From bfc5e1ebbf2b9cebedddc653f502d1dfc31fda89 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 25 Feb 2021 13:48:52 +0100 Subject: [PATCH] macro: add hweight*() helpers Signed-off-by: Christian Brauner --- src/lxc/macro.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/src/lxc/macro.h b/src/lxc/macro.h index 421e63e9f..8d9b1174c 100644 --- a/src/lxc/macro.h +++ b/src/lxc/macro.h @@ -680,4 +680,29 @@ enum { _min1 < _min2 ? _min1 : _min2; \ }) +#define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) + +/* + * Compile time versions of __arch_hweightN() + */ +#define __const_hweight8(w) \ + ((unsigned int) \ + ((!!((w) & (1ULL << 0))) + \ + (!!((w) & (1ULL << 1))) + \ + (!!((w) & (1ULL << 2))) + \ + (!!((w) & (1ULL << 3))) + \ + (!!((w) & (1ULL << 4))) + \ + (!!((w) & (1ULL << 5))) + \ + (!!((w) & (1ULL << 6))) + \ + (!!((w) & (1ULL << 7))))) + +#define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 )) +#define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16)) +#define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32)) + +#define hweight8(w) __const_hweight8(w) +#define hweight16(w) __const_hweight16(w) +#define hweight32(w) __const_hweight32(w) +#define hweight64(w) __const_hweight64(w) + #endif /* __LXC_MACRO_H */ -- 2.47.3