Am 2016-05-11 um 10:47 schrieb zengzhaoxiu@xxxxxxx: > From: Zhaoxiu Zeng <zhaoxiu.zeng@xxxxxxxxx> > > Add generic parity functions, adapted from > "https://graphics.stanford.edu/~seander/bithacks.html#ParityParallel";. > > The function parityN returns whether an odd or even number of bits are on > in a N-bit word. > > Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@xxxxxxxxx> > --- This won't be up to me, but I'd appreciate to see all 31 patches together without having to look for them; I guess I'm not alone. thanks martin > include/asm-generic/bitops.h | 1 + > include/asm-generic/bitops/arch_parity.h | 39 +++++++++++++++++++++++++++++++ > include/asm-generic/bitops/const_parity.h | 36 ++++++++++++++++++++++++++++ > include/asm-generic/bitops/parity.h | 7 ++++++ > include/asm-generic/bitops/popc-parity.h | 32 +++++++++++++++++++++++++ > include/linux/bitops.h | 10 ++++++++ > 6 files changed, 125 insertions(+) > create mode 100644 include/asm-generic/bitops/arch_parity.h > create mode 100644 include/asm-generic/bitops/const_parity.h > create mode 100644 include/asm-generic/bitops/parity.h > create mode 100644 include/asm-generic/bitops/popc-parity.h > > diff --git a/include/asm-generic/bitops.h b/include/asm-generic/bitops.h > index dcdcacf..d85722f 100644 > --- a/include/asm-generic/bitops.h > +++ b/include/asm-generic/bitops.h > @@ -27,6 +27,7 @@ > #include <asm-generic/bitops/sched.h> > #include <asm-generic/bitops/ffs.h> > #include <asm-generic/bitops/hweight.h> > +#include <asm-generic/bitops/parity.h> > #include <asm-generic/bitops/lock.h> > > #include <asm-generic/bitops/atomic.h> > diff --git a/include/asm-generic/bitops/arch_parity.h b/include/asm-generic/bitops/arch_parity.h > new file mode 100644 > index 0000000..813e152 > --- /dev/null > +++ b/include/asm-generic/bitops/arch_parity.h > @@ -0,0 +1,39 @@ > +#ifndef _ASM_GENERIC_BITOPS_ARCH_PARITY_H_ > +#define _ASM_GENERIC_BITOPS_ARCH_PARITY_H_ > + > +#include <asm/types.h> > + > +/* > + * Refrence to 'https://graphics.stanford.edu/~seander/bithacks.html#ParityParallel'. > + */ > + > +static inline unsigned int __arch_parity4(unsigned int w) > +{ > + w &= 0xf; > + return ((PARITY_MAGIC) >> w) & 1; > +} > + > +static inline unsigned int __arch_parity8(unsigned int w) > +{ > + w ^= w >> 4; > + return __arch_parity4(w); > +} > + > +static inline unsigned int __arch_parity16(unsigned int w) > +{ > + w ^= w >> 8; > + return __arch_parity8(w); > +} > + > +static inline unsigned int __arch_parity32(unsigned int w) > +{ > + w ^= w >> 16; > + return __arch_parity16(w); > +} > + > +static inline unsigned int __arch_parity64(__u64 w) > +{ > + return __arch_parity32((unsigned int)(w >> 32) ^ (unsigned int)w); > +} > + > +#endif /* _ASM_GENERIC_BITOPS_ARCH_PARITY_H_ */ > diff --git a/include/asm-generic/bitops/const_parity.h b/include/asm-generic/bitops/const_parity.h > new file mode 100644 > index 0000000..3970546 > --- /dev/null > +++ b/include/asm-generic/bitops/const_parity.h > @@ -0,0 +1,36 @@ > +#ifndef _ASM_GENERIC_BITOPS_CONST_PARITY_H_ > +#define _ASM_GENERIC_BITOPS_CONST_PARITY_H_ > + > +/* > + * Compile time versions of __arch_parityN() > + */ > +#define __const_parity4(w) (((PARITY_MAGIC) >> ((w) & 0xf)) & 1) > +#define __const_parity8(w) (__const_parity4((w) ^ ((w) >> 4))) > +#define __const_parity16(w) (__const_parity8((w) ^ ((w) >> 8))) > +#define __const_parity32(w) (__const_parity16((w) ^ ((w) >> 16))) > +#define __const_parity64(w) (__const_parity32((w) ^ ((w) >> 32))) > + > +/* > + * Generic interface. > + */ > +#define parity4(w) (__builtin_constant_p(w) ? __const_parity4(w) : __arch_parity4(w)) > +#define parity8(w) (__builtin_constant_p(w) ? __const_parity8(w) : __arch_parity8(w)) > +#define parity16(w) (__builtin_constant_p(w) ? __const_parity16(w) : __arch_parity16(w)) > +#define parity32(w) (__builtin_constant_p(w) ? __const_parity32(w) : __arch_parity32(w)) > +#define parity64(w) (__builtin_constant_p(w) ? __const_parity64(w) : __arch_parity64(w)) > + > +/* > + * Interface for known constant arguments > + */ > +#define PARITY4(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_parity4(w)) > +#define PARITY8(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_parity8(w)) > +#define PARITY16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_parity16(w)) > +#define PARITY32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_parity32(w)) > +#define PARITY64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_parity64(w)) > + > +/* > + * Type invariant interface to the compile time constant parity functions. > + */ > +#define PARITY(w) PARITY64((u64)(w)) > + > +#endif /* _ASM_GENERIC_BITOPS_CONST_PARITY_H_ */ > diff --git a/include/asm-generic/bitops/parity.h b/include/asm-generic/bitops/parity.h > new file mode 100644 > index 0000000..a91dce7 > --- /dev/null > +++ b/include/asm-generic/bitops/parity.h > @@ -0,0 +1,7 @@ > +#ifndef _ASM_GENERIC_BITOPS_PARITY_H_ > +#define _ASM_GENERIC_BITOPS_PARITY_H_ > + > +#include <asm-generic/bitops/arch_parity.h> > +#include <asm-generic/bitops/const_parity.h> > + > +#endif /* _ASM_GENERIC_BITOPS_PARITY_H_ */ > diff --git a/include/asm-generic/bitops/popc-parity.h b/include/asm-generic/bitops/popc-parity.h > new file mode 100644 > index 0000000..bf05999 > --- /dev/null > +++ b/include/asm-generic/bitops/popc-parity.h > @@ -0,0 +1,32 @@ > +#ifndef _ASM_GENERIC_BITOPS_POPC_PARITY_H_ > +#define _ASM_GENERIC_BITOPS_POPC_PARITY_H_ > + > +#include <asm/types.h> > + > +static inline unsigned int __arch_parity32(unsigned int w) > +{ > + return __builtin_popcount(w) & 1; > +} > + > +static inline unsigned int __arch_parity16(unsigned int w) > +{ > + return __arch_parity32(w & 0xffff); > +} > + > +static inline unsigned int __arch_parity8(unsigned int w) > +{ > + return __arch_parity32(w & 0xff); > +} > + > +static inline unsigned int __arch_parity4(unsigned int w) > +{ > + return __arch_parity32(w & 0xf); > +} > + > +static inline unsigned int __arch_parity64(__u64 w) > +{ > + return (unsigned int)__builtin_popcountll(w) & 1; > +} > + > +#endif > + > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > index defeaac..c3ea19e 100644 > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -30,6 +30,11 @@ extern unsigned int __sw_hweight32(unsigned int w); > extern unsigned long __sw_hweight64(__u64 w); > > /* > + * a miniature 16-bit parity-table of 4-bits number > + */ > +#define PARITY_MAGIC 0x6996 > + > +/* > * Include this here because some architectures need generic_ffs/fls in > * scope > */ > @@ -80,6 +85,11 @@ static __always_inline unsigned long hweight_long(unsigned long w) > return sizeof(w) == 4 ? hweight32(w) : hweight64(w); > } > > +static __always_inline unsigned int parity_long(unsigned long w) > +{ > + return sizeof(w) == 4 ? parity32(w) : parity64(w); > +} > + > /** > * rol64 - rotate a 64-bit value left > * @word: value to rotate > -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
