Memory Alignment

Collaboration diagram for Memory Alignment:

Detailed Description

Memory alignment support macros
#define	MEM_ALIGN_MASK(a)   ((size_t)(a) - 1U)
	Alignment mask constant. More...
#define	MEM_ALIGN_PREV(p, a)
	Aligns to the previous aligned memory address. More...
#define	MEM_ALIGN_NEXT(p, a)
	Aligns to the next aligned memory address. More...
#define	MEM_IS_ALIGNED(p, a)   (((size_t)(p) & MEM_ALIGN_MASK(a)) == 0U)
	Returns whatever a pointer or memory size is aligned. More...
#define	MEM_IS_VALID_ALIGNMENT(a)   (((size_t)(a) != 0U) && (((size_t)(a) & ((size_t)(a) - 1U)) == 0U))
	Returns whatever a constant is a valid alignment. More...

Macro Definition Documentation

#define MEM_ALIGN_MASK

(

a

)

((size_t)(a) - 1U)

Alignment mask constant.

Parameters

[in]

a

alignment, must be a power of two

Definition at line 59 of file chalign.h.

Referenced by chPoolFreeI().

#define MEM_ALIGN_PREV	(		p,
			a
	)

Value:

/*lint -save -e9033 [10.8] The cast is safe.*/                            \
  ((size_t)(p) & ~MEM_ALIGN_MASK(a))                                        \
  /*lint -restore*/

Aligns to the previous aligned memory address.

Parameters

[in]	p	variable to be aligned
[in]	a	alignment, must be a power of two

Definition at line 67 of file chalign.h.

#define MEM_ALIGN_NEXT	(		p,
			a
	)

Value:

/*lint -save -e9033 [10.8] The cast is safe.*/                            \
  MEM_ALIGN_PREV((size_t)(p) + MEM_ALIGN_MASK(a), (a))                      \
  /*lint -restore*/

Aligns to the next aligned memory address.

Parameters

[in]	p	variable to be aligned
[in]	a	alignment, must be a power of two

Definition at line 78 of file chalign.h.

Referenced by chCoreAllocAlignedWithOffsetI(), chHeapAllocAligned(), chHeapFree(), chHeapObjectInit(), chThdCreateStatic(), and chThdCreateSuspendedI().

#define MEM_IS_ALIGNED	(		p,
			a
	)		(((size_t)(p) & MEM_ALIGN_MASK(a)) == 0U)

Returns whatever a pointer or memory size is aligned.

Parameters

[in]	p	variable to be aligned
[in]	a	alignment, must be a power of two

Definition at line 89 of file chalign.h.

Referenced by chHeapFree(), chThdCreateStatic(), and chThdCreateSuspendedI().

#define MEM_IS_VALID_ALIGNMENT

(

a

)

(((size_t)(a) != 0U) && (((size_t)(a) & ((size_t)(a) - 1U)) == 0U))

Returns whatever a constant is a valid alignment.

Valid alignments are powers of two.

Parameters

[in]

a

alignment to be checked, must be a constant

Definition at line 97 of file chalign.h.

Referenced by chCoreAllocAlignedWithOffsetI(), and chHeapAllocAligned().