atomic.h File Reference

Atomic functions. More...

#include <stdint.h>

Include dependency graph for atomic.h:

Functions
const char *	cmx_atomic_implementation_name ()
	current implementation
Get/Set operations
Get and set on volatile casted pointers.
uint16_t	cmx_atomic_read_uint16 (volatile const uint16_t *ptr)
	Reads the value of type uint16_t at 'ptr'.
void	cmx_atomic_set_uint16 (volatile uint16_t *ptr, uint16_t val)
	Sets memory of type uint16_t at 'ptr' to value 'val'.
int32_t	cmx_atomic_read_int32 (volatile const int32_t *ptr)
	Reads the value of type int32_t at 'ptr'.
void	cmx_atomic_set_int32 (volatile int32_t *ptr, int32_t val)
	Sets memory of type int32_t at 'ptr' to value 'val'.
uint64_t	cmx_atomic_read_uint64 (volatile const uint64_t *ptr)
	Reads the value of type uint16_t at 'ptr'.
void	cmx_atomic_set_uint64 (volatile uint64_t *ptr, uint64_t val)
	Sets memory of type uint16_t at 'ptr' to value 'val'.
Atomic operations
Functions wrapping atomic operations.
int32_t	cmx_atomic_val_compare_and_swap_int32 (volatile int32_t *ptr, int32_t oldval, int32_t newval)
	CAS for a int32_t value.
Memory barriers.
Functions to generate memory barriers.
void	cmx_atomic_smp_mb ()
	Insert a full memory barrier.
void	cmx_atomic_smp_rmb ()
	Insert a read memory barrier.
void	cmx_atomic_smp_wmb ()
	Insert a write memory barrier.

---

Detailed Description

Atomic functions.

For reference see:

• Linux Kernel: arch/x86/include/asm/barrier.h
• Apache portable runtime (http://apr.apache.org/): atomic/unix/ia32.c
• Intel Documentation http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html
• AMD Documentation http://developer.amd.com/resources/documentation-articles/developer-guides-manuals/
• Herlihy, The Art of Multiprocessor Programming, p. 478.

---

Function Documentation

const char* cmx_atomic_implementation_name

(

)

current implementation

Name of the implementation selected at compile-time.

Note:

This function may return empty string if gcc-builtin is used for all targets in future.

Returns:

the name of the atomic implementation

int32_t cmx_atomic_read_int32

(

volatile const int32_t *

ptr

)

Reads the value of type int32_t at 'ptr'.

No memory barrier is generated by this function.

Returns:

The value read at 'ptr'.

uint16_t cmx_atomic_read_uint16

(

volatile const uint16_t *

ptr

)

Reads the value of type uint16_t at 'ptr'.

See also:

cmx_atomic_read_int32()

uint64_t cmx_atomic_read_uint64

(

volatile const uint64_t *

ptr

)

Reads the value of type uint16_t at 'ptr'.

See also:

cmx_atomic_read_int32()

void cmx_atomic_set_int32	(	volatile int32_t *	ptr,
		int32_t	val
	)

Sets memory of type int32_t at 'ptr' to value 'val'.

No memory barrier generated by this function.

void cmx_atomic_set_uint16	(	volatile uint16_t *	ptr,
		uint16_t	val
	)

Sets memory of type uint16_t at 'ptr' to value 'val'.

See also:

cmx_atomic_set_int32()

void cmx_atomic_set_uint64	(	volatile uint64_t *	ptr,
		uint64_t	val
	)

Sets memory of type uint16_t at 'ptr' to value 'val'.

See also:

cmx_atomic_set_int32()

int32_t cmx_atomic_val_compare_and_swap_int32	(	volatile int32_t *	ptr,
		int32_t	oldval,
		int32_t	newval
	)

CAS for a int32_t value.

Compare a int32_t value pointed to by 'ptr' with 'oldval'. If they are the same, swap the value with 'newval'. returns always the value pointed to by 'ptr' before the operation.

A successful operation is: compare_and_swap(&val, oldval, newval) == oldval

Parameters:

	ptr	pointer to the value
	oldval	what to swap it with
	newval	the value to compare it to

Returns:

the old value of *ptr

Here is the caller graph for this function: