bit manipulation

This is a discussion on bit manipulation within the C Programming forums, part of the General Programming Boards category; Hi, I would like to do the following: (i) from a 24bit hexadecimal mask, I would like to know which ...

  1. #1
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    bit manipulation

    Hi,

    I would like to do the following:

    (i) from a 24bit hexadecimal mask, I would like to know which bit in ON (1).

    (ii) from a 16 bit data word I would like to read the 12 bits (starting from LSB) and 13-16 bits separately


    How do I do this?

  2. #2
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    What DO YOU think?

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    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  3. #3
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    Wink

    for masking bits... why don't use exclusive disjunction? (if c does not implement it it could be easily implemented with logic or "|" and logic and "&" operators)

    your could compare your result with something like pow(2,n) to know if right n-most bit is on or not.

    Regards
    Mac OS 10.6 Snow Leopard : Darwin

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    anybody has a piece of code?

  5. #5
    Algorithm Dissector iMalc's Avatar
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    If you're a beginner then you'll learn more by working out the answer yourself, or at the very least looking it up yourself online.
    If not, then you'll already know how to do it.

    We don't help people cheat if that's what you're after.
    My homepage
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    Thanks!!

    But I thought having a piece of simple code to look at is a process of learning and posting a question in a forum is the way to learn from internet.

    But anyway, thanks again for redefining "learning" and "cheating".

    Be happy always!

  7. #7
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    Right, there was two purposes to my original "what do you think":
    1. How much do you actually know about the subject.
    2. You need to learn by doing, not by copying.

    I may very well be able to post a piece of example code, but without knowing the level of your understanding, the example code may not be meaningful to you.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  8. #8
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    Quote Originally Posted by matsp View Post
    I may very well be able to post a piece of example code, but without knowing the level of your understanding, the example code may not be meaningful to you.
    Let's have a test:

    Code:
    ((1 << b) - 1) << c
    Greets,
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  9. #9
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by dsupriya View Post
    Thanks!!

    But I thought having a piece of simple code to look at is a process of learning and posting a question in a forum is the way to learn from internet.

    But anyway, thanks again for redefining "learning" and "cheating".

    Be happy always!
    Posting a question in a forum is indeed a way to learn from the internet.

    Note the complete absence of "having someone write your code for you".

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