| 1 | #ifndef _LINUX_BYTEORDER_GENERIC_H |
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| 2 | #define _LINUX_BYTEORDER_GENERIC_H |
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| 3 | |
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| 4 | /* |
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| 5 | * linux/byteorder_generic.h |
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| 6 | * Generic Byte-reordering support |
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| 7 | * |
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| 8 | * Francois-Rene Rideau <fare@tunes.org> 19970707 |
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| 9 | * gathered all the good ideas from all asm-foo/byteorder.h into one file, |
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| 10 | * cleaned them up. |
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| 11 | * I hope it is compliant with non-GCC compilers. |
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| 12 | * I decided to put __BYTEORDER_HAS_U64__ in byteorder.h, |
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| 13 | * because I wasn't sure it would be ok to put it in types.h |
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| 14 | * Upgraded it to 2.1.43 |
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| 15 | * Francois-Rene Rideau <fare@tunes.org> 19971012 |
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| 16 | * Upgraded it to 2.1.57 |
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| 17 | * to please Linus T., replaced huge #ifdef's between little/big endian |
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| 18 | * by nestedly #include'd files. |
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| 19 | * Francois-Rene Rideau <fare@tunes.org> 19971205 |
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| 20 | * Made it to 2.1.71; now a facelift: |
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| 21 | * Put files under include/linux/byteorder/ |
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| 22 | * Split swab from generic support. |
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| 23 | * |
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| 24 | * TODO: |
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| 25 | * = Regular kernel maintainers could also replace all these manual |
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| 26 | * byteswap macros that remain, disseminated among drivers, |
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| 27 | * after some grep or the sources... |
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| 28 | * = Linus might want to rename all these macros and files to fit his taste, |
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| 29 | * to fit his personal naming scheme. |
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| 30 | * = it seems that a few drivers would also appreciate |
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| 31 | * nybble swapping support... |
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| 32 | * = every architecture could add their byteswap macro in asm/byteorder.h |
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| 33 | * see how some architectures already do (i386, alpha, ppc, etc) |
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| 34 | * = cpu_to_beXX and beXX_to_cpu might some day need to be well |
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| 35 | * distinguished throughout the kernel. This is not the case currently, |
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| 36 | * since little endian, big endian, and pdp endian machines needn't it. |
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| 37 | * But this might be the case for, say, a port of Linux to 20/21 bit |
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| 38 | * architectures (and F21 Linux addict around?). |
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| 39 | */ |
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| 40 | |
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| 41 | /* |
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| 42 | * The following macros are to be defined by <asm/byteorder.h>: |
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| 43 | * |
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| 44 | * Conversion of long and short int between network and host format |
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| 45 | * ntohl(__u32 x) |
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| 46 | * ntohs(__u16 x) |
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| 47 | * htonl(__u32 x) |
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| 48 | * htons(__u16 x) |
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| 49 | * It seems that some programs (which? where? or perhaps a standard? POSIX?) |
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| 50 | * might like the above to be functions, not macros (why?). |
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| 51 | * if that's true, then detect them, and take measures. |
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| 52 | * Anyway, the measure is: define only ___ntohl as a macro instead, |
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| 53 | * and in a separate file, have |
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| 54 | * unsigned long inline ntohl(x){return ___ntohl(x);} |
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| 55 | * |
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| 56 | * The same for constant arguments |
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| 57 | * __constant_ntohl(__u32 x) |
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| 58 | * __constant_ntohs(__u16 x) |
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| 59 | * __constant_htonl(__u32 x) |
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| 60 | * __constant_htons(__u16 x) |
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| 61 | * |
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| 62 | * Conversion of XX-bit integers (16- 32- or 64-) |
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| 63 | * between native CPU format and little/big endian format |
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| 64 | * 64-bit stuff only defined for proper architectures |
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| 65 | * cpu_to_[bl]eXX(__uXX x) |
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| 66 | * [bl]eXX_to_cpu(__uXX x) |
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| 67 | * |
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| 68 | * The same, but takes a pointer to the value to convert |
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| 69 | * cpu_to_[bl]eXXp(__uXX x) |
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| 70 | * [bl]eXX_to_cpup(__uXX x) |
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| 71 | * |
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| 72 | * The same, but change in situ |
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| 73 | * cpu_to_[bl]eXXs(__uXX x) |
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| 74 | * [bl]eXX_to_cpus(__uXX x) |
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| 75 | * |
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| 76 | * See asm-foo/byteorder.h for examples of how to provide |
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| 77 | * architecture-optimized versions |
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| 78 | * |
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| 79 | */ |
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| 80 | |
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| 81 | #endif /* _LINUX_BYTEORDER_GENERIC_H */ |
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