From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55954) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cKdWY-00079V-Oq for qemu-devel@nongnu.org; Fri, 23 Dec 2016 23:01:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cKdWY-00066p-25 for qemu-devel@nongnu.org; Fri, 23 Dec 2016 23:01:34 -0500 Received: from mail-pg0-x244.google.com ([2607:f8b0:400e:c05::244]:34863) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cKdWX-00066U-Tl for qemu-devel@nongnu.org; Fri, 23 Dec 2016 23:01:34 -0500 Received: by mail-pg0-x244.google.com with SMTP id i5so2481104pgh.2 for ; Fri, 23 Dec 2016 20:01:33 -0800 (PST) Received: from bigtime.domain ([2602:47:d954:1500:5e51:4fff:fe40:9c64]) by smtp.gmail.com with ESMTPSA id n25sm65339316pfi.33.2016.12.23.20.01.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Dec 2016 20:01:32 -0800 (PST) Sender: Richard Henderson From: Richard Henderson Date: Fri, 23 Dec 2016 20:00:38 -0800 Message-Id: <20161224040042.12654-62-rth@twiddle.net> In-Reply-To: <20161224040042.12654-1-rth@twiddle.net> References: <20161224040042.12654-1-rth@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH 61/65] qemu/host-utils.h: Reduce the operation count in the fallback ctpop List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- include/qemu/host-utils.h | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 46187bb..96288d0 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -327,7 +327,7 @@ static inline int ctpop8(uint8_t val) #else val = (val & 0x55) + ((val >> 1) & 0x55); val = (val & 0x33) + ((val >> 2) & 0x33); - val = (val & 0x0f) + ((val >> 4) & 0x0f); + val = (val + (val >> 4)) & 0x0f; return val; #endif @@ -344,8 +344,8 @@ static inline int ctpop16(uint16_t val) #else val = (val & 0x5555) + ((val >> 1) & 0x5555); val = (val & 0x3333) + ((val >> 2) & 0x3333); - val = (val & 0x0f0f) + ((val >> 4) & 0x0f0f); - val = (val & 0x00ff) + ((val >> 8) & 0x00ff); + val = (val + (val >> 4)) & 0x0f0f; + val = (val + (val >> 8)) & 0x00ff; return val; #endif @@ -360,11 +360,10 @@ static inline int ctpop32(uint32_t val) #if QEMU_GNUC_PREREQ(3, 4) return __builtin_popcount(val); #else - val = (val & 0x55555555) + ((val >> 1) & 0x55555555); - val = (val & 0x33333333) + ((val >> 2) & 0x33333333); - val = (val & 0x0f0f0f0f) + ((val >> 4) & 0x0f0f0f0f); - val = (val & 0x00ff00ff) + ((val >> 8) & 0x00ff00ff); - val = (val & 0x0000ffff) + ((val >> 16) & 0x0000ffff); + val = (val & 0x55555555) + ((val >> 1) & 0x55555555); + val = (val & 0x33333333) + ((val >> 2) & 0x33333333); + val = (val + (val >> 4)) & 0x0f0f0f0f; + val = (val * 0x01010101) >> 24; return val; #endif @@ -379,12 +378,10 @@ static inline int ctpop64(uint64_t val) #if QEMU_GNUC_PREREQ(3, 4) return __builtin_popcountll(val); #else - val = (val & 0x5555555555555555ULL) + ((val >> 1) & 0x5555555555555555ULL); - val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL); - val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >> 4) & 0x0f0f0f0f0f0f0f0fULL); - val = (val & 0x00ff00ff00ff00ffULL) + ((val >> 8) & 0x00ff00ff00ff00ffULL); - val = (val & 0x0000ffff0000ffffULL) + ((val >> 16) & 0x0000ffff0000ffffULL); - val = (val & 0x00000000ffffffffULL) + ((val >> 32) & 0x00000000ffffffffULL); + val = (val & 0x5555555555555555ULL) + ((val >> 1) & 0x5555555555555555ULL); + val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL); + val = (val + (val >> 4)) & 0x0f0f0f0f0f0f0f0fULL; + val = (val * 0x0101010101010101ULL) >> 56; return val; #endif -- 2.9.3