util-atomic.h File Reference

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Macros
#define	SC_ATOMIC_DECLARE(type, name)
	wrapper to declare an atomic variable including a (spin) lock to protect it. More...
#define	SC_ATOMIC_EXTERN(type, name)
	wrapper to reference an atomic variable already declared on another file (including the spin lock) More...
#define	SC_ATOMIC_DECL_AND_INIT(type, name)
	wrapper to declare an atomic variable including a (spin) lock to protect it and initialize them. More...
#define	SC_ATOMIC_INIT(name)
	Initialize the previously declared atomic variable and it's lock. More...
#define	SC_ATOMIC_RESET(name)
	Initialize the previously declared atomic variable and it's lock. More...
#define	SC_ATOMIC_DESTROY(name)
	Destroy the lock used to protect this variable. More...
#define	SC_ATOMIC_ADD(name, val)
	add a value to our atomic variable More...
#define	SC_ATOMIC_SUB(name, val)
	sub a value from our atomic variable More...
#define	SC_ATOMIC_AND(name, val)
	Bitwise AND a value from our atomic variable. More...
#define	SC_ATOMIC_OR(name, val)
	Bitwise OR a value from our atomic variable. More...
#define	SC_ATOMIC_NAND(name, val)
	Bitwise NAND a value from our atomic variable. More...
#define	SC_ATOMIC_XOR(name, val)
	Bitwise XOR a value from our atomic variable. More...
#define	SC_ATOMIC_GET(name)
	Get the value from the atomic variable. More...
#define	SC_ATOMIC_SET(name, val)
	Set the value for the atomic variable. More...
#define	SC_ATOMIC_CAS(name, cmpval, newval)
	atomic Compare and Switch More...

Functions
void	SCAtomicRegisterTests (void)

Detailed Description

Author

Victor Julien victo.nosp@m.r@in.nosp@m.linia.nosp@m.c.ne.nosp@m.t

Pablo Rincon pablo.nosp@m..rin.nosp@m.con.c.nosp@m.resp.nosp@m.o@gma.nosp@m.il.c.nosp@m.om

API for atomic operations. Uses atomic instructions (GCC only at this time) where available, falls back to (spin)locked* operations otherwise.

To prevent developers from accidentally working with the atomic variables directly instead of through the proper macro's, a marco trick is performed that exposes different variable names than the developer uses. So if the dev uses "somevar", internally "somevar_sc_atomic__" is used.

Where available, we use sync_fetch_and_add and __sync_bool_compare_and_swap. If those are unavailable, the API transparently created a matching (spin)lock for each atomic variable. The lock will be named "somevar_sc_lock</strong>"

(*) where spinlocks are unavailable, the threading api falls back to mutex

Definition in file util-atomic.h.

Macro Definition Documentation

SC_ATOMIC_ADD

#define SC_ATOMIC_ADD	(		name,
			val
	)

Value:

    ({\
    typeof(name ## _sc_atomic__) var; \
    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) += (val); \
        var = (name ## _sc_atomic__); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0); \
    var ; \
})

add a value to our atomic variable

Parameters

name	the atomic variable
val	the value to add to the variable

Definition at line 107 of file util-atomic.h.

SC_ATOMIC_AND

#define SC_ATOMIC_AND	(		name,
			val
	)

Value:

    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) &= (val); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0)

Bitwise AND a value from our atomic variable.

Parameters

name	the atomic variable
val	the value to sub from the variable

Definition at line 141 of file util-atomic.h.

SC_ATOMIC_CAS

#define SC_ATOMIC_CAS	(		name,
			cmpval,
			newval
	)

Value:

    ({ \
    char r = 0; \
    do { \
        SCSpinLock((name ## _sc_lock__)); \
        if (*(name ## _sc_atomic__) == (cmpval)) { \
            *(name ## _sc_atomic__) = (newval); \
            r = 1; \
        } \
        SCSpinUnlock((name ## _sc_lock__)); \
    } while(0); \
    r; \
})

atomic Compare and Switch

Warning

"name" is passed to us as "&var"

Definition at line 222 of file util-atomic.h.

SC_ATOMIC_DECL_AND_INIT

#define SC_ATOMIC_DECL_AND_INIT	(		type,
			name
	)

Value:

    type name ## _sc_atomic__ = 0; \
    SCSpinlock name ## _sc_lock__; \
    SCSpinInit(&(name ## _sc_lock__), 0)

wrapper to declare an atomic variable including a (spin) lock to protect it and initialize them.

Definition at line 72 of file util-atomic.h.

SC_ATOMIC_DECLARE

#define SC_ATOMIC_DECLARE	(		type,
			name
	)

Value:

    type name ## _sc_atomic__; \
    SCSpinlock name ## _sc_lock__

wrapper to declare an atomic variable including a (spin) lock to protect it.

Warning

Variable and lock are not initialized.

Definition at line 56 of file util-atomic.h.

SC_ATOMIC_DESTROY

#define SC_ATOMIC_DESTROY

(

name

)

Value:

        do { \
        SCSpinDestroy(&(name ## _sc_lock__)); \
    } while (0)

Destroy the lock used to protect this variable.

Definition at line 97 of file util-atomic.h.

SC_ATOMIC_EXTERN

#define SC_ATOMIC_EXTERN	(		type,
			name
	)

Value:

    extern type name ## _sc_atomic__; \
    extern SCSpinlock name ## _sc_lock__

wrapper to reference an atomic variable already declared on another file (including the spin lock)

Definition at line 64 of file util-atomic.h.

SC_ATOMIC_GET

#define SC_ATOMIC_GET

(

name

)

Value:

    ({ \
    typeof(name ## _sc_atomic__) var; \
    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        var = (name ## _sc_atomic__); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while (0); \
    var; \
})

Get the value from the atomic variable.

Return values

var

value

Definition at line 192 of file util-atomic.h.

SC_ATOMIC_INIT

#define SC_ATOMIC_INIT

(

name

)

Value:

        do { \
        SCSpinInit(&(name ## _sc_lock__), 0); \
        (name ## _sc_atomic__) = 0; \
    } while(0)

Initialize the previously declared atomic variable and it's lock.

Definition at line 81 of file util-atomic.h.

SC_ATOMIC_NAND

#define SC_ATOMIC_NAND	(		name,
			val
	)

Value:

    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) = ~(name ## _sc_atomic__) & (val); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0)

Bitwise NAND a value from our atomic variable.

Parameters

name	the atomic variable
val	the value to sub from the variable

Definition at line 167 of file util-atomic.h.

SC_ATOMIC_OR

#define SC_ATOMIC_OR	(		name,
			val
	)

Value:

    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) |= (val); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0)

Bitwise OR a value from our atomic variable.

Parameters

name	the atomic variable
val	the value to sub from the variable

Definition at line 154 of file util-atomic.h.

SC_ATOMIC_RESET

#define SC_ATOMIC_RESET

(

name

)

Value:

        do { \
        (name ## _sc_atomic__) = 0; \
    } while(0)

Initialize the previously declared atomic variable and it's lock.

Definition at line 90 of file util-atomic.h.

SC_ATOMIC_SET

#define SC_ATOMIC_SET	(		name,
			val
	)

Value:

    ({       \
    typeof(name ## _sc_atomic__) var; \
    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        var = (name ## _sc_atomic__) = val; \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while (0); \
    var; \
})

Set the value for the atomic variable.

Return values

var

value

Definition at line 207 of file util-atomic.h.

SC_ATOMIC_SUB

#define SC_ATOMIC_SUB	(		name,
			val
	)

Value:

    ({ \
    typeof(name ## _sc_atomic__) var; \
    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) -= (val); \
        var = (name ## _sc_atomic__); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0); \
    var ; \
})

sub a value from our atomic variable

Parameters

name	the atomic variable
val	the value to sub from the variable

Definition at line 124 of file util-atomic.h.

SC_ATOMIC_XOR

#define SC_ATOMIC_XOR	(		name,
			val
	)

Value:

    do { \
        SCSpinLock(&(name ## _sc_lock__)); \
        (name ## _sc_atomic__) ^= (val); \
        SCSpinUnlock(&(name ## _sc_lock__)); \
    } while(0)

Bitwise XOR a value from our atomic variable.

Parameters

name	the atomic variable
val	the value to sub from the variable

Definition at line 180 of file util-atomic.h.

Function Documentation

SCAtomicRegisterTests()

void SCAtomicRegisterTests

(

void

)

Definition at line 66 of file util-atomic.c.

References UtRegisterTest().

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