le32_to_cpu and cpu_to_le32

最新推荐文章于 2025-01-13 19:03:17 发布

原创最新推荐文章于 2025-01-13 19:03:17 发布 · 2.3k 阅读

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#macros

本文介绍了le32_to_cpu和cpu_to_le32宏的作用及使用场景。前者用于将32位小端序数据转换为CPU本机字节序，后者则进行相反的操作。通过这些宏可以清晰地表明代码中数据的字节序状态，提高代码可读性。

Then when do we use le32_to_cpu( ) , and when do we use cpu_to_le32( )?
>
> The names tell it. le32_to_cpu is used for convesions from 32bit little
> endian data into CPUs endianness, cpu_to_le32 is used for convesions from
> CPU endianness to little endian 32bit data.
> Actually, both macros do the same thing, but one should make the differences
> clear to make code more readable so that anyone can quickly find out whether
> some data is kept in native endianness or some particular one.
>

code example of big endian and little endian

// 2-byte number

int SHORT_little_endian_TO_big_endian(int i)

{

    return ((i>>8)&0xff)+((i << 8)&0xff00);

}



// 4-byte number

int INT_little_endian_TO_big_endian(int i)

{

    return((i&0xff)<<24)+((i&0xff00)<<8)+((i&0xff0000)>>8)+((i>>24)&0xff);

}