From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43045) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UD9fp-0001la-LA for qemu-devel@nongnu.org; Wed, 06 Mar 2013 03:26:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UD9fo-0000RT-Ev for qemu-devel@nongnu.org; Wed, 06 Mar 2013 03:26:05 -0500 Received: from mail-gg0-x230.google.com ([2607:f8b0:4002:c02::230]:59288) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UD9fo-0000RN-9V for qemu-devel@nongnu.org; Wed, 06 Mar 2013 03:26:04 -0500 Received: by mail-gg0-f176.google.com with SMTP id q6so1138921ggc.7 for ; Wed, 06 Mar 2013 00:26:03 -0800 (PST) Sender: Paolo Bonzini Message-ID: <5136FD98.3030901@redhat.com> Date: Wed, 06 Mar 2013 09:26:00 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1362554857-3896-1-git-send-email-dantesu@gmail.com> <1362554857-3896-18-git-send-email-dantesu@gmail.com> In-Reply-To: <1362554857-3896-18-git-send-email-dantesu@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 17/24] qemu/bitops.h: add the bit ordering reversal functions stolen from linux List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kuo-Jung Su Cc: Peter Maydell , i.mitsyanko@samsung.com, qemu-devel@nongnu.org, Blue Swirl , Paul Brook , Andreas , fred.konrad@greensocs.com Il 06/03/2013 08:27, Kuo-Jung Su ha scritto: > Signed-off-by: Kuo-Jung Su > --- > include/qemu/bitops.h | 63 ++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 62 insertions(+), 1 deletion(-) > > diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h > index affcc96..920d028 100644 > --- a/include/qemu/bitops.h > +++ b/include/qemu/bitops.h > @@ -3,7 +3,8 @@ > * > * Copyright (C) 2010 Corentin Chary > * > - * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h > + * Mostly inspired by (stolen from) linux/bitmap.h, linux/bitops.h > + * and linux/bitrev.h > * > * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. > * See the COPYING.LIB file in the top-level directory. > @@ -273,4 +274,64 @@ static inline uint64_t deposit64(uint64_t value, int start, int length, > return (value & ~mask) | ((fieldval << start) & mask); > } > > +/** > + * bitrev8: > + * @value: the value to reverse bit ordering from > + * > + * Reverse the 8 bit input @value > + * > + * Returns: the input @value with reversed bit ordering > + */ > +static inline uint8_t bitrev8(uint8_t value) > +{ > + int i; > + uint8_t ret = 0; > + for (i = 0; i < 8; ++i) { > + if (value & BIT(i)) { > + ret |= BIT(7 - i); > + } > + } Please use instead value = ((value & 0xAA) >> 1) | ((value & 0x55) << 1); value = ((value & 0xCC) >> 2) | ((value & 0x33) << 2); value = ((value & 0xF0) >> 4) | ((value & 0x0F) << 4); return value; Paolo > + return ret; > +} > + > +/** > + * bitrev16: > + * @value: the value to reverse bit ordering from > + * > + * Reverse the 16 bit input @value > + * > + * Returns: the input @value with reversed bit ordering > + */ > +static inline uint16_t bitrev16(uint16_t value) > +{ > + return (bitrev8(value & 0xff) << 8) | bitrev8(value >> 8); > +} > + > +/** > + * bitrev32: > + * @value: the value to reverse bit ordering from > + * > + * Reverse the 32 bit input @value > + * > + * Returns: the input @value with reversed bit ordering > + */ > +static inline uint32_t bitrev32(uint32_t value) > +{ > + return (bitrev16(value & 0xffff) << 16) | bitrev16(value >> 16); > +} > + > +/** > + * bitrev64: > + * @value: the value to reverse bit ordering from > + * > + * Reverse the 64 bit input @value > + * > + * Returns: the input @value with reversed bit ordering > + */ > +static inline uint64_t bitrev64(uint64_t value) > +{ > + return ((uint64_t)bitrev32(value & 0xffffffffULL) << 32) > + | (uint64_t)bitrev32(value >> 32); > +} > + > #endif >