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generic.h
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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  * The "... p" macros, like le64_to_cpup, can be used with pointers
9  * to unaligned data, but there will be a performance penalty on
10  * some architectures. Use get_unaligned for unaligned data.
11  *
12  * Francois-Rene Rideau <[email protected]> 19970707
13  * gathered all the good ideas from all asm-foo/byteorder.h into one file,
14  * cleaned them up.
15  * I hope it is compliant with non-GCC compilers.
16  * I decided to put __BYTEORDER_HAS_U64__ in byteorder.h,
17  * because I wasn't sure it would be ok to put it in types.h
18  * Upgraded it to 2.1.43
19  * Francois-Rene Rideau <[email protected]> 19971012
20  * Upgraded it to 2.1.57
21  * to please Linus T., replaced huge #ifdef's between little/big endian
22  * by nestedly #include'd files.
23  * Francois-Rene Rideau <[email protected]> 19971205
24  * Made it to 2.1.71; now a facelift:
25  * Put files under include/linux/byteorder/
26  * Split swab from generic support.
27  *
28  * TODO:
29  * = Regular kernel maintainers could also replace all these manual
30  * byteswap macros that remain, disseminated among drivers,
31  * after some grep or the sources...
32  * = Linus might want to rename all these macros and files to fit his taste,
33  * to fit his personal naming scheme.
34  * = it seems that a few drivers would also appreciate
35  * nybble swapping support...
36  * = every architecture could add their byteswap macro in asm/byteorder.h
37  * see how some architectures already do (i386, alpha, ppc, etc)
38  * = cpu_to_beXX and beXX_to_cpu might some day need to be well
39  * distinguished throughout the kernel. This is not the case currently,
40  * since little endian, big endian, and pdp endian machines needn't it.
41  * But this might be the case for, say, a port of Linux to 20/21 bit
42  * architectures (and F21 Linux addict around?).
43  */
44 
45 /*
46  * The following macros are to be defined by <asm/byteorder.h>:
47  *
48  * Conversion of long and short int between network and host format
49  * ntohl(__u32 x)
50  * ntohs(__u16 x)
51  * htonl(__u32 x)
52  * htons(__u16 x)
53  * It seems that some programs (which? where? or perhaps a standard? POSIX?)
54  * might like the above to be functions, not macros (why?).
55  * if that's true, then detect them, and take measures.
56  * Anyway, the measure is: define only ___ntohl as a macro instead,
57  * and in a separate file, have
58  * unsigned long inline ntohl(x){return ___ntohl(x);}
59  *
60  * The same for constant arguments
61  * __constant_ntohl(__u32 x)
62  * __constant_ntohs(__u16 x)
63  * __constant_htonl(__u32 x)
64  * __constant_htons(__u16 x)
65  *
66  * Conversion of XX-bit integers (16- 32- or 64-)
67  * between native CPU format and little/big endian format
68  * 64-bit stuff only defined for proper architectures
69  * cpu_to_[bl]eXX(__uXX x)
70  * [bl]eXX_to_cpu(__uXX x)
71  *
72  * The same, but takes a pointer to the value to convert
73  * cpu_to_[bl]eXXp(__uXX x)
74  * [bl]eXX_to_cpup(__uXX x)
75  *
76  * The same, but change in situ
77  * cpu_to_[bl]eXXs(__uXX x)
78  * [bl]eXX_to_cpus(__uXX x)
79  *
80  * See asm-foo/byteorder.h for examples of how to provide
81  * architecture-optimized versions
82  *
83  */
84 
85 #define cpu_to_le64 __cpu_to_le64
86 #define le64_to_cpu __le64_to_cpu
87 #define cpu_to_le32 __cpu_to_le32
88 #define le32_to_cpu __le32_to_cpu
89 #define cpu_to_le16 __cpu_to_le16
90 #define le16_to_cpu __le16_to_cpu
91 #define cpu_to_be64 __cpu_to_be64
92 #define be64_to_cpu __be64_to_cpu
93 #define cpu_to_be32 __cpu_to_be32
94 #define be32_to_cpu __be32_to_cpu
95 #define cpu_to_be16 __cpu_to_be16
96 #define be16_to_cpu __be16_to_cpu
97 #define cpu_to_le64p __cpu_to_le64p
98 #define le64_to_cpup __le64_to_cpup
99 #define cpu_to_le32p __cpu_to_le32p
100 #define le32_to_cpup __le32_to_cpup
101 #define cpu_to_le16p __cpu_to_le16p
102 #define le16_to_cpup __le16_to_cpup
103 #define cpu_to_be64p __cpu_to_be64p
104 #define be64_to_cpup __be64_to_cpup
105 #define cpu_to_be32p __cpu_to_be32p
106 #define be32_to_cpup __be32_to_cpup
107 #define cpu_to_be16p __cpu_to_be16p
108 #define be16_to_cpup __be16_to_cpup
109 #define cpu_to_le64s __cpu_to_le64s
110 #define le64_to_cpus __le64_to_cpus
111 #define cpu_to_le32s __cpu_to_le32s
112 #define le32_to_cpus __le32_to_cpus
113 #define cpu_to_le16s __cpu_to_le16s
114 #define le16_to_cpus __le16_to_cpus
115 #define cpu_to_be64s __cpu_to_be64s
116 #define be64_to_cpus __be64_to_cpus
117 #define cpu_to_be32s __cpu_to_be32s
118 #define be32_to_cpus __be32_to_cpus
119 #define cpu_to_be16s __cpu_to_be16s
120 #define be16_to_cpus __be16_to_cpus
121 
122 /*
123  * They have to be macros in order to do the constant folding
124  * correctly - if the argument passed into a inline function
125  * it is no longer constant according to gcc..
126  */
127 
128 #undef ntohl
129 #undef ntohs
130 #undef htonl
131 #undef htons
132 
133 #define ___htonl(x) __cpu_to_be32(x)
134 #define ___htons(x) __cpu_to_be16(x)
135 #define ___ntohl(x) __be32_to_cpu(x)
136 #define ___ntohs(x) __be16_to_cpu(x)
137 
138 #define htonl(x) ___htonl(x)
139 #define ntohl(x) ___ntohl(x)
140 #define htons(x) ___htons(x)
141 #define ntohs(x) ___ntohs(x)
142 
143 static inline void le16_add_cpu(__le16 *var, u16 val)
144 {
145  *var = cpu_to_le16(le16_to_cpu(*var) + val);
146 }
147 
148 static inline void le32_add_cpu(__le32 *var, u32 val)
149 {
150  *var = cpu_to_le32(le32_to_cpu(*var) + val);
151 }
152 
153 static inline void le64_add_cpu(__le64 *var, u64 val)
154 {
155  *var = cpu_to_le64(le64_to_cpu(*var) + val);
156 }
157 
158 static inline void be16_add_cpu(__be16 *var, u16 val)
159 {
160  *var = cpu_to_be16(be16_to_cpu(*var) + val);
161 }
162 
163 static inline void be32_add_cpu(__be32 *var, u32 val)
164 {
165  *var = cpu_to_be32(be32_to_cpu(*var) + val);
166 }
167 
168 static inline void be64_add_cpu(__be64 *var, u64 val)
169 {
170  *var = cpu_to_be64(be64_to_cpu(*var) + val);
171 }
172 
173 #endif /* _LINUX_BYTEORDER_GENERIC_H */