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C51 - Calculating the parity

Chris s over 18 years ago

Has someone a good hint how to implement a parity-calculation of a byte in the most efficient way on an C51-device?

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0 Michael Hoffman over 18 years ago

Here's a simple one:

static char const code nibble_parity[16] =
                   { 0, 1, 1, 0,
                     1, 0, 0, 1,
                     1, 0, 0, 1,
                     0, 1, 1, 0 };
char calc_even_parity(uchar byte)
{
    return( nibble_parity[byte&0xf] ^ nibble_parity[(byte>>4)&0xf]);
}

char calc_odd_parity(uchar byte)
{
    return(!calc_even_parity(byte));
}

I've been using it for years

Reply

0 Michael Hoffman over 18 years ago

Here's a simple one:

static char const code nibble_parity[16] =
                   { 0, 1, 1, 0,
                     1, 0, 0, 1,
                     1, 0, 0, 1,
                     0, 1, 1, 0 };
char calc_even_parity(uchar byte)
{
    return( nibble_parity[byte&0xf] ^ nibble_parity[(byte>>4)&0xf]);
}

char calc_odd_parity(uchar byte)
{
    return(!calc_even_parity(byte));
}

I've been using it for years

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