Date: Fri, 19 Dec 2025 21:17:25 +0000 From: Bjoern A. Zeeb <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 27aa23cee810 - main - sys/bitcount.h: add __const_bitcount<n> Message-ID: <6945c0e5.3cec0.254dfc3e@gitrepo.freebsd.org>
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The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=27aa23cee81088b0ffa974eec9f03c654c36438e commit 27aa23cee81088b0ffa974eec9f03c654c36438e Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2025-09-15 23:54:57 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2025-12-19 21:16:20 +0000 sys/bitcount.h: add __const_bitcount<n> Add a version of __const_bitcount<n> which can be used to get the numbers at compile-time when __builtin_popcountg() is not available (see sys/compat/linuxkpi/common/include/linux/bitops.h for LLVM before 19 and gcc before 14). Obtained from: https://reviews.freebsd.org/D50995#1174884 by obiwac Sponsored by: The FreeBSD Foundation Reviewed by: brooks, emaste Differential Revision: https://reviews.freebsd.org/D54301 --- sys/sys/bitcount.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/sys/sys/bitcount.h b/sys/sys/bitcount.h index 171425032680..919dc4be06fc 100644 --- a/sys/sys/bitcount.h +++ b/sys/sys/bitcount.h @@ -39,6 +39,28 @@ #include <sys/_types.h> +#define __const_bitcount8(x) ( \ + !!((x) & (1 << 0)) + \ + !!((x) & (1 << 1)) + \ + !!((x) & (1 << 2)) + \ + !!((x) & (1 << 3)) + \ + !!((x) & (1 << 4)) + \ + !!((x) & (1 << 5)) + \ + !!((x) & (1 << 6)) + \ + !!((x) & (1 << 7))) + +#define __const_bitcount16(x) ( \ + __const_bitcount8(x) + \ + __const_bitcount8((x) >> 8)) + +#define __const_bitcount32(x) ( \ + __const_bitcount16(x) + \ + __const_bitcount16((x) >> 16)) + +#define __const_bitcount64(x) ( \ + __const_bitcount32(x) + \ + __const_bitcount32((x) >> 32)) + #ifdef __POPCNT__ #define __bitcount64(x) __builtin_popcountll((__uint64_t)(x)) #define __bitcount32(x) __builtin_popcount((__uint32_t)(x))help
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