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common.h: Make IS_ALIGNED() safe for testing with alignment == 0 #10322

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jsarha wants to merge 1 commit into from
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common.h: Make IS_ALIGNED() safe for testing with alignment == 0 #10322

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2 changes: 1 addition & 1 deletion src/include/sof/common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@

/* Align the number to the nearest alignment value */
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Copilot AI Oct 22, 2025

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The macro lacks documentation explaining the behavior when alignment is 0. Add a comment clarifying that zero alignment is treated as always aligned (returns true), which prevents division by zero in the modulo operation.

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/* Align the number to the nearest alignment value */
/* Align the number to the nearest alignment value */
/* If alignment is zero, IS_ALIGNED returns true (treats all values as aligned).
* This prevents division by zero in the modulo operation.
*/

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#ifndef IS_ALIGNED
#define IS_ALIGNED(size, alignment) ((size) % (alignment) == 0)
#define IS_ALIGNED(size, alignment) (!(alignment) || (size) % (alignment) == 0)
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@abonislawski abonislawski Oct 23, 2025

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I think we are using Zephyr version (included above) and this version of IS_ALIGNED wont be used (#ifndef IS_ALIGNED)

#ifdef __ZEPHYR__
#include <zephyr/sys/util.h>
#endif

btw alignment 0 is incorrect anyway so maybe this macro was called somewhere where it shouldnt?

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@jsarha jsarha Oct 23, 2025

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Whether it is incorrect or not, is a matter of definition. But apparently this change is useless on its own, so I'll close it.

#endif

/* Treat zero as a special case because it wraps around */
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