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    SubjectRe: [PATCH 6/9] drivers/net/wireless/iwlwifi/iwl-4965.c: Correct use of ! and &
    All,

    >>> i think there might be similar patterns: "x & !y", "!x | y", "x | !y" ?
    >>>
    >> Well, (!x & y) and (!x | y) are probably the two that might have been
    >> intended otherwise. (x & !y), (x | !y) are probably ok.
    >
    > i think the proper intention in the latter cases is (x & ~y) and
    > (x | ~y).
    >
    > My strong bet is that in 99% of the cases they are real bugs and && or
    > || was intended.

    Developer knowledge of operator precedence and the issue of what
    they intended to write are interesting topics. Some experimental
    work is described in (binary operators only I'm afraid):

    www.knosof.co.uk/cbook/accu06a.pdf
    www.knosof.co.uk/cbook/accu07a.pdf

    The ACCU 2006 experiment provides evidence that developer knowledge
    is proportional to the number of occurrences of a construct in
    source code, it also shows a stunningly high percentage of incorrect
    answers.

    The ACCU 2007 experiment provides evidence that the names of the
    operands has a significant impact on operator precedence choice.

    I wonder what kind of names are used as the operand of unary
    operators?

    I would expect the ~ operator to have a bitwise name, but the
    ! operator might have an arithmetic or bitwise name.

    --
    Derek M. Jones tel: +44 (0) 1252 520 667
    Knowledge Software Ltd mailto:derek@knosof.co.uk
    Applications Standards Conformance Testing http://www.knosof.co.uk


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