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    • if not executed, but true

    Posted by ulix on 2018-01-13 12:29

    Hi,

    I want to execute this line in my code:

    if (value_1 > 32767) value_1 -= 65536;

    value_1 gets for excample an value of: 65540 (uint_16t) and
    int16_t value_1 = 0; is like this decleared before getting the value.

    why isnt it executed? Its true!
    Thank you

    Reads: 8450
    Posted by dautrevaux on 2018-01-13 15:14 France

    Hi,

    if you declare value_1 as uint16_t value_1; as your message implies, your code works as expected: the possible values for value_1 goes from -32768 to 32767, so can never be greater than 32767!...

    In fact your code is useless: 16-bit twos-complement arithmetic implies that the values for value_1 wraps from 32767 to -32768 automatically as you are working in modulo 65536 arithmetic. Note that this also means that value_1 -= 32768; is in fact a No-Operation!

    Hope this helps,

    Bernard (Ac6)


     
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