FreeCalypso > hg > gsm-codec-lib

annotate dev/efr-sid-insert.c @ 202:0faf23a9286f

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libgsmefr/reorder.c: perf opt
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 04 Jan 2023 04:54:02 +0000
parents 3b5958f28a40
children
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3b5958f28a40 dev: efr-sid-insert helper program
Mychaela Falconia <falcon@freecalypso.org>
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1 /*
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2 * We need to implement a function that inserts the 95 bit wide SID
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Mychaela Falconia <falcon@freecalypso.org>
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3 * codeword into the frame, and we would like to do it more efficiently
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4 * than calling a "set bit" function for each of the 95 bits. This
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5 * program will produce a more efficient solution.
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6 */
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7
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8 #include <stdio.h>
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9 #include <stdint.h>
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10 #include <stdlib.h>
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11 #include <string.h>
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12
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13 static const uint8_t SID_codeword_bit_idx[95] =
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14 {
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15 45, 46, 48, 49, 50, 51, 52, 53, 54, 55,
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16 56, 57, 58, 59, 60, 61, 62, 63, 64, 65,
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17 66, 67, 68, 94, 95, 96, 98, 99, 100, 101,
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18 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
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19 112, 113, 114, 115, 116, 117, 118, 148, 149, 150,
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20 151, 152, 153, 154, 155, 156, 157, 158, 159, 160,
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21 161, 162, 163, 164, 165, 166, 167, 168, 169, 170,
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22 171, 196, 197, 198, 199, 200, 201, 202, 203, 204,
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23 205, 206, 207, 208, 209, 212, 213, 214, 215, 216,
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24 217, 218, 219, 220, 221
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25 };
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27 static void set_bit(uint8_t *frame, unsigned bitnum)
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28 {
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29 unsigned bytenum = bitnum >> 3;
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30 unsigned bit_in_byte = 7 - (bitnum & 7);
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31 unsigned bitmask = 1 << bit_in_byte;
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32
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33 frame[bytenum] |= bitmask;
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34 }
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35
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36 main(argc, argv)
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37 char **argv;
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38 {
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39 uint8_t bytes[31];
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40 unsigned n;
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41
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42 memset(bytes, 0, 31);
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43 for (n = 0; n < 95; n++)
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44 set_bit(bytes, SID_codeword_bit_idx[n] + 4);
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45 for (n = 0; n < 31; n++)
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46 if (bytes[n])
3b5958f28a40 dev: efr-sid-insert helper program
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47 printf("\tframe[%u] |= 0x%02X;\n", n, bytes[n]);
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48 exit(0);
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49 }