lkml.org 
[lkml]   [1999]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: le32_to_cpu() help...
    Date
    On Tue, 02 Nov 1999, Jes Sorensen wrote:
    > >>>>> "Dony" == dony <dony.he@huawei.com.cn> writes:
    >
    > Dony> On Tue, 02 Nov 1999, Jes Sorensen wrote:
    > >> They translate data to little endian from big endian on big endian
    > >> CPUs, on little endian CPUs like the x86 they are noops. We need
    > >> these because some hardware and other things like file systems
    > >> wants data in little endian order no matter what type of system you
    > >> are running on.
    >
    > Dony> Then when do we use le32_to_cpu( ) , and when do we use
    > Dony> cpu_to_le32( )?
    >
    > You use le32_to_cpu() when you want to read data which is in little
    > endian order and you use the other one when you try to write it.
    >
    I know this. I just don't know what data is in little endian and what data is
    in big endian. say the following code ....

    struct ext2_super_block * es;
    struct super_block * sb;
    ..............................
    es->smtime=cpu_to_le32(CURRENT_TIME); //why here use cpu_to_le32?
    sb->u.ext2_sb.s_mount_state=le32_to_cpu(es->state); //why use le32_to_cpu here?



    --
    ####################################
    Linux is more powerful than windows
    dony.he@huawei.com.cn
    ####################################

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

    \
     
     \ /
      Last update: 2005-03-22 13:54    [W:0.020 / U:31.064 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site