31 lines
796 B
C
31 lines
796 B
C
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void ldpc32_table_(int cw[])
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{
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// Compute and return the table of 65535 codewords for the (32,16) code.
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// Array y contains the sixteen rows (columns) of the parity-check matrix
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int y[16] = { 0xd452, 0x7ecb, 0xc5d5, 0xf81c,
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0x61d7, 0x0ed8, 0xa3c5, 0x9ef9,
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0xb3bd, 0xe5b6, 0x2fcd, 0xc23a,
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0x5deb, 0xfa0e, 0x35fc, 0x1379 };
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unsigned int c[2]; /* Codeword composed of 16-bit info and 16-bit parity */
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int i,j,k;
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int aux;
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int weight(int vector);
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for(k=0; k<65536; k++) {
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c[0] = k;
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c[1] = 0;
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for (i=0; i<16; i++) {
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aux = 0;
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for (j=0; j<16; j++) {
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aux = aux ^ ((c[0] & y[i]) >> j & 1);
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}
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c[1] = (c[1] << 1) ^ aux;
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}
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cw[k]=65536*c[1] + c[0];
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}
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}
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