字节对齐

1
2
3
4
5
6
7
8
9
10
11
/**
 * @def RT_ALIGN(size, align)
 * Return the most contiguous size aligned at specified width. RT_ALIGN(13, 4) would return 16.
 */
#define RT_ALIGN(size, align)           (((size) + (align) - 1) & ~((align) - 1))

/**
 * @def RT_ALIGN_DOWN(size, align)
 * Return the down number of aligned at specified width. RT_ALIGN_DOWN(13, 4) would return 12.
 */
#define RT_ALIGN_DOWN(size, align)      ((size) & ~((align) - 1))