xref: /netbsd/sys/sys/bswap.h (revision 6550d01e)
1 /*      $NetBSD: bswap.h,v 1.16 2009/08/08 21:23:15 christos Exp $      */
2 
3 /* Written by Manuel Bouyer. Public domain */
4 
5 #ifndef _SYS_BSWAP_H_
6 #define _SYS_BSWAP_H_
7 
8 #ifndef _LOCORE
9 #include <sys/cdefs.h>
10 #include <sys/types.h>
11 
12 #include <machine/bswap.h>
13 
14 __BEGIN_DECLS
15 /* Always declare the functions in case their address is taken (etc) */
16 #if defined(_KERNEL) || defined(_STANDALONE) || !defined(__BSWAP_RENAME)
17 uint16_t bswap16(uint16_t) __constfunc;
18 uint32_t bswap32(uint32_t) __constfunc;
19 #else
20 uint16_t bswap16(uint16_t) __RENAME(__bswap16) __constfunc;
21 uint32_t bswap32(uint32_t) __RENAME(__bswap32) __constfunc;
22 #endif
23 uint64_t bswap64(uint64_t) __constfunc;
24 __END_DECLS
25 
26 #if defined(__GNUC__) && defined(__OPTIMIZE__) && !defined(__lint__)
27 
28 /* machine/byte_swap.h might have defined inline versions */
29 #ifndef __BYTE_SWAP_U64_VARIABLE
30 #define	__BYTE_SWAP_U64_VARIABLE bswap64
31 #endif
32 
33 #ifndef __BYTE_SWAP_U32_VARIABLE
34 #define	__BYTE_SWAP_U32_VARIABLE bswap32
35 #endif
36 
37 #ifndef __BYTE_SWAP_U16_VARIABLE
38 #define	__BYTE_SWAP_U16_VARIABLE bswap16
39 #endif
40 
41 #define	__byte_swap_u64_constant(x) \
42 	(__CAST(uint64_t, \
43 	 ((((x) & 0xff00000000000000ull) >> 56) | \
44 	  (((x) & 0x00ff000000000000ull) >> 40) | \
45 	  (((x) & 0x0000ff0000000000ull) >> 24) | \
46 	  (((x) & 0x000000ff00000000ull) >>  8) | \
47 	  (((x) & 0x00000000ff000000ull) <<  8) | \
48 	  (((x) & 0x0000000000ff0000ull) << 24) | \
49 	  (((x) & 0x000000000000ff00ull) << 40) | \
50 	  (((x) & 0x00000000000000ffull) << 56))))
51 
52 #define	__byte_swap_u32_constant(x) \
53 	(__CAST(uint32_t, \
54 	((((x) & 0xff000000) >> 24) | \
55 	 (((x) & 0x00ff0000) >>  8) | \
56 	 (((x) & 0x0000ff00) <<  8) | \
57 	 (((x) & 0x000000ff) << 24))))
58 
59 #define	__byte_swap_u16_constant(x) \
60 	(__CAST(uint16_t, \
61 	((((x) & 0xff00) >> 8) | \
62 	 (((x) & 0x00ff) << 8))))
63 
64 #define	bswap64(x) \
65 	(__builtin_constant_p((x)) ? \
66 	 __byte_swap_u64_constant(x) : __BYTE_SWAP_U64_VARIABLE(x))
67 
68 #define	bswap32(x) \
69 	(__builtin_constant_p((x)) ? \
70 	 __byte_swap_u32_constant(x) : __BYTE_SWAP_U32_VARIABLE(x))
71 
72 #define	bswap16(x) \
73 	(__builtin_constant_p((x)) ? \
74 	 __byte_swap_u16_constant(x) : __BYTE_SWAP_U16_VARIABLE(x))
75 
76 #endif /* __GNUC__ && __OPTIMIZE__ */
77 #endif /* !_LOCORE */
78 
79 #endif /* !_SYS_BSWAP_H_ */
80