1 files changed, 140 insertions, 0 deletions
diff --git a/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc
new file mode 100644
index 0000000000..8e9cbc02b7
--- /dev/null
+++ b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc
@@ -0,0 +1,140 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2014 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio 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, or (at your option)
+ * any later version.
+ *
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/io_signature.h>
+#include "atsc_viterbi_decoder_impl.h"
+#include "atsc_types.h"
+#include <atsc_viterbi_mux.cc> // machine generated
+#include <emmintrin.h>
+
+namespace gr {
+  namespace dtv {
+
+    atsc_viterbi_decoder::sptr
+    atsc_viterbi_decoder::make()
+    {
+      return gnuradio::get_initial_sptr
+	(new atsc_viterbi_decoder_impl());
+    }
+
+    atsc_viterbi_decoder_impl::atsc_viterbi_decoder_impl()
+      : sync_block("dtv_atsc_viterbi_decoder",
+                   io_signature::make(1, 1, sizeof(atsc_soft_data_segment)),
+                   io_signature::make(1, 1, sizeof(atsc_mpeg_packet_rs_encoded)))
+    {
+      set_output_multiple(NCODERS);
+
+      /*
+       * These fifo's handle the alignment problem caused by the
+       * inherent decoding delay of the individual viterbi decoders.
+       * The net result is that this entire block has a pipeline latency
+       * of 12 complete segments.
+       *
+       * If anybody cares, it is possible to do it with less delay, but
+       * this approach is at least somewhat understandable...
+       */
+
+      // the -4 is for the 4 sync symbols
+      int fifo_size = ATSC_DATA_SEGMENT_LENGTH - 4 - viterbi[0].delay();
+      for (int i = 0; i < NCODERS; i++)
+        fifo[i] = new fifo_t(fifo_size);
+
+      reset();
+    }
+
+    atsc_viterbi_decoder_impl::~atsc_viterbi_decoder_impl()
+    {
+      for (int i = 0; i < NCODERS; i++)
+        delete fifo[i];
+    }
+
+    void
+    atsc_viterbi_decoder_impl::reset()
+    {
+      for (int i = 0; i < NCODERS; i++)
+        fifo[i]->reset();
+    }
+
+    int
+    atsc_viterbi_decoder_impl::work(int noutput_items,
+                                    gr_vector_const_void_star &input_items,
+                                    gr_vector_void_star &output_items)
+    {
+      const atsc_soft_data_segment *in = (const atsc_soft_data_segment *) input_items[0];
+      atsc_mpeg_packet_rs_encoded *out = (atsc_mpeg_packet_rs_encoded *) output_items[0];
+
+      // The way the fs_checker works ensures we start getting packets
+      // starting with a field sync, and out input multiple is set to
+      // 12, so we should always get a mod 12 numbered first packet
+      assert(noutput_items % NCODERS == 0);
+
+      int dbwhere;
+      int dbindex;
+      int shift;
+      float symbols[NCODERS][enco_which_max];
+      unsigned char dibits[NCODERS][enco_which_max];
+
+      unsigned char out_copy[OUTPUT_SIZE];
+
+      for (int i = 0; i < noutput_items; i += NCODERS) {
+        /* Build a continuous symbol buffer for each encoder */
+        for (unsigned int encoder = 0; encoder < NCODERS; encoder++)
+          for (unsigned int k = 0; k < enco_which_max; k++)
+            symbols[encoder][k] = in[i + (enco_which_syms[encoder][k]/832)].data[enco_which_syms[encoder][k] % 832];
+
+        /* Now run each of the 12 Viterbi decoders over their subset of
+           the input symbols */
+        for (unsigned int encoder = 0; encoder < NCODERS; encoder++)
+          for (unsigned int k = 0; k < enco_which_max; k++)
+            dibits[encoder][k] = viterbi[encoder].decode(symbols[encoder][k]);
+
+        /* Move dibits into their location in the output buffer */
+        for (unsigned int encoder = 0; encoder < NCODERS; encoder++) {
+          for (unsigned int k = 0; k < enco_which_max; k++) {
+            /* Store the dibit into the output data segment */
+            dbwhere = enco_which_dibits[encoder][k];
+            dbindex = dbwhere >> 3;
+            shift = dbwhere & 0x7;
+            out_copy[dbindex] = (out_copy[dbindex] & ~(0x03 << shift)) | (fifo[encoder]->stuff(dibits[encoder][k]) << shift);
+          } /* Symbols fed into one encoder */
+        } /* Encoders */
+
+        // copy output from contiguous temp buffer into final output
+        for (int j = 0; j < NCODERS; j++) {
+          memcpy (&out[i + j].data[0],
+                  &out_copy[j * OUTPUT_SIZE/NCODERS],
+                  ATSC_MPEG_RS_ENCODED_LENGTH * sizeof(out_copy[0]));
+
+          // adjust pipeline info to reflect 12 segment delay
+          plinfo::delay(out[i + j].pli, in[i + j].pli, NCODERS);
+        }
+      }
+
+      return noutput_items;
+    }
+
+  } /* namespace dtv */
+} /* namespace gr */