Atomic

Atomic 的协作图:

函数
STATIC INLINE INT32	LOS_AtomicRead (const Atomic *v)
	Atomic read. | 读取32bit原子数据 更多...
STATIC INLINE VOID	LOS_AtomicSet (Atomic *v, INT32 setVal)
	Atomic setting. 更多...
STATIC INLINE INT32	LOS_AtomicAdd (Atomic *v, INT32 addVal)
	Atomic addition. 更多...
STATIC INLINE INT32	LOS_AtomicSub (Atomic *v, INT32 subVal)
	Atomic subtraction. 更多...
STATIC INLINE VOID	LOS_AtomicInc (Atomic *v)
	Atomic addSelf. 更多...
STATIC INLINE INT32	LOS_AtomicIncRet (Atomic *v)
	Atomic addSelf. | 对内存数据加1并返回运算结果 更多...
STATIC INLINE VOID	LOS_AtomicDec (Atomic *v)
	Atomic auto-decrement. | 对32bit原子数据做减1 更多...
STATIC INLINE INT32	LOS_AtomicDecRet (Atomic *v)
	Atomic auto-decrement. | 对内存数据减1并返回运算结果 更多...
STATIC INLINE INT64	LOS_Atomic64Read (const Atomic64 *v)
	Atomic64 read. | 读取64bit原子数据 更多...
STATIC INLINE VOID	LOS_Atomic64Set (Atomic64 *v, INT64 setVal)
	Atomic64 setting. | 写入64位内存数据 更多...
STATIC INLINE INT64	LOS_Atomic64Add (Atomic64 *v, INT64 addVal)
	Atomic64 addition. | 对64位内存数据做加法 更多...
STATIC INLINE INT64	LOS_Atomic64Sub (Atomic64 *v, INT64 subVal)
	Atomic64 subtraction. | 对64位原子数据做减法 更多...
STATIC INLINE VOID	LOS_Atomic64Inc (Atomic64 *v)
	Atomic64 addSelf. | 对64位原子数据加1 更多...
STATIC INLINE INT64	LOS_Atomic64IncRet (Atomic64 *v)
	Atomic64 addSelf. | 对64位原子数据加1并返回运算结果 更多...
STATIC INLINE VOID	LOS_Atomic64Dec (Atomic64 *v)
	Atomic64 auto-decrement. | 对64位原子数据减1 更多...
STATIC INLINE INT64	LOS_Atomic64DecRet (Atomic64 *v)
	Atomic64 auto-decrement. | 对64位原子数据减1并返回运算结果 更多...
STATIC INLINE INT32	LOS_AtomicXchgByte (volatile INT8 *v, INT32 val)
	Atomic exchange for 8-bit variable. | 交换8位原子数据，原内存中的值以返回值的方式返回 更多...
STATIC INLINE INT32	LOS_AtomicXchg16bits (volatile INT16 *v, INT32 val)
	Atomic exchange for 16-bit variable. | 交换16位原子数据，原内存中的值以返回值的方式返回 更多...
STATIC INLINE INT32	LOS_AtomicXchg32bits (Atomic *v, INT32 val)
	Atomic exchange for 32-bit variable. | 交换32位原子数据，原内存中的值以返回值的方式返回 更多...
STATIC INLINE INT64	LOS_AtomicXchg64bits (Atomic64 *v, INT64 val)
	Atomic exchange for 64-bit variable. | 交换64位原子数据，原内存中的值以返回值的方式返回 更多...
STATIC INLINE BOOL	LOS_AtomicCmpXchgByte (volatile INT8 *v, INT32 val, INT32 oldVal)
	Atomic exchange for 8-bit variable with compare. | 比较并交换8位原子数据，返回比较结果 更多...
STATIC INLINE BOOL	LOS_AtomicCmpXchg16bits (volatile INT16 *v, INT32 val, INT32 oldVal)
	Atomic exchange for 16-bit variable with compare. | 比较并交换16位原子数据，返回比较结果 更多...
STATIC INLINE BOOL	LOS_AtomicCmpXchg32bits (Atomic *v, INT32 val, INT32 oldVal)
	Atomic exchange for 32-bit variable with compare. | 比较并交换32位原子数据，返回比较结果 更多...
STATIC INLINE BOOL	LOS_AtomicCmpXchg64bits (Atomic64 *v, INT64 val, INT64 oldVal)
	Atomic exchange for 64-bit variable with compare. | 比较并交换64位原子数据，返回比较结果 更多...

详细描述

函数说明

LOS_Atomic64Add()

STATIC INLINE INT64 LOS_Atomic64Add	(	Atomic64 *	v,
		INT64	addVal
	)

Atomic64 addition. | 对64位内存数据做加法

Description:

This API is used to implement the atomic64 addition and return the result value of the augend.

注意

• The pointer v must not be NULL.
• If the addtion result is not in the range of representable values for 64-bit signed integer, an int integer overflow may occur to the return value

参数

v	[IN] The augend pointer.
addVal	[IN] The addend.

返回值

INT64

The result value of the augend.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 460 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %1, %H1, [%2]\n"
                             "adds   %Q1, %Q1, %Q3\n"
                             "adc   %R1, %R1, %R3\n"
                             "strexd   %0, %1, %H1, [%2]"
                             : "=&r"(status), "=&r"(val)
                             : "r"(v), "r"(addVal)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

LOS_Atomic64Dec()

STATIC INLINE VOID LOS_Atomic64Dec

(

Atomic64 *

v

)

Atomic64 auto-decrement. | 对64位原子数据减1

Description:

This API is used to implementating the atomic64 auto-decrement.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT64_MIN to avoid overflow after reducing 1.

参数

v	[IN] The auto-decrement variable pointer.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 608 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "subs   %Q0, %Q0, #1\n"
                             "sbc   %R0, %R0, #0\n"
                             "strexd   %1, %0, %H0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
}

LOS_Atomic64DecRet()

STATIC INLINE INT64 LOS_Atomic64DecRet

(

Atomic64 *

v

)

Atomic64 auto-decrement. | 对64位原子数据减1并返回运算结果

Description:

This API is used to implementating the atomic64 auto-decrement and return the result of auto-decrement.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT64_MIN to avoid overflow after reducing 1.

参数

v	[IN] The auto-decrement variable pointer.

返回值

INT64

The return value of variable auto-decrement.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 643 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "subs   %Q0, %Q0, #1\n"
                             "sbc   %R0, %R0, #0\n"
                             "strexd   %1, %0, %H0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

LOS_Atomic64Inc()

STATIC INLINE VOID LOS_Atomic64Inc

(

Atomic64 *

v

)

Atomic64 addSelf. | 对64位原子数据加1

Description:

This API is used to implement the atomic64 addSelf .

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT64_MAX to avoid integer overflow after adding 1.

参数

v	[IN] The addSelf variable pointer.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 536 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "adds   %Q0, %Q0, #1\n"
                             "adc   %R0, %R0, #0\n"
                             "strexd   %1, %0, %H0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
}

LOS_Atomic64IncRet()

STATIC INLINE INT64 LOS_Atomic64IncRet

(

Atomic64 *

v

)

Atomic64 addSelf. | 对64位原子数据加1并返回运算结果

Description:

This API is used to implement the atomic64 addSelf and return the result of addSelf.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT64_MAX to avoid integer overflow after adding 1.

参数

v	[IN] The addSelf variable pointer.

返回值

INT64

The return value of variable addSelf.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 571 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "adds   %Q0, %Q0, #1\n"
                             "adc   %R0, %R0, #0\n"
                             "strexd   %1, %0, %H0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

LOS_Atomic64Read()

STATIC INLINE INT64 LOS_Atomic64Read

(

const Atomic64 *

v

)

Atomic64 read. | 读取64bit原子数据

Description:

This API is used to implement the atomic64 read and return the result value of the read.

注意

• The pointer v must not be NULL.

参数

v	[IN] The reading pointer.

返回值

INT64

The result value of the read.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 392 行定义.

{
    INT64 val;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%1]"
                             : "=&r"(val)
                             : "r"(v)
                             : "cc");
    } while (0);
 
    return val;
}

LOS_Atomic64Set()

STATIC INLINE VOID LOS_Atomic64Set	(	Atomic64 *	v,
		INT64	setVal
	)

Atomic64 setting. | 写入64位内存数据

Description:

This API is used to implement the atomic64 setting operation.

注意

• The pointer v must not be NULL.

参数

v	[IN] The variable pointer to be setting.
setVal	[IN] The value to be setting.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 425 行定义.

{
    INT64 tmp;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %1, %H1, [%2]\n"
                             "strexd   %0, %3, %H3, [%2]"
                             : "=&r"(status), "=&r"(tmp)
                             : "r"(v), "r"(setVal)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
}

LOS_Atomic64Sub()

STATIC INLINE INT64 LOS_Atomic64Sub	(	Atomic64 *	v,
		INT64	subVal
	)

Atomic64 subtraction. | 对64位原子数据做减法

Description:

This API is used to implement the atomic64 subtraction and return the result value of the minuend.

注意

• The pointer v must not be NULL.
• If the subtraction result is not in the range of representable values for 64-bit signed integer, an int integer overflow may occur to the return value

参数

v	[IN] The minuend pointer.
subVal	[IN] The subtrahend.

返回值

INT64

The result value of the minuend.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 499 行定义.

{
    INT64 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %1, %H1, [%2]\n"
                             "subs   %Q1, %Q1, %Q3\n"
                             "sbc   %R1, %R1, %R3\n"
                             "strexd   %0, %1, %H1, [%2]"
                             : "=&r"(status), "=&r"(val)
                             : "r"(v), "r"(subVal)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

LOS_AtomicAdd()

STATIC INLINE INT32 LOS_AtomicAdd	(	Atomic *	v,
		INT32	addVal
	)

Atomic addition.

Description:

This API is used to implement the atomic addition and return the result value of the augend.

注意

• The pointer v must not be NULL.
• If the addtion result is not in the range of representable values for 32-bit signed integer, an int integer overflow may occur to the return value

参数

v	[IN] The augend pointer.
addVal	[IN] The addend.

返回值

INT32

The result value of the augend.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 173 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %1, [%2]\n"
                             "add   %1, %1, %3\n"
                             "strex   %0, %1, [%2]"
                             : "=&r"(status), "=&r"(val)
                             : "r"(v), "r"(addVal)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
    /****************************************************
    __builtin_expect是结束循环的判断语句，将最有可能执行的分支告诉编译器。
    这个指令的写法为：__builtin_expect(EXP， N)。
    意思是：EXP==N 的概率很大。
    综合理解__builtin_expect(status != 0， 0)
    说的是status = 0 的可能性很大，不成功就会重新来一遍，直到strex更新成(status == 0)为止.
    ****************************************************/
    return val;
}

这是这个函数的调用关系图:

LOS_AtomicCmpXchg16bits()

STATIC INLINE BOOL LOS_AtomicCmpXchg16bits	(	volatile INT16 *	v,
		INT32	val,
		INT32	oldVal
	)

Atomic exchange for 16-bit variable with compare. | 比较并交换16位原子数据，返回比较结果

Description:

This API is used to implement the atomic exchange for 16-bit variable, if the value of variable is equal to oldVal.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The new value.
oldVal	[IN] The old value.

返回值

TRUE	The previous value of the atomic variable is not equal to oldVal.
FALSE	The previous value of the atomic variable is equal to oldVal.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 853 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexh %0, [%3]\n"
                             "mov %1, #0\n"
                             "teq %0, %4\n"
                             "strexheq %1, %5, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(oldVal), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal != oldVal;
}

LOS_AtomicCmpXchg32bits()

STATIC INLINE BOOL LOS_AtomicCmpXchg32bits	(	Atomic *	v,
		INT32	val,
		INT32	oldVal
	)

Atomic exchange for 32-bit variable with compare. | 比较并交换32位原子数据，返回比较结果

Description:

This API is used to implement the atomic exchange for 32-bit variable, if the value of variable is equal to oldVal.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The new value.
oldVal	[IN] The old value.

返回值

TRUE	The previous value of the atomic variable is not equal to oldVal.
FALSE	The previous value of the atomic variable is equal to oldVal.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 890 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex %0, [%3]\n"
                             "mov %1, #0\n"
                             "teq %0, %4\n"
                             "strexeq %1, %5, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(oldVal), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal != oldVal;
}

这是这个函数的调用关系图:

LOS_AtomicCmpXchg64bits()

STATIC INLINE BOOL LOS_AtomicCmpXchg64bits	(	Atomic64 *	v,
		INT64	val,
		INT64	oldVal
	)

Atomic exchange for 64-bit variable with compare. | 比较并交换64位原子数据，返回比较结果

Description:

This API is used to implement the atomic exchange for 64-bit variable, if the value of variable is equal to oldVal.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The new value.
oldVal	[IN] The old value.

返回值

TRUE	The previous value of the atomic variable is not equal to oldVal.
FALSE	The previous value of the atomic variable is equal to oldVal.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 927 行定义.

{
    INT64 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "mov   %1, #0\n"
                             "teq   %0, %4\n"
                             "teqeq   %H0, %H4\n"
                             "strexdeq   %1, %5, %H5, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(oldVal), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal != oldVal;
}

LOS_AtomicCmpXchgByte()

STATIC INLINE BOOL LOS_AtomicCmpXchgByte	(	volatile INT8 *	v,
		INT32	val,
		INT32	oldVal
	)

Atomic exchange for 8-bit variable with compare. | 比较并交换8位原子数据，返回比较结果

Description:

This API is used to implement the atomic exchange for 8-bit variable, if the value of variable is equal to oldVal.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The new value.
oldVal	[IN] The old value.

返回值

TRUE	The previous value of the atomic variable is not equal to oldVal.
FALSE	The previous value of the atomic variable is equal to oldVal.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 816 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexb %0, [%3]\n"
                             "mov %1, #0\n"
                             "teq %0, %4\n"
                             "strexbeq %1, %5, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(oldVal), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal != oldVal;
}

LOS_AtomicDec()

STATIC INLINE VOID LOS_AtomicDec

(

Atomic *

v

)

Atomic auto-decrement. | 对32bit原子数据做减1

Description:

This API is used to implementating the atomic auto-decrement.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT_MIN to avoid overflow after reducing 1.

参数

v	[IN] The auto-decrement variable pointer.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 323 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %0, [%3]\n"
                             "sub   %0, %0, #1\n"
                             "strex   %1, %0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
}

这是这个函数的调用关系图:

LOS_AtomicDecRet()

STATIC INLINE INT32 LOS_AtomicDecRet

(

Atomic *

v

)

Atomic auto-decrement. | 对内存数据减1并返回运算结果

Description:

This API is used to implementating the atomic auto-decrement and return the result of auto-decrement.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT_MIN to avoid overflow after reducing 1.

参数

v	[IN] The auto-decrement variable pointer.

返回值

INT32

The return value of variable auto-decrement.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 357 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %0, [%3]\n"
                             "sub   %0, %0, #1\n"
                             "strex   %1, %0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

这是这个函数的调用关系图:

LOS_AtomicInc()

STATIC INLINE VOID LOS_AtomicInc

(

Atomic *

v

)

Atomic addSelf.

Description:

This API is used to implement the atomic addSelf.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT_MAX to avoid integer overflow after adding 1.

参数

v	[IN] The addSelf variable pointer.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 253 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %0, [%3]\n"
                             "add   %0, %0, #1\n"
                             "strex   %1, %0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
}

这是这个函数的调用关系图:

LOS_AtomicIncRet()

STATIC INLINE INT32 LOS_AtomicIncRet

(

Atomic *

v

)

Atomic addSelf. | 对内存数据加1并返回运算结果

Description:

This API is used to implement the atomic addSelf and return the result of addSelf.

注意

• The pointer v must not be NULL.
• The value which v point to must not be INT_MAX to avoid integer overflow after adding 1.

参数

v	[IN] The addSelf variable pointer.

返回值

INT32

The return value of variable addSelf.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 287 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %0, [%3]\n"
                             "add   %0, %0, #1\n"
                             "strex   %1, %0, [%3]"
                             : "=&r"(val), "=&r"(status), "+m"(*v)
                             : "r"(v)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

LOS_AtomicRead()

STATIC INLINE INT32 LOS_AtomicRead

(

const Atomic *

v

)

Atomic read. | 读取32bit原子数据

Description:

This API is used to implement the atomic read and return the result value of the read.

注意

• The pointer v must not be NULL.

参数

v	[IN] The reading pointer.

返回值

INT32

The result value of the read.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 123 行定义.

{
    return *(volatile INT32 *)v;    //读取内存数据
}

这是这个函数的调用关系图:

LOS_AtomicSet()

STATIC INLINE VOID LOS_AtomicSet	(	Atomic *	v,
		INT32	setVal
	)

Atomic setting.

Description:

This API is used to implement the atomic setting operation.

注意

• The pointer v must not be NULL.

参数

v	[IN] The variable pointer to be setting.
setVal	[IN] The value to be setting.

返回值

none.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 147 行定义.

{
    *(volatile INT32 *)v = setVal;
}

这是这个函数的调用关系图:

LOS_AtomicSub()

STATIC INLINE INT32 LOS_AtomicSub	(	Atomic *	v,
		INT32	subVal
	)

Atomic subtraction.

Description:

This API is used to implement the atomic subtraction and return the result value of the minuend.

注意

• The pointer v must not be NULL.
• If the subtraction result is not in the range of representable values for 32-bit signed integer, an int integer overflow may occur to the return value

参数

v	[IN] The minuend pointer.
subVal	[IN] The subtrahend.

返回值

INT32

The result value of the minuend.

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 217 行定义.

{
    INT32 val;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %1, [%2]\n"
                             "sub   %1, %1, %3\n"
                             "strex   %0, %1, [%2]"
                             : "=&r"(status), "=&r"(val)
                             : "r"(v), "r"(subVal)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return val;
}

这是这个函数的调用关系图:

LOS_AtomicXchg16bits()

STATIC INLINE INT32 LOS_AtomicXchg16bits	(	volatile INT16 *	v,
		INT32	val
	)

Atomic exchange for 16-bit variable. | 交换16位原子数据，原内存中的值以返回值的方式返回

Description:

This API is used to implement the atomic exchange for 16-bit variable and return the previous value of the atomic variable.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The exchange value.

返回值

INT32

The previous value of the atomic variable

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 713 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexh   %0, [%3]\n"
                             "strexh   %1, %4, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal;
}

LOS_AtomicXchg32bits()

STATIC INLINE INT32 LOS_AtomicXchg32bits	(	Atomic *	v,
		INT32	val
	)

Atomic exchange for 32-bit variable. | 交换32位原子数据，原内存中的值以返回值的方式返回

Description:

This API is used to implement the atomic exchange for 32-bit variable and return the previous value of the atomic variable.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The exchange value.

返回值

INT32

The previous value of the atomic variable

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 747 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrex   %0, [%3]\n"
                             "strex   %1, %4, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal;
}

LOS_AtomicXchg64bits()

STATIC INLINE INT64 LOS_AtomicXchg64bits	(	Atomic64 *	v,
		INT64	val
	)

Atomic exchange for 64-bit variable. | 交换64位原子数据，原内存中的值以返回值的方式返回

Description:

This API is used to implement the atomic exchange for 64-bit variable and return the previous value of the atomic variable.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The exchange value.

返回值

INT64

The previous value of the atomic variable

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 781 行定义.

{
    INT64 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexd   %0, %H0, [%3]\n"
                             "strexd   %1, %4, %H4, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal;
}

LOS_AtomicXchgByte()

STATIC INLINE INT32 LOS_AtomicXchgByte	(	volatile INT8 *	v,
		INT32	val
	)

Atomic exchange for 8-bit variable. | 交换8位原子数据，原内存中的值以返回值的方式返回

Description:

This API is used to implement the atomic exchange for 8-bit variable and return the previous value of the atomic variable.

注意

pointer v must not be NULL.

参数

v	[IN] The variable pointer.
val	[IN] The exchange value.

返回值

INT32

The previous value of the atomic variable

Dependency:

• los_atomic.h: the header file that contains the API declaration.

参见

在文件 los_atomic.h 第 679 行定义.

{
    INT32 prevVal;
    UINT32 status;
 
    do {
        __asm__ __volatile__("ldrexb   %0, [%3]\n"
                             "strexb   %1, %4, [%3]"
                             : "=&r"(prevVal), "=&r"(status), "+m"(*v)
                             : "r"(v), "r"(val)
                             : "cc");
    } while (__builtin_expect(status != 0, 0));
 
    return prevVal;
}