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lib/math32.h: add IS_POWER_OF_2 macro

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This adds IS_POWER_OF_2 macro to help catching config errors at
build time.

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>
This commit is contained in:
Yanfeng Liu 2024-05-30 15:10:06 +08:00 committed by Xiang Xiao
parent 6f49637e23
commit caff9eba28
1 changed files with 5 additions and 1 deletions
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6
include/nuttx/lib/math32.h
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@ -52,11 +52,15 @@
#define FLS2(n) ((n) & 0x2 ? 1 + FLS1 ((n) >> 1) : FLS1 (n))
#define FLS1(n) ((n) & 0x1 ? 1 : 0)
/* Checks if an integer is power of two at compile time */
#define IS_POWER_OF_2(n) ((n) > 0 && ((n) & (n - 1)) == 0)
/* Returns round up and round down value of log2(n). Note: it can be used at
* compile time.
*/
#define LOG2_CEIL(n) ((n) & (n - 1) ? FLS(n) : FLS(n) - 1)
#define LOG2_CEIL(n) (IS_POWER_OF_2(n) ? FLS(n) - 1 : FLS(n))
#define LOG2_FLOOR(n) (FLS(n) - 1)
/****************************************************************************