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replaced Fisher-Yates shuffle with XorShiftMask mapping

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Ahmet Inan 2025-06-25 12:35:32 +02:00
commit 4cb15194aa
2 changed files with 40 additions and 38 deletions
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39
encode.cc
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@ -9,7 +9,6 @@ Copyright 2021 Ahmet Inan <inan@aicodix.de>
#include <cmath>
#include "xorshift.hh"
#include "complex.hh"
#include "permute.hh"
#include "utils.hh"
#include "bitman.hh"
#include "decibel.hh"
@ -45,11 +44,8 @@ struct Encoder
CODE::CRC<uint32_t> crc1;
CODE::BoseChaudhuriHocquenghemEncoder<255, 71> bchenc;
CODE::PolarEncoder<code_type> polarenc;
CODE::FisherYatesShuffle<4096> shuffle_4096;
CODE::FisherYatesShuffle<8192> shuffle_8192;
CODE::FisherYatesShuffle<16384> shuffle_16384;
uint8_t input_data[data_max];
code_type code[bits_max], mesg[bits_max];
code_type code[bits_max], perm[bits_max], mesg[bits_max];
cmplx fdom[symbol_len];
cmplx tdom[symbol_len];
cmplx temp[symbol_len];
@ -226,18 +222,23 @@ struct Encoder
}
return 2;
}
void shuffle(code_type *c)
void shuffle(code_type *dest, const code_type *src)
{
switch (code_order) {
case 12:
shuffle_4096(c);
break;
case 13:
shuffle_8192(c);
break;
case 14:
shuffle_16384(c);
break;
if (code_order == 12) {
CODE::XorShiftMask<int, 12, 1, 1, 4, 1> seq;
dest[0] = src[0];
for (int i = 1; i < 4096; ++i)
dest[i] = src[seq()];
} else if (code_order == 13) {
CODE::XorShiftMask<int, 13, 1, 1, 9, 1> seq;
dest[0] = src[0];
for (int i = 1; i < 8192; ++i)
dest[i] = src[seq()];
} else if (code_order == 14) {
CODE::XorShiftMask<int, 14, 1, 5, 10, 1> seq;
dest[0] = src[0];
for (int i = 1; i < 16384; ++i)
dest[i] = src[seq()];
}
}
Encoder(DSP::WritePCM<value> *pcm, const char *const *input_names, int input_count, int freq_off, uint64_t call_sign, int oper_mode) :
@ -393,21 +394,21 @@ struct Encoder
for (int i = 0; i < 32; ++i)
mesg[i+data_bits] = nrz((crc1()>>i)&1);
polarenc(code, mesg, frozen_bits, code_order);
shuffle(code);
shuffle(perm, code);
for (int i = 0; i < cons_cols; ++i)
prev[i] = fdom[bin(i+code_off)];
CODE::MLS seq0(mls0_poly);
for (int j = 0, k = 0; j < cons_rows; ++j) {
for (int i = 0; i < cons_cols; ++i) {
if (oper_mode < 26) {
prev[i] *= mod_map(code+k);
prev[i] *= mod_map(perm+k);
fdom[bin(i+code_off)] = prev[i];
k += mod_bits;
} else if (i % comb_dist == comb_off) {
prev[i] *= nrz(seq0());
fdom[bin(i+code_off)] = prev[i];
} else {
fdom[bin(i+code_off)] = prev[i] * mod_map(code+k);
fdom[bin(i+code_off)] = prev[i] * mod_map(perm+k);
k += mod_bits;
}
}