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155 lines
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C

/**
* Copyright 2013-2021 Software Radio Systems Limited
*
* This file is part of srsRAN.
*
* srsRAN is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsRAN 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 Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include "srsran/config.h"
#define MAKE_CALL(a) CONCAT2(a, type_name)
#define MAKE_VEC(a) CONCAT2(a, vec_suffix)
#define PRINT CONCAT2(srsran_vec_fprint, print_suffix)
#ifdef LLR_IS_8BIT
#define llr_t int8_t
#define type_name _8bit
#define vec_suffix _bbb
#define print_suffix _bs
#define decptr h->dec8[h->current_dec]
#define dechdlr h->dec8_hdlr[h->current_dec]
#define input_is_interleaved 1
#else
#ifdef LLR_IS_16BIT
#define llr_t int16_t
#define vec_suffix _sss
#define print_suffix _s
#define decptr h->dec16[h->current_dec]
#define dechdlr h->dec16_hdlr[h->current_dec]
#define input_is_interleaved (h->current_dec > 0)
#define type_name _16bit
#else
#pragma message "Unsupported LLR mode"
#endif
#endif
#define debug_enabled_iter 0
#define debug_len 20
#define debug_vec(a) \
if (debug_enabled_iter) { \
printf("%s it=%d: ", STRING(a), n_iter); \
PRINT(stdout, a, debug_len); \
}
static void MAKE_CALL(
extract_input_tail_sb)(llr_t* input, llr_t* syst, llr_t* app2, llr_t* parity0, llr_t* parity1, uint32_t long_cb)
{
for (int i = long_cb; i < long_cb + 3; i++) {
syst[i] = input[3 * (long_cb + 32) + 2 * (i - long_cb)];
parity0[i] = input[3 * (long_cb + 32) + 2 * (i - long_cb) + 1];
app2[i] = input[3 * (long_cb + 32) + 6 + 2 * (i - long_cb)];
parity1[i] = input[3 * (long_cb + 32) + 6 + 2 * (i - long_cb) + 1];
}
}
/* Runs 1 turbo decoder iteration */
void MAKE_CALL(run_tdec_iteration)(srsran_tdec_t* h, llr_t* input)
{
if (h->current_cbidx >= 0) {
uint16_t* inter = h->interleaver[h->current_inter_idx][h->current_cbidx].forward;
uint16_t* deinter = h->interleaver[h->current_inter_idx][h->current_cbidx].reverse;
llr_t* syst = (llr_t*)h->syst0;
llr_t* parity0 = (llr_t*)h->parity0;
llr_t* parity1 = (llr_t*)h->parity1;
llr_t* app1 = (llr_t*)h->app1;
llr_t* app2 = (llr_t*)h->app2;
llr_t* ext1 = (llr_t*)h->ext1;
llr_t* ext2 = (llr_t*)h->ext2;
uint32_t long_cb = h->current_long_cb;
uint32_t n_iter = h->n_iter;
if (SRSRAN_TDEC_EXPECT_INPUT_SB && !h->force_not_sb && input_is_interleaved) {
syst = input;
// align to 32 bytes (warning: must be same alignment as in rm_turbo.c)
parity0 = &input[long_cb + 32];
parity1 = &input[2 * (long_cb + 32)];
if (n_iter == 0) {
MAKE_CALL(extract_input_tail_sb)(input, syst, app2, parity0, parity1, long_cb);
}
} else {
if (n_iter == 0) {
decptr->tdec_extract_input(input, syst, app2, parity0, parity1, long_cb);
}
}
if ((n_iter % 2) == 0) {
// Add apriori information to decoder 1
if (n_iter) {
MAKE_VEC(srsran_vec_sub)(app1, ext1, app1, long_cb);
}
// Run MAP DEC #1
decptr->tdec_dec(dechdlr, syst, n_iter ? app1 : NULL, parity0, ext1, long_cb);
}
// Interleave extrinsic output of DEC1 to form apriori info for decoder 2
if (n_iter % 2) {
// Convert aposteriori information into extrinsic information
if (n_iter > 1) {
MAKE_VEC(srsran_vec_sub)(ext1, app1, ext1, long_cb);
}
MAKE_VEC(srsran_vec_lut)(ext1, deinter, app2, long_cb);
// Run MAP DEC #2. 2nd decoder uses apriori information as systematic bits
decptr->tdec_dec(dechdlr, app2, NULL, parity1, ext2, long_cb);
// Deinterleaved extrinsic bits become apriori info for decoder 1
MAKE_VEC(srsran_vec_lut)(ext2, inter, app1, long_cb);
}
if (h->n_iter == 0) {
debug_vec(syst);
debug_vec(parity0);
debug_vec(parity1);
}
debug_vec(ext1);
debug_vec(ext2);
debug_vec(app1);
debug_vec(app2);
h->n_iter++;
} else {
ERROR("Error CB index not set (call srsran_tdec_new_cb() first");
}
}
#undef debug_enabled
#undef debug_len
#undef debug_vec
#undef llr_t
#undef vec_suffix
#undef print_suffix
#undef decptr
#undef dechdlr
#undef type_name
#undef input_is_interleaved