1 #ifndef _LINUX_BYTEORDER_GENERIC_H
2 #define _LINUX_BYTEORDER_GENERIC_H
3 
4 /*
5  * linux/byteorder_generic.h
6  * Generic Byte-reordering support
7  *
8  * Francois-Rene Rideau <fare@tunes.org> 19970707
9  *    gathered all the good ideas from all asm-foo/byteorder.h into one file,
10  *    cleaned them up.
11  *    I hope it is compliant with non-GCC compilers.
12  *    I decided to put __BYTEORDER_HAS_U64__ in byteorder.h,
13  *    because I wasn't sure it would be ok to put it in types.h
14  *    Upgraded it to 2.1.43
15  * Francois-Rene Rideau <fare@tunes.org> 19971012
16  *    Upgraded it to 2.1.57
17  *    to please Linus T., replaced huge #ifdef's between little/big endian
18  *    by nestedly #include'd files.
19  * Francois-Rene Rideau <fare@tunes.org> 19971205
20  *    Made it to 2.1.71; now a facelift:
21  *    Put files under include/linux/byteorder/
22  *    Split swab from generic support.
23  *
24  * TODO:
25  *   = Regular kernel maintainers could also replace all these manual
26  *    byteswap macros that remain, disseminated among drivers,
27  *    after some grep or the sources...
28  *   = Linus might want to rename all these macros and files to fit his taste,
29  *    to fit his personal naming scheme.
30  *   = it seems that a few drivers would also appreciate
31  *    nybble swapping support...
32  *   = every architecture could add their byteswap macro in asm/byteorder.h
33  *    see how some architectures already do (i386, alpha, ppc, etc)
34  *   = cpu_to_beXX and beXX_to_cpu might some day need to be well
35  *    distinguished throughout the kernel. This is not the case currently,
36  *    since little endian, big endian, and pdp endian machines needn't it.
37  *    But this might be the case for, say, a port of Linux to 20/21 bit
38  *    architectures (and F21 Linux addict around?).
39  */
40 
41 /*
42  * The following macros are to be defined by <asm/byteorder.h>:
43  *
44  * Conversion of long and short int between network and host format
45  *	ntohl(__u32 x)
46  *	ntohs(__u16 x)
47  *	htonl(__u32 x)
48  *	htons(__u16 x)
49  * It seems that some programs (which? where? or perhaps a standard? POSIX?)
50  * might like the above to be functions, not macros (why?).
51  * if that's true, then detect them, and take measures.
52  * Anyway, the measure is: define only ___ntohl as a macro instead,
53  * and in a separate file, have
54  * unsigned long inline ntohl(x){return ___ntohl(x);}
55  *
56  * The same for constant arguments
57  *	__constant_ntohl(__u32 x)
58  *	__constant_ntohs(__u16 x)
59  *	__constant_htonl(__u32 x)
60  *	__constant_htons(__u16 x)
61  *
62  * Conversion of XX-bit integers (16- 32- or 64-)
63  * between native CPU format and little/big endian format
64  * 64-bit stuff only defined for proper architectures
65  *	cpu_to_[bl]eXX(__uXX x)
66  *	[bl]eXX_to_cpu(__uXX x)
67  *
68  * The same, but takes a pointer to the value to convert
69  *	cpu_to_[bl]eXXp(__uXX x)
70  *	[bl]eXX_to_cpup(__uXX x)
71  *
72  * The same, but change in situ
73  *	cpu_to_[bl]eXXs(__uXX x)
74  *	[bl]eXX_to_cpus(__uXX x)
75  *
76  * See asm-foo/byteorder.h for examples of how to provide
77  * architecture-optimized versions
78  *
79  */
80 
81 
82 #if defined(__KERNEL__)
83 /*
84  * inside the kernel, we can use nicknames;
85  * outside of it, we must avoid POSIX namespace pollution...
86  */
87 #define cpu_to_le64 __cpu_to_le64
88 #define le64_to_cpu __le64_to_cpu
89 #define cpu_to_le32 __cpu_to_le32
90 #define le32_to_cpu __le32_to_cpu
91 #define cpu_to_le16 __cpu_to_le16
92 #define le16_to_cpu __le16_to_cpu
93 #define cpu_to_be64 __cpu_to_be64
94 #define be64_to_cpu __be64_to_cpu
95 #define cpu_to_be32 __cpu_to_be32
96 #define be32_to_cpu __be32_to_cpu
97 #define cpu_to_be16 __cpu_to_be16
98 #define be16_to_cpu __be16_to_cpu
99 #define cpu_to_le64p __cpu_to_le64p
100 #define le64_to_cpup __le64_to_cpup
101 #define cpu_to_le32p __cpu_to_le32p
102 #define le32_to_cpup __le32_to_cpup
103 #define cpu_to_le16p __cpu_to_le16p
104 #define le16_to_cpup __le16_to_cpup
105 #define cpu_to_be64p __cpu_to_be64p
106 #define be64_to_cpup __be64_to_cpup
107 #define cpu_to_be32p __cpu_to_be32p
108 #define be32_to_cpup __be32_to_cpup
109 #define cpu_to_be16p __cpu_to_be16p
110 #define be16_to_cpup __be16_to_cpup
111 #define cpu_to_le64s __cpu_to_le64s
112 #define le64_to_cpus __le64_to_cpus
113 #define cpu_to_le32s __cpu_to_le32s
114 #define le32_to_cpus __le32_to_cpus
115 #define cpu_to_le16s __cpu_to_le16s
116 #define le16_to_cpus __le16_to_cpus
117 #define cpu_to_be64s __cpu_to_be64s
118 #define be64_to_cpus __be64_to_cpus
119 #define cpu_to_be32s __cpu_to_be32s
120 #define be32_to_cpus __be32_to_cpus
121 #define cpu_to_be16s __cpu_to_be16s
122 #define be16_to_cpus __be16_to_cpus
123 #endif
124 
125 
126 /*
127  * Handle ntohl and suches. These have various compatibility
128  * issues - like we want to give the prototype even though we
129  * also have a macro for them in case some strange program
130  * wants to take the address of the thing or something..
131  *
132  * Note that these used to return a "long" in libc5, even though
133  * long is often 64-bit these days.. Thus the casts.
134  *
135  * They have to be macros in order to do the constant folding
136  * correctly - if the argument passed into a inline function
137  * it is no longer constant according to gcc..
138  */
139 
140 #undef ntohl
141 #undef ntohs
142 #undef htonl
143 #undef htons
144 
145 /*
146  * Do the prototypes. Somebody might want to take the
147  * address or some such sick thing..
148  */
149 #if defined(__KERNEL__) || (defined (__GLIBC__) && __GLIBC__ >= 2)
150 extern __u32			ntohl(__u32);
151 extern __u32			htonl(__u32);
152 #else
153 extern unsigned long int	ntohl(unsigned long int);
154 extern unsigned long int	htonl(unsigned long int);
155 #endif
156 extern unsigned short int	ntohs(unsigned short int);
157 extern unsigned short int	htons(unsigned short int);
158 
159 
160 #if defined(__GNUC__) && (__GNUC__ >= 2)
161 
162 #define ___htonl(x) __cpu_to_be32(x)
163 #define ___htons(x) __cpu_to_be16(x)
164 #define ___ntohl(x) __be32_to_cpu(x)
165 #define ___ntohs(x) __be16_to_cpu(x)
166 
167 #if defined(__KERNEL__) || (defined (__GLIBC__) && __GLIBC__ >= 2)
168 #define htonl(x) ___htonl(x)
169 #define ntohl(x) ___ntohl(x)
170 #else
171 #define htonl(x) ((unsigned long)___htonl(x))
172 #define ntohl(x) ((unsigned long)___ntohl(x))
173 #endif
174 #define htons(x) ___htons(x)
175 #define ntohs(x) ___ntohs(x)
176 
177 #endif /* OPTIMIZE */
178 
179 
180 #endif /* _LINUX_BYTEORDER_GENERIC_H */
181