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package static ushort calcHeaderCrc(bool aStartupFrame, bool aSyncFrame, ushort aFrameId, ushort aPayloadWords) {
uint crcData = aPayloadWords;
crcData |= (aFrameId << 7);
if (aSyncFrame) {
crcData |= BIT_19;
}
if (aStartupFrame) {
crcData |= BIT_18;
}
ushort crc = 0x1a;
const ushort table[16] = [
0x0000, 0x0385, 0x070A, 0x048F,
0x0591, 0x0614, 0x029B, 0x011E,
0x00A7, 0x0322, 0x07AD, 0x0428,
0x0536, 0x06B3, 0x023C, 0x01B9
];
for (int i = 0; i < 5; ++i) {
if (i != 0) {
crcData <<= 4;
}
crc = ((crc << 4) & 0x7FF) ^ table[((crc >> 7) ^ (crcData >> 16)) & 0x0F];
}
return(crc);
}
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