[ltt-dev] [PATCH 2/2] introduce uatomic_and and uatomic_or

[Mathieu Desnoyers]

* Paolo Bonzini (pbonzini at redhat.com) wrote:
> These are useful to flip single bits.

I'm trying to figure out the semantic of these operations.

are they

uatomic_add / uatomic_or or uatomic_add_return / uatomic_or_return ?

Thanks,

Mathieu

> 
> Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
> ---
>  tests/test_uatomic.c   |    6 ++
>  urcu/uatomic_generic.h |  220 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 226 insertions(+), 0 deletions(-)
> 
> diff --git a/tests/test_uatomic.c b/tests/test_uatomic.c
> index 5682655..f14ed56 100644
> --- a/tests/test_uatomic.c
> +++ b/tests/test_uatomic.c
> @@ -39,6 +39,12 @@ do {						\
>  	v = uatomic_sub_return(ptr, 1);		\
>  	assert(v == 121);			\
>  	assert(uatomic_read(ptr) == 121);	\
> +	v = uatomic_and(ptr, 0x47);		\
> +	assert(v == 121);			\
> +	assert(uatomic_read(ptr) == 0x41);	\
> +	v = uatomic_or(ptr, 120);		\
> +	assert(v == 0x41);			\
> +	assert(uatomic_read(ptr) == 121);	\
>  } while (0)
>  
>  int main(int argc, char **argv)
> diff --git a/urcu/uatomic_generic.h b/urcu/uatomic_generic.h
> index 383ddfa..7f3bc00 100644
> --- a/urcu/uatomic_generic.h
> +++ b/urcu/uatomic_generic.h
> @@ -87,6 +87,74 @@ unsigned long _uatomic_cmpxchg(void *addr, unsigned long old,
>  						sizeof(*(addr))))
>  
>  
> +/* uatomic_and */
> +
> +#ifndef uatomic_and
> +static inline __attribute__((always_inline))
> +unsigned long _uatomic_and(void *addr, unsigned long val,
> +				 int len)
> +{
> +	switch (len) {
> +#ifdef UATOMIC_HAS_ATOMIC_BYTE
> +	case 1:
> +		return __sync_fetch_and_and_1(addr, val);
> +#endif
> +#ifdef UATOMIC_HAS_ATOMIC_SHORT
> +	case 2:
> +		return __sync_fetch_and_and_2(addr, val);
> +#endif
> +	case 4:
> +		return __sync_fetch_and_and_4(addr, val);
> +#if (BITS_PER_LONG == 64)
> +	case 8:
> +		return __sync_fetch_and_and_8(addr, val);
> +#endif
> +	}
> +	_uatomic_link_error();
> +	return 0;
> +}
> +
> +
> +#define uatomic_and(addr, v)					\
> +	((__typeof__(*(addr))) _uatomic_and((addr),		\
> +					    (unsigned long)(v),	\
> +					    sizeof(*(addr))))
> +#endif /* #ifndef uatomic_and */
> +
> +/* uatomic_or */
> +
> +#ifndef uatomic_or
> +static inline __attribute__((always_inline))
> +unsigned long _uatomic_or(void *addr, unsigned long val,
> +				 int len)
> +{
> +	switch (len) {
> +#ifdef UATOMIC_HAS_ATOMIC_BYTE
> +	case 1:
> +		return __sync_fetch_and_or_1(addr, val);
> +#endif
> +#ifdef UATOMIC_HAS_ATOMIC_SHORT
> +	case 2:
> +		return __sync_fetch_and_or_2(addr, val);
> +#endif
> +	case 4:
> +		return __sync_fetch_and_or_4(addr, val);
> +#if (BITS_PER_LONG == 64)
> +	case 8:
> +		return __sync_fetch_and_or_8(addr, val);
> +#endif
> +	}
> +	_uatomic_link_error();
> +	return 0;
> +}
> +
> +
> +#define uatomic_or(addr, v)					\
> +	((__typeof__(*(addr))) _uatomic_or((addr),		\
> +					   (unsigned long)(v),	\
> +					   sizeof(*(addr))))
> +#endif /* #ifndef uatomic_or */
> +
>  /* uatomic_add_return */
>  
>  #ifndef uatomic_add_return
> @@ -186,6 +254,158 @@ unsigned long _uatomic_exchange(void *addr, unsigned long val, int len)
>  
>  #else /* #ifndef uatomic_cmpxchg */
>  
> +#ifndef uatomic_and
> +/* uatomic_and */
> +
> +static inline __attribute__((always_inline))
> +unsigned long _uatomic_and(void *addr, unsigned long val, int len)
> +{
> +	switch (len) {
> +#ifdef UATOMIC_HAS_ATOMIC_BYTE
> +	case 1:
> +	{
> +		unsigned char old, oldt;
> +
> +		oldt = uatomic_read((unsigned char *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned char *)addr,
> +                                               old, old & val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +#ifdef UATOMIC_HAS_ATOMIC_SHORT
> +	case 2:
> +	{
> +		unsigned short old, oldt;
> +
> +		oldt = uatomic_read((unsigned short *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned short *)addr,
> +                                               old, old & val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +	case 4:
> +	{
> +		unsigned int old, oldt;
> +
> +		oldt = uatomic_read((unsigned int *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned int *)addr,
> +                                               old, old & val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#if (BITS_PER_LONG == 64)
> +	case 8:
> +	{
> +		unsigned long old, oldt;
> +
> +		oldt = uatomic_read((unsigned long *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned long *)addr,
> +                                               old, old & val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +	}
> +	_uatomic_link_error();
> +	return 0;
> +}
> +
> +#define uatomic_and(addr, v)					\
> +	((__typeof__(*(addr))) _uatomic_and((addr),		\
> +					    (unsigned long)(v),	\
> +					    sizeof(*(addr))))
> +#endif /* #ifndef uatomic_and */
> +
> +#ifndef uatomic_or
> +/* uatomic_or */
> +
> +static inline __attribute__((always_inline))
> +unsigned long _uatomic_or(void *addr, unsigned long val, int len)
> +{
> +	switch (len) {
> +#ifdef UATOMIC_HAS_ATOMIC_BYTE
> +	case 1:
> +	{
> +		unsigned char old, oldt;
> +
> +		oldt = uatomic_read((unsigned char *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned char *)addr,
> +                                               old, old | val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +#ifdef UATOMIC_HAS_ATOMIC_SHORT
> +	case 2:
> +	{
> +		unsigned short old, oldt;
> +
> +		oldt = uatomic_read((unsigned short *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned short *)addr,
> +                                               old, old | val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +	case 4:
> +	{
> +		unsigned int old, oldt;
> +
> +		oldt = uatomic_read((unsigned int *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned int *)addr,
> +                                               old, old | val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#if (BITS_PER_LONG == 64)
> +	case 8:
> +	{
> +		unsigned long old, oldt;
> +
> +		oldt = uatomic_read((unsigned long *)addr);
> +		do {
> +			old = oldt;
> +			oldt = uatomic_cmpxchg((unsigned long *)addr,
> +                                               old, old | val);
> +		} while (oldt != old);
> +
> +		return old;
> +	}
> +#endif
> +	}
> +	_uatomic_link_error();
> +	return 0;
> +}
> +
> +#define uatomic_or(addr, v)					\
> +	((__typeof__(*(addr))) _uatomic_or((addr),		\
> +					   (unsigned long)(v),	\
> +					   sizeof(*(addr))))
> +#endif /* #ifndef uatomic_or */
> +
>  #ifndef uatomic_add_return
>  /* uatomic_add_return */
>  
> -- 
> 1.7.3.2
> 
> 
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> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com