From: Thomas Monjalon <thomas.monjalon@6wind.com> To: "Qiu, Michael" <michael.qiu@intel.com> Cc: dev@dpdk.org, Chao Zhu <chaozhu@linux.vnet.ibm.com> Subject: Re: [dpdk-dev] [PATCH 1/2] eal: detect endianness Date: Thu, 04 Dec 2014 10:00:09 +0100 Message-ID: <3580620.HEA1jLh5UM@xps13> (raw) In-Reply-To: <533710CFB86FA344BFBF2D6802E60286C9C86D@SHSMSX101.ccr.corp.intel.com> 2014-12-04 02:28, Qiu, Michael: > On 12/4/2014 5:26 AM, Thomas Monjalon wrote: > > There is no standard to check endianness. > > So we need to try different checks. > > Previous trials were done in testpmd (see commits > > 51f694dd40f56 and 64741f237cf29) without full success. > > This one is not guaranteed to work everywhere so it could > > evolve when exceptions are found. [...] > > #include <stdint.h> > > +#ifdef RTE_EXEC_ENV_BSDAPP > > +#include <sys/endian.h> > > +#else > > +#include <endian.h> > > +#endif > > + > > +/* > > + * Compile-time endianness detection > > + */ > > +#define RTE_BIG_ENDIAN 1 > > +#define RTE_LITTLE_ENDIAN 2 > > +#if defined __BYTE_ORDER > > +#if __BYTE_ORDER == __BIG_ENDIAN > > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > > +#elif __BYTE_ORDER == __LITTLE_ENDIAN > > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > > +#endif /* __BYTE_ORDER */ > > +#elif defined __BYTE_ORDER__ > > +#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ > > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > > +#elif __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ > > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > > +#endif /* __BYTE_ORDER__ */ > > +#elif defined __BIG_ENDIAN__ > > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > > +#elif defined __LITTLE_ENDIAN__ > > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > > +#endif > > What do you think about : > > +/* > + * Compile-time endianness detection > + */ > +#define RTE_BIG_ENDIAN 1 > +#define RTE_LITTLE_ENDIAN 2 > +if defined __BYTE_ORDER__ /* Prefer gcc build-in macros */ > +#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > +#elif __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > +#endif /* __BYTE_ORDER__ */ > +#else > +#if defined RTE_EXEC_ENV_BSDAPP > +#include <sys/endian.h> > +#else > +#include <endian.h> > +#endif > +#if defined __BYTE_ORDER > +#if __BYTE_ORDER == __BIG_ENDIAN > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > +#elif __BYTE_ORDER == __LITTLE_ENDIAN > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > +#endif /* __BYTE_ORDER */ > +#elif defined __BIG_ENDIAN__ > +#define RTE_BYTE_ORDER RTE_BIG_ENDIAN > +#elif defined __LITTLE_ENDIAN__ > +#define RTE_BYTE_ORDER RTE_LITTLE_ENDIAN > +#endif > +#endif Please, could you give more explanations about your proposal? Why not always try to include endian.h? Why giving high priority to __BYTE_ORDER__? -- Thomas
next prev parent reply other threads:[~2014-12-04 9:00 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <1417606044-3432-1-git-send-email-michael.qiu@intel.com> [not found] ` <1417606099-3489-1-git-send-email-michael.qiu@intel.com> 2014-12-03 11:42 ` [dpdk-dev] [PATCH] test-pmd: Fix pointer aliasing error Bruce Richardson 2014-12-03 13:59 ` Qiu, Michael 2014-12-03 14:51 ` Bruce Richardson 2014-12-03 15:19 ` Qiu, Michael 2014-12-03 15:36 ` Bruce Richardson 2014-12-04 2:38 ` Qiu, Michael 2014-12-04 3:28 ` [dpdk-dev] [PATCH v2] " Michael Qiu 2014-12-04 4:16 ` [dpdk-dev] [PATCH v3] " Michael Qiu 2014-12-05 5:34 ` Qiu, Michael 2014-12-05 9:24 ` Thomas Monjalon 2014-12-08 1:28 ` Qiu, Michael 2014-12-08 1:30 ` Qiu, Michael 2014-12-10 3:44 ` Qiu, Michael 2014-12-11 0:54 ` Thomas Monjalon 2014-12-11 17:51 ` r k 2014-12-12 6:49 ` Qiu, Michael 2014-12-04 12:54 ` [dpdk-dev] [PATCH v2] " Ananyev, Konstantin 2014-12-03 15:24 ` [dpdk-dev] [PATCH] " Olivier MATZ 2014-12-03 16:03 ` Dayu Qiu 2014-12-03 15:57 ` Dayu Qiu 2014-12-03 16:26 ` [dpdk-dev] [PATCH] test-pmd: Fix "__BYTE_ORDER__" not defined error Qiu, Michael 2014-12-03 19:59 ` Thomas Monjalon 2014-12-03 20:47 ` [dpdk-dev] [PATCH 0/2] fix endianness in EAL Thomas Monjalon 2014-12-03 20:47 ` [dpdk-dev] [PATCH 1/2] eal: detect endianness Thomas Monjalon 2014-12-04 2:28 ` Qiu, Michael 2014-12-04 9:00 ` Thomas Monjalon [this message] 2014-12-04 10:28 ` Qiu, Michael 2014-12-04 12:19 ` Thomas Monjalon 2014-12-04 12:50 ` Qiu, Michael 2014-12-03 20:47 ` [dpdk-dev] [PATCH 2/2] app/testpmd: fix endianness detection Thomas Monjalon 2014-12-04 9:28 ` [dpdk-dev] [PATCH 0/2] fix endianness in EAL Chao Zhu 2014-12-05 16:01 ` Thomas Monjalon
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