Basic type definitions and useful macros. More...

#include <stdint.h>

Macros
#define	_EXTERN_C_DECL_BEGIN
	Open C++ header file declarations.

#define	_EXTERN_C_DECL_END
	Close C++ header file declarations.

#define	UNUSED(X) ((void)(X))
	Tell the compiler that the variable X is left unsed. More...

#define	STATIC_ASSERT(C, M) extern char _static_assertion_##M[(C) ? 1 : -1]
	Perform an assertion at compile time. More...

#define	NULL ((void *)0)
	NULL pointer.

#define	true ((bool)1)
	Boolean TRUE constant value.

#define	false ((bool)0)
	Boolean FALSE constant value.

#define	ALLOW_ARITHM(X) ((uint8_t *)(X))
	Allow arithmetic on a void pointer. More...

#define	STATIC_CHECK_TYPE(V, T) UNUSED(1 ? (T*)0 : &(V))
	Check that the lvalue V is of type T at compile time. More...

#define	SET_BITS(V, T, X)
	Set the corresponding bits of X in the value V of type T. More...

#define	CLEAR_BITS(V, T, X)
	Clear the corresponding bits of X in the value V of type T. More...

#define	POSITION(X) (1U << (X))
	Define a constant bit at position X, starting from index 0. More...

#define	INDIRECT_T(X, T) ((volatile T *)(X))
	Define an indirect read/write variable at an absolute address. More...

#define	INDIRECT(X) INDIRECT_T(X, uint8_t)
	Define an indirect read/write register at an absolute address. More...

#define	DIRECT_T(X, T) (*INDIRECT_T(X, T))
	Define a direct read/write variable at an absolute address. More...

#define	DIRECT(X) DIRECT_T(X, uint8_t)
	Define a direct read/write register at an absolute address. More...

#define	LO8(X) ((uint8_t)(X))
	Take the low byte of a 16-bit value. More...

#define	HI8(X) LO8((X) >> 8U)
	Take the high byte of a 16-bit value. More...

#define	MIN(A, B) (((A) < (B)) ? (A) : (B))
	Obtain the minimum between two integer values. More...

#define	MAX(A, B) (((A) < (B)) ? (B) : (A))
	Obtain the maximum between two integer values. More...

#define	ABS(A) (((A) < 0) ? (-(A)) : (A))
	Obtain the absolute value of an integer. More...

#define	OFFSET_OF(M, T) ((size_t)(&(((T*)0)->M)))
	Get the offset of a member in a structure. More...

#define	CONTAINER_OF(P, M, T) ((T) ((uint8_t) (1 ? (P) : &(((T*)0)->M)) - OFFSET_OF(M, T)))
	Get a pointer to the structure T containing the member M pointed by P. More...

#define	NAME_OF(X) #X
	Convert the name of a symbol to a string. More...

#define	ELEMENTS_COUNT(X) ((size_t)(sizeof(X) / sizeof((X)[0])))
	Get the number of elements in a statically initialized array. More...

#define	DEPENDENCY_ON_MODULE(X) STATIC_ASSERT(LZ_CONFIG_MODULE_ ## X ## _USED, Module_ ## X ## _must_be_used)
	Perform a static assertion to check if a given module is activated. More...

Typedefs
typedef int	ptrdiff_t
	Represents the difference between two pointers.

typedef uint8_t	bool
	Boolean type.

typedef uint16_t	size_t
	Represents the size of an object.

typedef uint8_t	u_read_write_atomic_t
	Represents an unsigned integer that can be read and written atomically. More...

Detailed Description

Basic type definitions and useful macros.

Copyright: 2017-2020, Remi Andruccioli remi..nosp@m.andr.nosp@m.uccio.nosp@m.li@g.nosp@m.mail..nosp@m.com

This file describes basic type definitions and useful macros used in the Lazuli project.

Definition in file common.h.

Macro Definition Documentation

◆ UNUSED

#define UNUSED ( X ) ((void)(X))

Tell the compiler that the variable X is left unsed.

Parameters

X	The unused variable.

Definition at line 51 of file common.h.

◆ STATIC_ASSERT

#define STATIC_ASSERT	(	C,
		M
	)	extern char _static_assertion_##M[(C) ? 1 : -1]

Perform an assertion at compile time.

Won't compile if the assertion is false.

Parameters

C	The condition to check.
M	A C-language identifier used as "message/name" for the static assertion. It's used here to display an informative message directly in the source code and compiler output in case of a failure.

Definition at line 63 of file common.h.

◆ ALLOW_ARITHM

#define ALLOW_ARITHM ( X ) ((uint8_t *)(X))

Allow arithmetic on a void pointer.

Arithmetic on void pointers isn't allowed in standard C.

Parameters

X	The void pointer on which to perform arithmetic.

Definition at line 116 of file common.h.

◆ STATIC_CHECK_TYPE

#define STATIC_CHECK_TYPE	(	V,
		T
	)	UNUSED(1 ? (T*)0 : &(V))

Check that the lvalue V is of type T at compile time.

Parameters

V	The lvalue to check.
T	The supposed type of the lvalue.

Definition at line 134 of file common.h.

◆ SET_BITS

#define SET_BITS	(	V,
		T,
		X
	)

Value:

do {                                              \
    STATIC_CHECK_TYPE(V, T);                        \
    (V) |= (T)(X);                                  \
  } while (0)

Set the corresponding bits of X in the value V of type T.

Parameters

V	The value to set bits.
T	The type of the value V.
X	A value containing the bits (at logical 1) to set.

Definition at line 143 of file common.h.

◆ CLEAR_BITS

#define CLEAR_BITS	(	V,
		T,
		X
	)

Value:

do {                                          \
    STATIC_CHECK_TYPE(V, T);                    \
    (V) &= (T)(~(X));                           \
  } while (0)

Clear the corresponding bits of X in the value V of type T.

Parameters

V	The value to set bits.
T	The type of the value V.
X	A value containing the bits (at logical 1) to clear.

Definition at line 156 of file common.h.

◆ POSITION

#define POSITION ( X ) (1U << (X))

Define a constant bit at position X, starting from index 0.

Parameters

X	An unsigned integer constant representing the position of the bit, starting from index 0.

Warning: The constant must be specified using an unsigned integer litteral in uppercase. e.g. POSITION(2U) This is to make static analyzers not complain about using a shift operator with an unsigned value.

Definition at line 174 of file common.h.

◆ INDIRECT_T

#define INDIRECT_T	(	X,
		T
	)	((volatile T *)(X))

Define an indirect read/write variable at an absolute address.

i.e. A variable that is accessed through a pointer.

Parameters

X	The address of the variable.
T	The type of the variable.

Definition at line 183 of file common.h.

◆ INDIRECT

#define INDIRECT ( X ) INDIRECT_T(X, uint8_t)

Define an indirect read/write register at an absolute address.

i.e. A register that is accessed through a pointer.

Parameters

X	The address of the register.

Definition at line 191 of file common.h.

◆ DIRECT_T

#define DIRECT_T	(	X,
		T
	)	(*INDIRECT_T(X, T))

Define a direct read/write variable at an absolute address.

Parameters

X	The address of the variable.
T	The type of the variable.

Definition at line 199 of file common.h.

◆ DIRECT

#define DIRECT ( X ) DIRECT_T(X, uint8_t)

Define a direct read/write register at an absolute address.

Parameters

X	The address of the register.

Definition at line 206 of file common.h.

◆ LO8

#define LO8 ( X ) ((uint8_t)(X))

Take the low byte of a 16-bit value.

Parameters

X	The 16-bit value.

Definition at line 213 of file common.h.

◆ HI8

#define HI8 ( X ) LO8((X) >> 8U)

Take the high byte of a 16-bit value.

Parameters

X	The 16-bit value.

Definition at line 220 of file common.h.

◆ MIN

#define MIN	(	A,
		B
	)	(((A) < (B)) ? (A) : (B))

Obtain the minimum between two integer values.

Parameters

A	The first value.
B	The second value.

Definition at line 228 of file common.h.

◆ MAX

#define MAX	(	A,
		B
	)	(((A) < (B)) ? (B) : (A))

Obtain the maximum between two integer values.

Parameters

A	The first value.
B	The second value.

Definition at line 236 of file common.h.

◆ ABS

#define ABS ( A ) (((A) < 0) ? (-(A)) : (A))

Obtain the absolute value of an integer.

Parameters

A	The integer value.

Definition at line 243 of file common.h.

◆ OFFSET_OF

#define OFFSET_OF	(	M,
		T
	)	((size_t)(&(((T*)0)->M)))

Get the offset of a member in a structure.

Parameters

M	The name of the member.
T	The type of the structure.

Definition at line 251 of file common.h.

◆ CONTAINER_OF

#define CONTAINER_OF	(	P,
		M,
		T
	)	((T) ((uint8_t) (1 ? (P) : &(((T*)0)->M)) - OFFSET_OF(M, T)))

Get a pointer to the structure T containing the member M pointed by P.

May not compile if P doesn't point to the type defined by M.

Parameters

P	The pointer to the member.
M	The name of the member.
T	The type of the structure.

Definition at line 263 of file common.h.

◆ NAME_OF

#define NAME_OF ( X ) #X

Convert the name of a symbol to a string.

Parameters

X	The symbol name to convert.

Definition at line 271 of file common.h.

◆ ELEMENTS_COUNT

#define ELEMENTS_COUNT ( X ) ((size_t)(sizeof(X) / sizeof((X)[0])))

Get the number of elements in a statically initialized array.

Parameters

X	The array variable.

Definition at line 278 of file common.h.

◆ DEPENDENCY_ON_MODULE

#define DEPENDENCY_ON_MODULE ( X ) STATIC_ASSERT(LZ_CONFIG_MODULE_ ## X ## _USED, Module_ ## X ## _must_be_used)

Perform a static assertion to check if a given module is activated.

Parameters

X	The module name, in uppercase.

Definition at line 285 of file common.h.

Typedef Documentation

◆ u_read_write_atomic_t

typedef uint8_t u_read_write_atomic_t

Represents an unsigned integer that can be read and written atomically.

This type is the equivalent of libc's sig_atomic_t (signal.h).

Use this type with volatile.

Definition at line 107 of file common.h.

Macros

Typedefs

Detailed Description

Macro Definition Documentation

◆ UNUSED

◆ STATIC_ASSERT

◆ ALLOW_ARITHM

◆ STATIC_CHECK_TYPE

◆ SET_BITS

◆ CLEAR_BITS

◆ POSITION

◆ INDIRECT_T

◆ INDIRECT

◆ DIRECT_T

◆ DIRECT

◆ LO8

◆ HI8

◆ MIN

◆ MAX

◆ ABS

◆ OFFSET_OF

◆ CONTAINER_OF

◆ NAME_OF

◆ ELEMENTS_COUNT

◆ DEPENDENCY_ON_MODULE

Typedef Documentation

◆ u_read_write_atomic_t