diff options
Diffstat (limited to 'include/rtdef.h')
| -rw-r--r-- | include/rtdef.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/rtdef.h b/include/rtdef.h index 01667001b5..f2f1266de0 100644 --- a/include/rtdef.h +++ b/include/rtdef.h @@ -137,9 +137,14 @@ typedef rt_uint32_t rt_off_t; /* Type for offset. */ /** * @def RT_ALIGN(size, align) * Return the most contiguous size aligned at specified width. RT_ALIGN(13, 4) - * would equal to 16. It is needed in some critical contexts. + * would return 16. + * + * @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(size, align) (((size) + (align) - 1) & ~((align)-1)) +#define RT_ALIGN_DOWN(size, align) ((size) & ~((align) -1)) /** * @def RT_NULL |