||||
shift1 = _mm_slli_epi16(path0[2+i], 1);
|
||||
shift1 = _mm_add_epi8(shift1, _mm_set1_epi8(1));
|
||||
|
||||
metric1[2*i] = _mm_unpacklo_epi8(survivor0,survivor1);
|
||||
tmp0 = _mm_or_si128(_mm_and_si128(decision0,shift0),_mm_andnot_si128(decision0,shift1));
|
||||
|
||||
metric1[2*i+1] = _mm_unpackhi_epi8(survivor0,survivor1);
|
||||
tmp1 = _mm_or_si128(_mm_and_si128(decision1,shift0),_mm_andnot_si128(decision1,shift1));
|
||||
|
||||
path1[2*i] = _mm_unpacklo_epi8(tmp0, tmp1);
|
||||
path1[2*i+1] = _mm_unpackhi_epi8(tmp0, tmp1);
|
||||
}
|
||||
|
||||
metric0 = mm1;
|
||||
path0 = pp1;
|
||||
metric1 = mm0;
|
||||
path1 = pp0;
|
||||
|
||||
sym0v = _mm_set1_epi8(symbols[2]);
|
||||
sym1v = _mm_set1_epi8(symbols[3]);
|
||||
|
||||
for (i = 0; i < 2; i++)
|
||||
{
|
||||
if (symbols[2] == 2)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v);
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(1),metsvm);
|
||||
}
|
||||
else if (symbols[3] == 2)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v);
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(1),metsvm);
|
||||
}
|
||||
else
|
||||
{
|
||||
metsvm = _mm_add_epi8(_mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v),_mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v));
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(2),metsvm);
|
||||
}
|
||||
|
||||
m0 = _mm_add_epi8(metric0[i], metsv);
|
||||
m1 = _mm_add_epi8(metric0[i+2], metsvm);
|
||||
m2 = _mm_add_epi8(metric0[i], metsvm);
|
||||
m3 = _mm_add_epi8(metric0[i+2], metsv);
|
||||
|
||||
decision0 = _mm_cmpgt_epi8(_mm_sub_epi8(m0,m1),_mm_setzero_si128());
|
||||
decision1 = _mm_cmpgt_epi8(_mm_sub_epi8(m2,m3),_mm_setzero_si128());
|
||||
survivor0 = _mm_or_si128(_mm_and_si128(decision0,m0),_mm_andnot_si128(decision0,m1));
|
||||
survivor1 = _mm_or_si128(_mm_and_si128(decision1,m2),_mm_andnot_si128(decision1,m3));
|
||||
|
||||
shift0 = _mm_slli_epi16(path0[i], 1);
|
||||
shift1 = _mm_slli_epi16(path0[2+i], 1);
|
||||
shift1 = _mm_add_epi8(shift1, _mm_set1_epi8(1));
|
||||
|
||||
metric1[2*i] = _mm_unpacklo_epi8(survivor0,survivor1);
|
||||
tmp0 = _mm_or_si128(_mm_and_si128(decision0,shift0),_mm_andnot_si128(decision0,shift1));
|
||||
|
||||
metric1[2*i+1] = _mm_unpackhi_epi8(survivor0,survivor1);
|
||||
tmp1 = _mm_or_si128(_mm_and_si128(decision1,shift0),_mm_andnot_si128(decision1,shift1));
|
||||
|
||||
path1[2*i] = _mm_unpacklo_epi8(tmp0, tmp1);
|
||||
path1[2*i+1] = _mm_unpackhi_epi8(tmp0, tmp1);
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
d_viterbi_butterfly_sse2(unsigned char *symbols, __m128i *mm0, __m128i *mm1, __m128i *pp0, __m128i *pp1)
|
||||
{
|
||||
int i;
|
||||
|
||||
__m128i *metric0, *metric1;
|
||||
__m128i *path0, *path1;
|
||||
|
||||
metric0 = mm0;
|
||||
path0 = pp0;
|
||||
metric1 = mm1;
|
||||
path1 = pp1;
|
||||
|
||||
for (i = 0; i < 2; i++)
|
||||
printf("symbols[%i]: %i\n", i, symbols[i]);
|
||||
|
||||
|
||||
// Operate on 4 symbols (2 bits) at a time
|
||||
|
||||
__m128i m0, m1, m2, m3, decision0, decision1, survivor0, survivor1;
|
||||
__m128i metsv, metsvm;
|
||||
__m128i shift0, shift1;
|
||||
__m128i tmp0, tmp1;
|
||||
__m128i sym0v, sym1v;
|
||||
|
||||
sym0v = _mm_set1_epi8(symbols[0]);
|
||||
sym1v = _mm_set1_epi8(symbols[1]);
|
||||
|
||||
for (i = 0; i < 2; i++)
|
||||
{
|
||||
#if 1
|
||||
if (symbols[0] == 2)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v);
|
||||
}
|
||||
else if (symbols[1] == 0)
|
||||
{
|
||||
metsvm = _mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v);
|
||||
}
|
||||
else
|
||||
#endif
|
||||
metsvm = _mm_add_epi8(_mm_xor_si128(Branchtab27_sse2[0].v[i],sym0v),_mm_xor_si128(Branchtab27_sse2[1].v[i],sym1v));
|
||||
|
||||
metsv = _mm_sub_epi8(_mm_set1_epi8(2),metsvm);
|
||||
|
||||
m0 = _mm_add_epi8(metric0[i], metsv);
|
||||
m1 = _mm_add_epi8(metric0[i+2], metsvm);
|
||||
m2 = _mm_add_epi8(metric0[i], metsvm);
|
||||
m3 = _mm_add_epi8(metric0[i+2], metsv);
|
||||
|
||||
decision0 = _mm_cmpgt_epi8(_mm_sub_epi8(m0,m1),_mm_setzero_si128());
|
||||
decision1 = _mm_cmpgt_epi8(_mm_sub_epi8(m2,m3),_mm_setzero_si128());
|
||||
survivor0 = _mm_or_si128(_mm_and_si128(decision0,m0),_mm_andnot_si128(decision0,m1));
|
||||
survivor1 = _mm_or_si128(_mm_and_si128(decision1,m2),_mm_andnot_si128(decision1,m3));
|
||||
|
||||
shift0 = _mm_slli_epi16(path0[i], 1);
|
||||
shift1 = _mm_slli_epi16(path0[2+i], 1);
|
||||
shift1 = _mm_add_epi8(shift1, _mm_set1_epi8(1));
|
||||
|
||||
metric1[2*i] = _mm_unpacklo_epi8(survivor0,survivor1);
|
||||
tmp0 = _mm_or_si128(_mm_and_si128(decision0,shift0),_mm_andnot_si128(decision0,shift1));
|
||||
|
||||
metric1[2*i+1] = _mm_unpackhi_epi8(survivor0,survivor1);
|
||||
tmp1 = _mm_or_si128(_mm_and_si128(decision1,shift0),_mm_andnot_si128(decision1,shift1));
|
||||
|
||||
path1[2*i] = _mm_unpacklo_epi8(tmp0, tmp1);
|
||||
path1[2*i+1] = _mm_unpackhi_epi8(tmp0, tmp1);
|
||||
}
|
||||
|
||||
for (i = 0; i < 4; i++)
|
||||
{
|
||||
mm0[i] = metric1[i];
|
||||
pp0[i] = path1[i];
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
|
||||
unsigned char
|
||||
d_viterbi_get_output(struct viterbi_state *state, unsigned char *outbuf) {
|
||||
// Produce output every 8 bits once path memory is full
|
||||
// if((bitcnt % 8) == 5 && bitcnt > 32) {
|
||||
|
||||
// Find current best path
|
||||
unsigned int i, beststate = 0;
|
||||
int bestmetric;
|
||||
|
||||
bestmetric = state[0].metric;
|
||||
beststate = 0;
|
||||
for(i=1;i<64;i++)
|
||||
{
|
||||
if(state[i].metric > bestmetric) {
|
||||
bestmetric = state[i].metric;
|
||||
beststate = i;
|
||||
}
|
||||
}
|
||||
|
||||
*outbuf = state[beststate].path >> 24;
|
||||
|
||||
return bestmetric;
|
||||
}
|
||||
|
||||
unsigned char
|
||||
d_viterbi_get_output_sse2(__m128i *mm0, __m128i *pp0, int ntraceback, unsigned char *outbuf) {
|
||||
// Find current best path
|
||||
int i;
|
||||
int bestmetric, minmetric;
|
||||
int beststate = 0;
|
||||
int pos = 0;
|
||||
|
||||
// Implement a circular buffer with the last ntraceback paths
|
||||
store_pos = (store_pos + 1) % ntraceback;
|
||||
|
||||
// TODO - find another way to extract the value
|
||||
for (i = 0; i < 4; i++)
|
||||
{
|
||||
_mm_store_si128((__m128i *) &mmresult[i*16], mm0[i]);
|
||||
_mm_store_si128((__m128i *) &ppresult[store_pos][i*16], pp0[i]);
|
||||
}
|
||||
|
||||
// Find out the best final state
|
||||
bestmetric = mmresult[beststate];
|
||||
minmetric = mmresult[beststate];
|
||||
|
||||
for (i = 1; i < 64; i++)
|
||||
{
|
||||
if (mmresult[i] > bestmetric)
|
||||
{
|
||||
bestmetric = mmresult[i];
|
||||
beststate = i;
|
||||
}
|
||||
if (mmresult[i] < minmetric)
|
||||
minmetric = mmresult[i];
|
||||
}
|
||||
|
||||
// Trace back
|
||||
for (i = 0, pos = store_pos; i < (ntraceback - 1); i++)
|
||||
{
|
||||
// Obtain the state from the output bits
|
||||
// by clocking in the output bits in reverse order.
|
||||
// The state has only 6 bits
|
||||
beststate = ppresult[pos][beststate] >> 2;
|
||||
pos = (pos - 1 + ntraceback) % ntraceback;
|
||||
}
|
||||
|
||||
// Store output byte
|
||||
*outbuf = ppresult[pos][beststate];
|
||||
|
||||
// Zero out the path variable
|
||||
// and prevent metric overflow
|
||||
for (i = 0; i < 4; i++)
|
||||
{
|
||||
pp0[i] = _mm_setzero_si128();
|
||||
mm0[i] = _mm_sub_epi8(mm0[i], _mm_set1_epi8(minmetric));
|
||||
}
|
||||
|
||||
return bestmetric;
|
||||
}
|
||||
/* end of new functions */
|
||||
|
||||
Reference in New Issue
Block a user