Files
dsd-fme/src/ez.cpp
2023-10-28 17:11:43 -04:00

344 lines
8.9 KiB
C++

/*-------------------------------------------------------------------------------
* ez.cpp
* EZPWD R-S bridge and ISCH map lookup
*
* original copyrights for portions used below (OP25, EZPWD)
*
* LWVMOBILE
* 2022-09 DSD-FME Florida Man Edition
*-----------------------------------------------------------------------------*/
#include "dsd.h"
#include "ezpwd/rs"
#include <map>
std::vector<uint8_t> ESS_A(28,0); // ESS_A and ESS_B are hexbits vectors
std::vector<uint8_t> ESS_B(16,0);
ezpwd::RS<63,35> rs28;
std::vector<uint8_t> HB(63,0);
std::vector<uint8_t> HBS(63,0);
std::vector<uint8_t> HBL(63,0);
std::vector<int> Erasures;
//Reed-Solomon Correction of ESS section
int ez_rs28_ess (int payload[96], int parity[168])
{
//do something
uint8_t a, b, i, j, k;
k = 0;
for (i = 0; i < 16; i++)
{
b = 0;
for (j = 0; j < 6; j++)
{
b = b << 1;
b = b + payload[k]; //convert bits to hexbits.
k++;
}
ESS_B[i] = b;
// fprintf (stderr, " %X", ESS_B[i]);
}
k = 0;
for (i = 0; i < 28; i++)
{
a = 0;
for (j = 0; j < 6; j++)
{
a = a << 1;
a = a + parity[k]; //convert bits to hexbits.
k++;
}
ESS_A[i] = a;
// fprintf (stderr, " %X ", ESS_A[i]);
}
int ec;
ec = rs28.decode (ESS_B, ESS_A);
// fprintf (stderr, "\n EC = %d \n", ec);
//convert ESS_B back to bits
k = 0;
for (i = 0; i < 16; i++)
{
b = 0;
for (j = 0; j < 6; j++)
{
b = (ESS_B[i] >> (5-j) & 0x1);
payload[k] = b;
k++;
}
// fprintf (stderr, " %X", ESS_B[i]);
}
return(ec);
}
//Reed-Solomon Correction of FACCH section
int ez_rs28_facch (int payload[156], int parity[114])
{
//do something!
int ec = -2;
int i, j, k, b;
//init HB
for (i = 0; i < 64; i++)
{
HB[i] = 0;
}
//Erasures for FACCH
Erasures = {0,1,2,3,4,5,6,7,8,54,55,56,57,58,59,60,61,62};
//convert bits to hexbits, 156 for payload, 114 parity
j = 9; //starting position according to OP25
for (i = 0; i < 156; i += 6)
{
HB[j] = (payload[i] << 5) + (payload[i+1] << 4) + (payload[i+2] << 3) + (payload[i+3] << 2) + (payload[i+4] << 1) + payload[i+5];
j++;
}
//j should continue from its last increment
for (i = 0; i < 114; i += 6)
{
HB[j] = (parity[i] << 5) + (parity[i+1] << 4) + (parity[i+2] << 3) + (parity[i+3] << 2) + (parity[i+4] << 1) + parity[i+5];
j++;
}
ec = rs28.decode(HB, Erasures);
//convert HB back to bits
//fprintf (stderr, "\n");
k = 0;
for (i = 0; i < 26; i++) //26*6=156 bits
{
b = 0;
for (j = 0; j < 6; j++)
{
b = (HB[i+9] >> (5-j) & 0x1); //+9 to mach our starting position
payload[k] = b;
//fprintf (stderr, "%d", payload[k]);
k++;
}
}
return (ec);
}
//Reed-Solomon Correction of SACCH section
int ez_rs28_sacch (int payload[180], int parity[132])
{
//do something!
int ec = -2;
int i, j, k, b;
//init HBS
for (i = 0; i < 64; i++)
{
HBS[i] = 0;
}
//Erasures for SACCH
Erasures = {0,1,2,3,4,57,58,59,60,61,62};
//convert bits to hexbits, 156 for payload, 114 parity
j = 5; //starting position according to OP25
for (i = 0; i < 180; i += 6)
{
HBS[j] = (payload[i] << 5) + (payload[i+1] << 4) + (payload[i+2] << 3) + (payload[i+3] << 2) + (payload[i+4] << 1) + payload[i+5];
j++;
}
//j should continue from its last increment
for (i = 0; i < 132; i += 6)
{
HBS[j] = (parity[i] << 5) + (parity[i+1] << 4) + (parity[i+2] << 3) + (parity[i+3] << 2) + (parity[i+4] << 1) + parity[i+5];
j++;
}
ec = rs28.decode(HBS, Erasures);
//convert HBS back to bits
// fprintf (stderr, "\n");
k = 0;
for (i = 0; i < 30; i++) //30*6=180 bits
{
b = 0;
for (j = 0; j < 6; j++)
{
b = (HBS[i+5] >> (5-j) & 0x1); //+5 to mach our starting position
payload[k] = b;
// fprintf (stderr, "%d", payload[k]);
k++;
}
}
return (ec);
}
//std::map <std::uint64_t, int> isch_map;
std::map <uint64_t, int> isch_map; //User Noted GCC potential compiler error fix on BB OP25
void map_isch()
{
isch_map[0x184229d461ULL] = 0;
isch_map[0x18761451f6ULL] = 1;
isch_map[0x181ae27e2fULL] = 2;
isch_map[0x182edffbb8ULL] = 3;
isch_map[0x18df8a7510ULL] = 4;
isch_map[0x18ebb7f087ULL] = 5;
isch_map[0x188741df5eULL] = 6;
isch_map[0x18b37c5ac9ULL] = 7;
isch_map[0x1146a44f13ULL] = 8;
isch_map[0x117299ca84ULL] = 9;
isch_map[0x111e6fe55dULL] = 10;
isch_map[0x112a5260caULL] = 11;
isch_map[0x11db07ee62ULL] = 12;
isch_map[0x11ef3a6bf5ULL] = 13;
isch_map[0x1183cc442cULL] = 14;
isch_map[0x11b7f1c1bbULL] = 15;
isch_map[0x1a4a2e239eULL] = 16;
isch_map[0x1a7e13a609ULL] = 17;
isch_map[0x1a12e589d0ULL] = 18;
isch_map[0x1a26d80c47ULL] = 19;
isch_map[0x1ad78d82efULL] = 20;
isch_map[0x1ae3b00778ULL] = 21;
isch_map[0x1a8f4628a1ULL] = 22;
isch_map[0x1abb7bad36ULL] = 23;
isch_map[0x134ea3b8ecULL] = 24;
isch_map[0x137a9e3d7bULL] = 25;
isch_map[0x13166812a2ULL] = 26;
isch_map[0x1322559735ULL] = 27;
isch_map[0x13d300199dULL] = 28;
isch_map[0x13e73d9c0aULL] = 29;
isch_map[0x138bcbb3d3ULL] = 30;
isch_map[0x13bff63644ULL] = 31;
isch_map[0x1442f705efULL] = 32;
isch_map[0x1476ca8078ULL] = 33;
isch_map[0x141a3cafa1ULL] = 34;
isch_map[0x142e012a36ULL] = 35;
isch_map[0x14df54a49eULL] = 36;
isch_map[0x14eb692109ULL] = 37;
isch_map[0x14879f0ed0ULL] = 38;
isch_map[0x14b3a28b47ULL] = 39;
isch_map[0x1d467a9e9dULL] = 40;
isch_map[0x1d72471b0aULL] = 41;
isch_map[0x1d1eb134d3ULL] = 42;
isch_map[0x1d2a8cb144ULL] = 43;
isch_map[0x1ddbd93fecULL] = 44;
isch_map[0x1defe4ba7bULL] = 45;
isch_map[0x1d831295a2ULL] = 46;
isch_map[0x1db72f1035ULL] = 47;
isch_map[0x164af0f210ULL] = 48;
isch_map[0x167ecd7787ULL] = 49;
isch_map[0x16123b585eULL] = 50;
isch_map[0x162606ddc9ULL] = 51;
isch_map[0x16d7535361ULL] = 52;
isch_map[0x16e36ed6f6ULL] = 53;
isch_map[0x168f98f92fULL] = 54;
isch_map[0x16bba57cb8ULL] = 55;
isch_map[0x1f4e7d6962ULL] = 56;
isch_map[0x1f7a40ecf5ULL] = 57;
isch_map[0x1f16b6c32cULL] = 58;
isch_map[0x1f228b46bbULL] = 59;
isch_map[0x1fd3dec813ULL] = 60;
isch_map[0x1fe7e34d84ULL] = 61;
isch_map[0x1f8b15625dULL] = 62;
isch_map[0x1fbf28e7caULL] = 63;
isch_map[0x084d62c339ULL] = 64;
isch_map[0x08795f46aeULL] = 65;
isch_map[0x0815a96977ULL] = 66;
isch_map[0x082194ece0ULL] = 67;
isch_map[0x08d0c16248ULL] = 68;
isch_map[0x08e4fce7dfULL] = 69;
isch_map[0x08880ac806ULL] = 70;
isch_map[0x08bc374d91ULL] = 71;
isch_map[0x0149ef584bULL] = 72;
isch_map[0x017dd2dddcULL] = 73;
isch_map[0x011124f205ULL] = 74;
isch_map[0x0125197792ULL] = 75;
isch_map[0x01d44cf93aULL] = 76;
isch_map[0x01e0717cadULL] = 77;
isch_map[0x018c875374ULL] = 78;
isch_map[0x01b8bad6e3ULL] = 79;
isch_map[0x0a456534c6ULL] = 80;
isch_map[0x0a7158b151ULL] = 81;
isch_map[0x0a1dae9e88ULL] = 82;
isch_map[0x0a29931b1fULL] = 83;
isch_map[0x0ad8c695b7ULL] = 84;
isch_map[0x0aecfb1020ULL] = 85;
isch_map[0x0a800d3ff9ULL] = 86;
isch_map[0x0ab430ba6eULL] = 87;
isch_map[0x0341e8afb4ULL] = 88;
isch_map[0x0375d52a23ULL] = 89;
isch_map[0x03192305faULL] = 90;
isch_map[0x032d1e806dULL] = 91;
isch_map[0x03dc4b0ec5ULL] = 92;
isch_map[0x03e8768b52ULL] = 93;
isch_map[0x038480a48bULL] = 94;
isch_map[0x03b0bd211cULL] = 95;
isch_map[0x044dbc12b7ULL] = 96;
isch_map[0x0479819720ULL] = 97;
isch_map[0x041577b8f9ULL] = 98;
isch_map[0x04214a3d6eULL] = 99;
isch_map[0x04d01fb3c6ULL] = 100;
isch_map[0x04e4223651ULL] = 101;
isch_map[0x0488d41988ULL] = 102;
isch_map[0x04bce99c1fULL] = 103;
isch_map[0x0d493189c5ULL] = 104;
isch_map[0x0d7d0c0c52ULL] = 105;
isch_map[0x0d11fa238bULL] = 106;
isch_map[0x0d25c7a61cULL] = 107;
isch_map[0x0dd49228b4ULL] = 108;
isch_map[0x0de0afad23ULL] = 109;
isch_map[0x0d8c5982faULL] = 110;
isch_map[0x0db864076dULL] = 111;
isch_map[0x0645bbe548ULL] = 112;
isch_map[0x06718660dfULL] = 113;
isch_map[0x061d704f06ULL] = 114;
isch_map[0x06294dca91ULL] = 115;
isch_map[0x06d8184439ULL] = 116;
isch_map[0x06ec25c1aeULL] = 117;
isch_map[0x0680d3ee77ULL] = 118;
isch_map[0x06b4ee6be0ULL] = 119;
isch_map[0x0f41367e3aULL] = 120;
isch_map[0x0f750bfbadULL] = 121;
isch_map[0x0f19fdd474ULL] = 122;
isch_map[0x0f2dc051e3ULL] = 123;
isch_map[0x0fdc95df4bULL] = 124;
isch_map[0x0fe8a85adcULL] = 125;
isch_map[0x0f845e7505ULL] = 126;
isch_map[0x0fb063f092ULL] = 127;
isch_map[0x575d57f7ffULL] = -2; // S-ISCH
}
//I-ISCH Lookup, borrowed from OP25 (now w/ error correction)
int isch_lookup (uint64_t isch)
{
map_isch(); //initialize the lookup map
int decoded = -2;
// Must contain bit errors if no exact match, so
// look for codeword with smallest hamming distance
if (isch_map.find(isch) == isch_map.end())
{
int popct, popmin = 40;
for (auto it = isch_map.begin(); it != isch_map.end(); ++it)
{
popct = __builtin_popcountll(isch ^ it->first);
// Encoding is (40, 9, 16) which can correct at most 7 bit-errors
if ((popct <= 7) && (popct < popmin))
{
decoded = it->second;
popmin = popct;
}
}
return decoded;
}
else // No errors, so simply return the matching value
decoded = isch_map[isch];
return decoded;
}