From patchwork Tue Jun 28 14:50:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 641584 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3rf84b0nggz9sp7 for ; Wed, 29 Jun 2016 00:55:43 +1000 (AEST) Received: from localhost ([::1]:37340 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHuQO-0002aR-P7 for incoming@patchwork.ozlabs.org; Tue, 28 Jun 2016 10:55:40 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37791) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHuLu-0006Yq-EH for qemu-devel@nongnu.org; Tue, 28 Jun 2016 10:51:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bHuLs-0005c8-76 for qemu-devel@nongnu.org; Tue, 28 Jun 2016 10:51:01 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:58021) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHuLs-0005b0-0k; Tue, 28 Jun 2016 10:51:00 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1bHuLm-00066A-Qw; Tue, 28 Jun 2016 15:50:54 +0100 From: Peter Maydell To: qemu-devel@nongnu.org, qemu-trivial@nongnu.org Date: Tue, 28 Jun 2016 15:50:51 +0100 Message-Id: <1467125451-16700-7-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1467125451-16700-1-git-send-email-peter.maydell@linaro.org> References: <1467125451-16700-1-git-send-email-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH 6/6] bswap.h: Document cpu_to_* and *_to_cpu conversion functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: patches@linaro.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Add a documentation comment describing the functions for converting between the cpu and little or bigendian formats. Signed-off-by: Peter Maydell Reviewed-by: Eric Blake --- include/qemu/bswap.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h index a17d9aa..be3233a 100644 --- a/include/qemu/bswap.h +++ b/include/qemu/bswap.h @@ -80,6 +80,64 @@ static inline void bswap64s(uint64_t *s) #define be_bswaps(p, size) do { *p = glue(bswap, size)(*p); } while(0) #endif +/** + * Endianness conversion functions between host cpu and specified endianness. + * (We list the complete set of prototypes produced by the macros below + * to assist people who search the headers to find their definitions.) + * + * uint16_t le16_to_cpu(uint16_t v); + * uint32_t le32_to_cpu(uint32_t v); + * uint64_t le64_to_cpu(uint64_t v); + * uint16_t be16_to_cpu(uint16_t v); + * uint32_t be32_to_cpu(uint32_t v); + * uint64_t be64_to_cpu(uint64_t v); + * + * Convert the value @v from the specified format to the native + * endianness of the host CPU by byteswapping if necessary, and + * return the converted value. + * + * uint16_t cpu_to_le16(uint16_t v); + * uint32_t cpu_to_le32(uint32_t v); + * uint64_t cpu_to_le64(uint64_t v); + * uint16_t cpu_to_be16(uint16_t v); + * uint32_t cpu_to_be32(uint32_t v); + * uint64_t cpu_to_be64(uint64_t v); + * + * Convert the value @v from the native endianness of the host CPU to + * the specified format by byteswapping if necessary, and return + * the converted value. + * + * uint16_t le16_to_cpus(uint16_t *v); + * uint32_t le32_to_cpus(uint32_t *v); + * uint64_t le64_to_cpus(uint64_t *v); + * uint16_t be16_to_cpus(uint16_t *v); + * uint32_t be32_to_cpus(uint32_t *v); + * uint64_t be64_to_cpus(uint64_t *v); + * + * Do an in-place conversion of the value pointed to by @v from the + * specified format to the native endianness of the host CPU. + * + * uint16_t cpu_to_le16s(uint16_t *v); + * uint32_t cpu_to_le32s(uint32_t *v); + * uint64_t cpu_to_le64s(uint64_t *v); + * uint16_t cpu_to_be16s(uint16_t *v); + * uint32_t cpu_to_be32s(uint32_t *v); + * uint64_t cpu_to_be64s(uint64_t *v); + * + * Do an in-place conversion of the value pointed to by @v from the + * native endianness of the host CPU to the specified format. + * + * Both X_to_cpu() and cpu_to_X() perform the same operation; you + * should use whichever one is better documenting of the function your + * code is performing. + * + * Do not use these functions for conversion of values which are in guest + * memory, since the data may not be sufficiently aligned for the host CPU's + * load and store instructions. Instead you should use the ld*_p() and + * st*_p() functions, which perform loads and stores of data of any + * required size and endianness and handle possible misalignment. + */ + #define CPU_CONVERT(endian, size, type)\ static inline type endian ## size ## _to_cpu(type v)\ {\