JBUS protocol (continued)
Example of CRC 16 computation in "C" using table lookup
#define CPH 0 /* most significant bytes */ #define CPL 1 /* least significant bytes */
/* TABLE OF MOST SIGNIFICANT BYTES FOR CRC16 COMPUTATION */
char tbcrch [ ] =
{
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
1,192,128,65,0,193,129,64,0,193,129,64,1,192,128,65,
0,193,129,64,1,192,128,65,1,192,128,65,0,193,129,64,
};
/* TABLE OF LEAST SIGNIFICANT BYTES FOR CRC16 COMPUTATION */
char tbcrcl [ ] =
{
0,192,193,1,195,3,2,194,198,6,7,199,5,197,196,4,
204,12,13,205,15,207,206,14,10,202,203,11,201,9,8,200,
216,24,25,217,27,219,218,26,30,222,223,31,221,29,28,220,
20,212,213,21,215,23,22,214,210,18,19,211,17,209,208,16,
240,48,49,241,51,243,242,50,54,246,247,55,245,53,52,244,
60,252,253,61,255,63,62,254,250,58,59,251,57,249,248,56,
40,232,233,41,235,43,42,234,238,46,47,239,45,237,236,44,
228,36,37,229,39,231,230,38,34,226,227,35,225,33,32,224,
160,96,97,161,99,163,162,98,102,166,167,103,165,101,100,164,
108,172,173,109,175,111,110,174,170,106,107,171,105,169,168,104,
120,184,185,121,187,123,122,186,190,126,127,191,125,189,188,124,
180,116,117,181,119,183,182,118,114,178,179,115,177,113,112,176,
80,144,145,81,147,83,82,146,150,86,87,151,85,149,148,84,
156,92,93,157,95,159,158,94,90,154,155,91,153,89,88,152,
136,72,73,137,75,139,138,74,78,142,143,79,141,77,76,140,
68,132,133,69,135,71,70,134,130,66,67,131,65,129,128,64,
};
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