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    SubjectRe: [PATCH 2/3] Import fw-ohci driver.
    Kristian Høgsberg wrote:
    > Stefan Richter wrote:
    >> Kristian Høgsberg wrote:
    >>> Yup, I've done away with the bitfields and switched to a mix of __le16
    >>> and __le32 struct fields.
    >> I suppose the struct should get __attribute__((packed)) then.
    > I guess it wouldn't harm, but is it really necessary? Would gcc ever
    > insert padding here, all the 32 bit fields a 32 bit aligned, and so are
    > the 16 bit fields.

    Is 2-byte alignment of 16bit struct members guaranteed on all platforms?

    A related question:
    If I specify a struct which, among else, contains 32bit quantities, then
    any variable of this struct type is supposed to be at least 4-byte-aligned.
    No if I specifiy this struct as packed, will variables of this type still
    be aligned on 4 byte boundaries or will the compiler assume no alignment?
    In other words, should it be __attribute__((packed,aligned(4))) then?
    I'm speaking about situations where I not only wish to avoid unnecessarily
    bad machine code due to unaligned access but where the device requires
    4-byte alignment too.
    Stefan Richter
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      Last update: 2006-12-11 00:01    [W:0.023 / U:12.316 seconds]
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