Defines

Defines. More...

Collaboration diagram for Defines:

Detailed Description

Defines.

Macros
#define	ALIGNED(alignment)   __attribute__((aligned(alignment)))
	GCC aligned attribute.
#define	PACKED   __attribute__((packed))
	GCC packed attribute.
#define	NORETURN   __attribute__((noreturn))
	GCC noreturn function attribute.
#define	NOINLINE   __attribute__((noinline))
	GCC noinline function attribute.
#define	CONST_FUNC   __attribute__((const))
	GCC const function attribute.
#define	PURE   __attribute__((pure))
	GCC.
#define	CONCAT(a, b)   CONCAT_INNER(a, b)
	Concatenates two tokens.
#define	CONCAT_INNER(a, b)   a##b
	Inner helper macro for token concatenation.
#define	RED_ZONE_SIZE   128
	The size of the red zone in bytes.
#define	UNUSED(x)   (void)(x)
	Mark a variable as unused.
#define	ARRAY_SIZE(x)   ((size_t)(sizeof(x) / sizeof((x)[0])))
	Get the number of elements in a static array.
#define	LIKELY(x)   __builtin_expect(!!(x), 1)
	Mark a condition as likely.
#define	UNLIKELY(x)   __builtin_expect(!!(x), 0)
	Mark a condition as unlikely.

Macro Definition Documentation

ALIGNED

#define ALIGNED

(

alignment

)

__attribute__((aligned(alignment)))

GCC aligned attribute.

Tells the compiler to align a variable or structure field to the specified byte alignment.

Usefull for caching or hardware requirements.

Definition at line 23 of file defs.h.

PACKED

#define PACKED   __attribute__((packed))

GCC packed attribute.

Tells the compiler to pack a structure, meaning there will be no padding between members.

Needed for most hardware structures.

Definition at line 33 of file defs.h.

NORETURN

#define NORETURN   __attribute__((noreturn))

GCC noreturn function attribute.

Tells the compiler that the fuction with said attribute will never return.

Definition at line 40 of file defs.h.

NOINLINE

#define NOINLINE   __attribute__((noinline))

GCC noinline function attribute.

Tells the compiler to never inline the function with said attribute.

Definition at line 48 of file defs.h.

CONST_FUNC

#define CONST_FUNC   __attribute__((const))

GCC const function attribute.

Tells the compiler that the fuction with said attribute only depends on the arguments passed to it, and will never access global variables.

Definition at line 57 of file defs.h.

PURE

#define PURE   __attribute__((pure))

GCC.

The PURE attribute tells gcc that the function with said attribute only depends on the arguments passed to it and potentially global variables.

Definition at line 66 of file defs.h.

CONCAT

#define CONCAT	(		a,
			b
	)		CONCAT_INNER(a, b)

Concatenates two tokens.

This macro concatenates two tokens a and b into a single token.

Parameters

a	The first token.
b	The second token.

Returns

The concatenated token.

Definition at line 77 of file defs.h.

CONCAT_INNER

#define CONCAT_INNER	(		a,
			b
	)		a##b

Inner helper macro for token concatenation.

Definition at line 82 of file defs.h.

RED_ZONE_SIZE

#define RED_ZONE_SIZE   128

The size of the red zone in bytes.

The red zone is a region of memory below the stack pointer that is reserved and should not be modified by interrupt handlers or signal handlers. The compiler uses this area for temporary storage for the purpose of optimization.

Definition at line 91 of file defs.h.

UNUSED

#define UNUSED

(

x

)

(void)(x)

Mark a variable as unused.

This macro marks a variable as unused to prevent compiler warnings about unused variables.

Parameters

x	The variable to mark as unused.

Definition at line 100 of file defs.h.

ARRAY_SIZE

#define ARRAY_SIZE

(

x

)

((size_t)(sizeof(x) / sizeof((x)[0])))

Get the number of elements in a static array.

Parameters

x	The array.

Returns

The number of elements in the array.

Definition at line 108 of file defs.h.

LIKELY

#define LIKELY

(

x

)

__builtin_expect(!!(x), 1)

Mark a condition as likely.

This macro marks a condition as likely to help the compiler optimize branch prediction.

Parameters

x	The condition.

Definition at line 117 of file defs.h.

UNLIKELY

#define UNLIKELY

(

x

)

__builtin_expect(!!(x), 0)

Mark a condition as unlikely.

This macro marks a condition as unlikely to help the compiler optimize branch prediction.

Parameters

x	The condition.

Definition at line 126 of file defs.h.