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    Subject[PATCH 1/2] bitreversal program
    --- a/include/linux/bitrev.h    2008-04-17 08:19:44.000000000 +0530
    +++ b/include/linux/bitrev.h 2008-05-19 21:49:46.000000000 +0530
    @@ -3,11 +3,32 @@

    #include <linux/types.h>

    -extern u8 const byte_rev_table[256];
    +/**
    + * Here is a generalised bit reversal program
    + * @x: word to get bits reversed
    + * @k: key, explained below
    + * for k = 31, it reverses the bits of word(32 bit)
    + * for k = 24, it reverses the bytes in word
    + * for k = 7, it reverses the bits in every byte without
    + * changing the positions of bytes in a word
    + * and for k = 16 it swaps the left and right halves of a
    + * word
    + */

    -static inline u8 bitrev8(u8 byte)
    +static inline u32 gen_bit_rev(u32 x, u32 k)
    {
    - return byte_rev_table[byte];
    + if(k & 1)
    + x = (x & 0x55555555) << 1 | (x & 0xaaaaaaaa) >> 1;
    + if(k & 2)
    + x = (x & 0x33333333) << 2 | (x & 0xcccccccc) >> 2;
    + if(k & 4)
    + x = (x & 0x0f0f0f0f) << 4 | (x & 0xf0f0f0f0) >> 4;
    + if(k & 8)
    + x = (x & 0x00ff00ff) << 8 | (x & 0xff00ff00) >> 8;
    + if(k & 16)
    + x = (x & 0x0000ffff) << 16 | (x & 0xffff0000) >> 16;
    +
    + return x;
    }

    extern u32 bitrev32(u32 in);
    --
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