vcsa and big endian - Kernel

This is a discussion on vcsa and big endian - Kernel ; Hello, On big endian machines, /dev/vcsa stores text/attribute bytes in big endian order, while it stores them in little endian order on little endian machines. Is that expected? Samuel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" ...

+ Reply to Thread
Results 1 to 4 of 4

Thread: vcsa and big endian

  1. vcsa and big endian

    Hello,

    On big endian machines, /dev/vcsa stores text/attribute bytes in big
    endian order, while it stores them in little endian order on little
    endian machines. Is that expected?

    Samuel
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  2. Re: vcsa and big endian

    Samuel Thibault, le Sun 09 Dec 2007 23:43:49 +0100, a écrit :
    > On big endian machines, /dev/vcsa stores text/attribute bytes in big
    > endian order, while it stores them in little endian order on little
    > endian machines. Is that expected?


    It looks like ggi considers this as normal. In any case, the vcsa
    manual page should probably be made more clear ("but including
    attributes" -> "but using unsigned shorts that include attributes" for
    instance).

    Samuel
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  3. Re: vcsa and big endian

    Samuel Thibault, le Sun 09 Dec 2007 23:50:39 +0100, a écrit :
    > Samuel Thibault, le Sun 09 Dec 2007 23:43:49 +0100, a écrit :
    > > On big endian machines, /dev/vcsa stores text/attribute bytes in big
    > > endian order, while it stores them in little endian order on little
    > > endian machines. Is that expected?

    >
    > It looks like ggi considers this as normal. In any case, the vcsa
    > manual page should probably be made more clear ("but including
    > attributes" -> "but using unsigned shorts that include attributes" for
    > instance).


    And the code example should be fixed too:

    char ch, attrib;

    (void) read(fd, &ch, 1);
    (void) read(fd, &attrib, 1);

    should rather be

    unsigned short s;
    unsigned char ch, attrib;

    ...

    (void) read(fd, &s, 2);
    ch = s & 0xff;
    attrib = (s >> 8);


    The manual page should also mention that when a 512 chars font is
    loaded, the 9th bit is in the attrib value, and its position can be
    fetched through the VT_GETHIFONTMASK ioctl.

    Samuel
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  4. Re: vcsa and big endian

    On Sun 2007-12-09 23:50:39, Samuel Thibault wrote:
    > Samuel Thibault, le Sun 09 Dec 2007 23:43:49 +0100, a écrit :
    > > On big endian machines, /dev/vcsa stores text/attribute bytes in big
    > > endian order, while it stores them in little endian order on little
    > > endian machines. Is that expected?

    >
    > It looks like ggi considers this as normal. In any case, the vcsa
    > manual page should probably be made more clear ("but including
    > attributes" -> "but using unsigned shorts that include attributes" for
    > instance).


    I'd say you need stronger warning than that, "warning, vcsa is in host
    byte endianity" or something.

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pav...rses/blog.html
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

+ Reply to Thread