From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43241) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbcTg-0005Qi-EY for qemu-devel@nongnu.org; Mon, 14 Sep 2015 18:44:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZbcTf-0003AI-DP for qemu-devel@nongnu.org; Mon, 14 Sep 2015 18:44:00 -0400 Received: from mail-pa0-x229.google.com ([2607:f8b0:400e:c03::229]:36496) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbcTf-0003A2-69 for qemu-devel@nongnu.org; Mon, 14 Sep 2015 18:43:59 -0400 Received: by padhk3 with SMTP id hk3so155643098pad.3 for ; Mon, 14 Sep 2015 15:43:58 -0700 (PDT) Sender: Richard Henderson From: Richard Henderson Date: Mon, 14 Sep 2015 15:43:23 -0700 Message-Id: <1442270622-8955-17-git-send-email-rth@twiddle.net> In-Reply-To: <1442270622-8955-1-git-send-email-rth@twiddle.net> References: <1442270622-8955-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH v16 16/35] host-utils: Add revbit functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org Signed-off-by: Richard Henderson --- include/qemu/host-utils.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 7d36ebf..3ef97d5 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -26,6 +26,7 @@ #define HOST_UTILS_H 1 #include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */ +#include "qemu/bswap.h" #include #include @@ -391,6 +392,80 @@ static inline int ctpop64(uint64_t val) #endif } +/** + * revbit8 - reverse the bits in an 8-bit value. + * @x: The value to modify. + */ +static inline uint8_t revbit8(uint8_t x) +{ + /* Assign the correct nibble position. */ + x = ((x & 0xf0) >> 4) + | ((x & 0x0f) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x88) >> 3) + | ((x & 0x44) >> 1) + | ((x & 0x22) << 1) + | ((x & 0x11) << 3); + return x; +} + +/** + * revbit16 - reverse the bits in a 16-bit value. + * @x: The value to modify. + */ +static inline uint16_t revbit16(uint16_t x) +{ + /* Assign the correct byte position. */ + x = bswap16(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0) >> 4) + | ((x & 0x0f0f) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x8888) >> 3) + | ((x & 0x4444) >> 1) + | ((x & 0x2222) << 1) + | ((x & 0x1111) << 3); + return x; +} + +/** + * revbit32 - reverse the bits in a 32-bit value. + * @x: The value to modify. + */ +static inline uint32_t revbit32(uint32_t x) +{ + /* Assign the correct byte position. */ + x = bswap32(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0f0f0u) >> 4) + | ((x & 0x0f0f0f0fu) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x88888888u) >> 3) + | ((x & 0x44444444u) >> 1) + | ((x & 0x22222222u) << 1) + | ((x & 0x11111111u) << 3); + return x; +} + +/** + * revbit64 - reverse the bits in a 64-bit value. + * @x: The value to modify. + */ +static inline uint64_t revbit64(uint64_t x) +{ + /* Assign the correct byte position. */ + x = bswap64(x); + /* Assign the correct nibble position. */ + x = ((x & 0xf0f0f0f0f0f0f0f0ull) >> 4) + | ((x & 0x0f0f0f0f0f0f0f0full) << 4); + /* Assign the correct bit position. */ + x = ((x & 0x8888888888888888ull) >> 3) + | ((x & 0x4444444444444444ull) >> 1) + | ((x & 0x2222222222222222ull) << 1) + | ((x & 0x1111111111111111ull) << 3); + return x; +} + /* Host type specific sizes of these routines. */ #if ULONG_MAX == UINT32_MAX @@ -399,12 +474,14 @@ static inline int ctpop64(uint64_t val) # define clol clo32 # define ctol cto32 # define ctpopl ctpop32 +# define revbitl revbit32 #elif ULONG_MAX == UINT64_MAX # define clzl clz64 # define ctzl ctz64 # define clol clo64 # define ctol cto64 # define ctpopl ctpop64 +# define revbitl revbit64 #else # error Unknown sizeof long #endif -- 2.4.3